Add flag to ThemeData to expand tap targets of certain material widgets (#18369)

packages/flutter/lib/src/material/button.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter/foundation.dart';
+import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 
 import 'button_theme.dart';
@@ -11,6 +12,7 @@ import 'constants.dart';
 import 'ink_well.dart';
 import 'material.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 
 /// Creates a button based on [Semantics], [Material], and [InkWell]
 /// widgets.
@@ -38,13 +40,14 @@ class RawMaterialButton extends StatefulWidget {
     this.elevation = 2.0,
     this.highlightElevation = 8.0,
     this.disabledElevation = 0.0,
-    this.outerPadding,
     this.padding = EdgeInsets.zero,
     this.constraints = const BoxConstraints(minWidth: 88.0, minHeight: 36.0),
     this.shape = const RoundedRectangleBorder(),
     this.animationDuration = kThemeChangeDuration,
+    MaterialTapTargetSize materialTapTargetSize,
     this.child,
-  }) : assert(shape != null),
+  }) : this.materialTapTargetSize = materialTapTargetSize ?? MaterialTapTargetSize.padded,
+       assert(shape != null),
        assert(elevation != null),
        assert(highlightElevation != null),
        assert(disabledElevation != null),
@@ -58,10 +61,6 @@ class RawMaterialButton extends StatefulWidget {
   /// If this is set to null, the button will be disabled, see [enabled].
   final VoidCallback onPressed;
 
-  /// Padding to increase the size of the gesture detector which doesn't
-  /// increase the visible material of the button.
-  final EdgeInsets outerPadding;
-
   /// Called by the underlying [InkWell] widget's [InkWell.onHighlightChanged]
   /// callback.
   final ValueChanged<bool> onHighlightChanged;
@@ -138,6 +137,15 @@ class RawMaterialButton extends StatefulWidget {
   /// property to a non-null value.
   bool get enabled => onPressed != null;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [MaterialTapTargetSize.padded].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   @override
   _RawMaterialButtonState createState() => new _RawMaterialButtonState();
 }
@@ -186,18 +194,23 @@ class _RawMaterialButtonState extends State<RawMaterialButton> {
         ),
       ),
     );
-
-    if (widget.outerPadding != null) {
-      result = new GestureDetector(
-        behavior: HitTestBehavior.translucent,
-        excludeFromSemantics: true,
-        onTap: widget.onPressed,
-        child: new Padding(
-          padding: widget.outerPadding,
-          child: result
-        ),
-      );
+    BoxConstraints constraints;
+    switch (widget.materialTapTargetSize) {
+      case MaterialTapTargetSize.padded:
+        constraints = const BoxConstraints(minWidth: 48.0, minHeight: 48.0);
+        break;
+      case MaterialTapTargetSize.shrinkWrap:
+        constraints = const BoxConstraints();
+        break;
     }
+    result = new _ButtonRedirectingHitDetectionWidget(
+      constraints: constraints,
+      child: new Center(
+        child: result,
+        widthFactor: 1.0,
+        heightFactor: 1.0,
+      ),
+    );
 
     return new Semantics(
       container: true,
@@ -248,6 +261,7 @@ class MaterialButton extends StatelessWidget {
     this.minWidth,
     this.height,
     this.padding,
+    this.materialTapTargetSize,
     @required this.onPressed,
     this.child
   }) : super(key: key);
@@ -353,6 +367,15 @@ class MaterialButton extends StatelessWidget {
   /// {@macro flutter.widgets.child}
   final Widget child;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   /// Whether the button is enabled or disabled. Buttons are disabled by default. To
   /// enable a button, set its [onPressed] property to a non-null value.
   bool get enabled => onPressed != null;
@@ -412,6 +435,7 @@ class MaterialButton extends StatelessWidget {
       ),
       shape: buttonTheme.shape,
       child: child,
+      materialTapTargetSize: materialTapTargetSize ?? theme.materialTapTargetSize,
     );
   }
 
@@ -421,3 +445,38 @@ class MaterialButton extends StatelessWidget {
     properties.add(new FlagProperty('enabled', value: enabled, ifFalse: 'disabled'));
   }
 }
+
+/// Redirects the position passed to [RenderBox.hitTest] to the center of the widget.
+///
+/// The primary purpose of this widget is to allow padding around [Material] widgets
+/// to trigger the child ink feature without increasing the size of the material.
+class _ButtonRedirectingHitDetectionWidget extends SingleChildRenderObjectWidget {
+  const _ButtonRedirectingHitDetectionWidget({
+    Key key,
+    Widget child,
+    this.constraints
+  }) : super(key: key, child: child);
+
+  final BoxConstraints constraints;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return new _RenderButtonRedirectingHitDetection(constraints);
+  }
+
+  @override
+  void updateRenderObject(BuildContext context, covariant _RenderButtonRedirectingHitDetection renderObject) {
+    renderObject.additionalConstraints = constraints;
+  }
+}
+
+class _RenderButtonRedirectingHitDetection extends RenderConstrainedBox {
+  _RenderButtonRedirectingHitDetection (BoxConstraints additionalConstraints) : super(additionalConstraints: additionalConstraints);
+
+  @override
+  bool hitTest(HitTestResult result, {Offset position}) {
+    if (!size.contains(position))
+      return false;
+    return child.hitTest(result, position: size.center(Offset.zero));
+  }
+}

packages/flutter/lib/src/material/checkbox.dart

@@ -10,6 +10,7 @@ import 'package:flutter/widgets.dart';
 import 'constants.dart';
 import 'debug.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 import 'toggleable.dart';
 
 /// A material design checkbox.
@@ -58,6 +59,7 @@ class Checkbox extends StatefulWidget {
     this.tristate = false,
     @required this.onChanged,
     this.activeColor,
+    this.materialTapTargetSize,
   }) : assert(tristate != null),
        assert(tristate || value != null),
        super(key: key);
@@ -113,6 +115,15 @@ class Checkbox extends StatefulWidget {
   /// If tristate is false (the default), [value] must not be null.
   final bool tristate;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   /// The width of a checkbox widget.
   static const double width = 18.0;
 
@@ -125,12 +136,23 @@ class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin {
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterial(context));
     final ThemeData themeData = Theme.of(context);
+    Size size;
+    switch (widget.materialTapTargetSize ?? themeData.materialTapTargetSize) {
+      case MaterialTapTargetSize.padded:
+        size = const Size(2 * kRadialReactionRadius + 8.0, 2 * kRadialReactionRadius + 8.0);
+        break;
+      case MaterialTapTargetSize.shrinkWrap:
+        size = const Size(2 * kRadialReactionRadius, 2 * kRadialReactionRadius);
+        break;
+    }
+    final BoxConstraints additionalConstraints = new BoxConstraints.tight(size);
     return new _CheckboxRenderObjectWidget(
       value: widget.value,
       tristate: widget.tristate,
       activeColor: widget.activeColor ?? themeData.toggleableActiveColor,
       inactiveColor: widget.onChanged != null ? themeData.unselectedWidgetColor : themeData.disabledColor,
       onChanged: widget.onChanged,
+      additionalConstraints: additionalConstraints,
       vsync: this,
     );
   }
@@ -145,6 +167,7 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
     @required this.inactiveColor,
     @required this.onChanged,
     @required this.vsync,
+    @required this.additionalConstraints,
   }) : assert(tristate != null),
        assert(tristate || value != null),
        assert(activeColor != null),
@@ -158,6 +181,7 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
   final Color inactiveColor;
   final ValueChanged<bool> onChanged;
   final TickerProvider vsync;
+  final BoxConstraints additionalConstraints;
 
   @override
   _RenderCheckbox createRenderObject(BuildContext context) => new _RenderCheckbox(
@@ -167,6 +191,7 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
     inactiveColor: inactiveColor,
     onChanged: onChanged,
     vsync: vsync,
+    additionalConstraints: additionalConstraints,
   );
 
   @override
@@ -177,6 +202,7 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
       ..activeColor = activeColor
       ..inactiveColor = inactiveColor
       ..onChanged = onChanged
+      ..additionalConstraints = additionalConstraints
       ..vsync = vsync;
   }
 }
@@ -191,6 +217,7 @@ class _RenderCheckbox extends RenderToggleable {
     bool tristate,
     Color activeColor,
     Color inactiveColor,
+    BoxConstraints additionalConstraints,
     ValueChanged<bool> onChanged,
     @required TickerProvider vsync,
   }): _oldValue = value,
@@ -200,7 +227,7 @@ class _RenderCheckbox extends RenderToggleable {
         activeColor: activeColor,
         inactiveColor: inactiveColor,
         onChanged: onChanged,
-        size: const Size(2 * kRadialReactionRadius, 2 * kRadialReactionRadius),
+        additionalConstraints: additionalConstraints,
         vsync: vsync,
       );
 

packages/flutter/lib/src/material/checkbox_list_tile.dart

@@ -7,6 +7,7 @@ import 'package:flutter/widgets.dart';
 import 'checkbox.dart';
 import 'list_tile.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 
 /// A [ListTile] with a [Checkbox]. In other words, a checkbox with a label.
 ///
@@ -173,6 +174,7 @@ class CheckboxListTile extends StatelessWidget {
       value: value,
       onChanged: onChanged,
       activeColor: activeColor,
+      materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
     );
     Widget leading, trailing;
     switch (controlAffinity) {

packages/flutter/lib/src/material/chip.dart

@@ -17,6 +17,7 @@ import 'ink_well.dart';
 import 'material.dart';
 import 'material_localizations.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 import 'tooltip.dart';
 
 // Some design constants
@@ -99,6 +100,15 @@ abstract class ChipAttributes {
   /// By default, this is 4 logical pixels at the beginning and the end of the
   /// label, and zero on top and bottom.
   EdgeInsetsGeometry get labelPadding;
+
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  MaterialTapTargetSize get materialTapTargetSize;
 }
 
 /// An interface for material design chips that can be deleted.
@@ -423,6 +433,7 @@ class Chip extends StatelessWidget implements ChipAttributes, DeletableChipAttri
     this.shape,
     this.backgroundColor,
     this.padding,
+    this.materialTapTargetSize,
   })  : assert(label != null),
         super(key: key);
 
@@ -448,6 +459,8 @@ class Chip extends StatelessWidget implements ChipAttributes, DeletableChipAttri
   final Color deleteIconColor;
   @override
   final String deleteButtonTooltipMessage;
+  @override
+  final MaterialTapTargetSize materialTapTargetSize;
 
   @override
   Widget build(BuildContext context) {
@@ -465,6 +478,7 @@ class Chip extends StatelessWidget implements ChipAttributes, DeletableChipAttri
       shape: shape,
       backgroundColor: backgroundColor,
       padding: padding,
+      materialTapTargetSize: materialTapTargetSize,
       isEnabled: true,
     );
   }
@@ -547,6 +561,7 @@ class InputChip extends StatelessWidget
     this.shape,
     this.backgroundColor,
     this.padding,
+    this.materialTapTargetSize,
   })  : assert(selected != null),
         assert(isEnabled != null),
         assert(label != null),
@@ -588,6 +603,8 @@ class InputChip extends StatelessWidget
   final Color backgroundColor;
   @override
   final EdgeInsetsGeometry padding;
+  @override
+  final MaterialTapTargetSize materialTapTargetSize;
 
   @override
   Widget build(BuildContext context) {
@@ -611,6 +628,7 @@ class InputChip extends StatelessWidget
       shape: shape,
       backgroundColor: backgroundColor,
       padding: padding,
+      materialTapTargetSize: materialTapTargetSize,
       isEnabled: isEnabled && (onSelected != null || onDeleted != null || onPressed != null),
     );
   }
@@ -689,6 +707,7 @@ class ChoiceChip extends StatelessWidget
     this.shape,
     this.backgroundColor,
     this.padding,
+    this.materialTapTargetSize,
   })  : assert(selected != null),
         assert(label != null),
         super(key: key);
@@ -717,6 +736,8 @@ class ChoiceChip extends StatelessWidget
   final Color backgroundColor;
   @override
   final EdgeInsetsGeometry padding;
+  @override
+  final MaterialTapTargetSize materialTapTargetSize;
 
   @override
   bool get isEnabled => onSelected != null;
@@ -741,6 +762,7 @@ class ChoiceChip extends StatelessWidget
       backgroundColor: backgroundColor,
       padding: padding,
       isEnabled: isEnabled,
+      materialTapTargetSize: materialTapTargetSize,
     );
   }
 }
@@ -852,6 +874,7 @@ class FilterChip extends StatelessWidget
     this.shape,
     this.backgroundColor,
     this.padding,
+    this.materialTapTargetSize,
   })  : assert(selected != null),
         assert(label != null),
         super(key: key);
@@ -880,6 +903,8 @@ class FilterChip extends StatelessWidget
   final Color backgroundColor;
   @override
   final EdgeInsetsGeometry padding;
+  @override
+  final MaterialTapTargetSize materialTapTargetSize;
 
   @override
   bool get isEnabled => onSelected != null;
@@ -901,6 +926,7 @@ class FilterChip extends StatelessWidget
       selectedColor: selectedColor,
       padding: padding,
       isEnabled: isEnabled,
+      materialTapTargetSize: materialTapTargetSize,
     );
   }
 }
@@ -966,6 +992,7 @@ class ActionChip extends StatelessWidget implements ChipAttributes, TappableChip
     this.shape,
     this.backgroundColor,
     this.padding,
+    this.materialTapTargetSize,
   })  : assert(label != null),
         assert(
           onPressed != null,
@@ -992,6 +1019,8 @@ class ActionChip extends StatelessWidget implements ChipAttributes, TappableChip
   final Color backgroundColor;
   @override
   final EdgeInsetsGeometry padding;
+  @override
+  final MaterialTapTargetSize materialTapTargetSize;
 
   @override
   Widget build(BuildContext context) {
@@ -1007,6 +1036,7 @@ class ActionChip extends StatelessWidget implements ChipAttributes, TappableChip
       padding: padding,
       labelPadding: labelPadding,
       isEnabled: true,
+      materialTapTargetSize: materialTapTargetSize
     );
   }
 }
@@ -1076,6 +1106,7 @@ class RawChip extends StatefulWidget
     this.tooltip,
     this.shape,
     this.backgroundColor,
+    this.materialTapTargetSize,
   })  : assert(label != null),
         assert(isEnabled != null),
         deleteIcon = deleteIcon ?? _kDefaultDeleteIcon,
@@ -1117,6 +1148,8 @@ class RawChip extends StatefulWidget
   final Color backgroundColor;
   @override
   final EdgeInsetsGeometry padding;
+  @override
+  final MaterialTapTargetSize materialTapTargetSize;
 
   /// Whether or not to show a check mark when [selected] is true.
   ///
@@ -1368,7 +1401,7 @@ class _RawChipState extends State<RawChip> with TickerProviderStateMixin<RawChip
     final TextDirection textDirection = Directionality.of(context);
     final ShapeBorder shape = widget.shape ?? chipTheme.shape;
 
-    return new Material(
+    Widget result = new Material(
       elevation: isTapping ? _kPressElevation : 0.0,
       animationDuration: pressedAnimationDuration,
       shape: shape,
@@ -1428,6 +1461,68 @@ class _RawChipState extends State<RawChip> with TickerProviderStateMixin<RawChip
         ),
       ),
     );
+    BoxConstraints constraints;
+    switch (widget.materialTapTargetSize ?? theme.materialTapTargetSize) {
+      case MaterialTapTargetSize.padded:
+        constraints = const BoxConstraints(minHeight: 48.0);
+        break;
+      case MaterialTapTargetSize.shrinkWrap:
+        constraints = const BoxConstraints();
+        break;
+    }
+    result = _ChipRedirectingHitDetectionWidget(
+      constraints: constraints,
+      child: new Center(
+        child: result,
+        widthFactor: 1.0,
+        heightFactor: 1.0,
+      ),
+    );
+    return new Semantics(
+      container: true,
+      selected: widget.selected,
+      enabled: canTap ? widget.isEnabled : null,
+      child: result,
+    );
+  }
+}
+
+/// Redirects the [position.dy] passed to [RenderBox.hitTest] to the vertical
+/// center of the widget.
+///
+/// The primary purpose of this widget is to allow padding around the [RawChip]
+/// to trigger the child ink feature without increasing the size of the material.
+class _ChipRedirectingHitDetectionWidget extends SingleChildRenderObjectWidget {
+  const _ChipRedirectingHitDetectionWidget({
+    Key key,
+    Widget child,
+    this.constraints,
+  }) : super(key: key, child: child);
+
+  final BoxConstraints constraints;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return new _RenderChipRedirectingHitDetection(constraints);
+  }
+
+  @override
+  void updateRenderObject(BuildContext context, covariant _RenderChipRedirectingHitDetection renderObject) {
+    renderObject.additionalConstraints = constraints;
+  }
+}
+
+class _RenderChipRedirectingHitDetection extends RenderConstrainedBox {
+  _RenderChipRedirectingHitDetection(BoxConstraints additionalConstraints) : super(additionalConstraints: additionalConstraints);
+
+  @override
+  bool hitTest(HitTestResult result, {Offset position}) {
+    if (!size.contains(position))
+      return false;
+    // Only redirects hit detection which occurs above and below the render object.
+    // In order to make this assumption true, I have removed the minimum width
+    // constraints, since any reasonable chip would be at least that wide.
+    return child.hitTest(result, position: new Offset(position.dx, size.height / 2));
   }
 }
 
@@ -1932,6 +2027,28 @@ class _RenderChip extends RenderBox {
     return new Size(deleteIconWidth, deleteIconHeight);
   }
 
+  @override
+  bool hitTest(HitTestResult result, {Offset position}) {
+    if (!size.contains(position))
+      return false;
+    RenderBox hitTestChild;
+    switch (textDirection) {
+      case TextDirection.ltr:
+        if (position.dx / size.width > 0.66)
+          hitTestChild = deleteIcon ?? label ?? avatar;
+        else
+          hitTestChild = label ?? avatar;
+        break;
+      case TextDirection.rtl:
+        if (position.dx / size.width < 0.33)
+          hitTestChild = deleteIcon ?? label ?? avatar;
+        else
+          hitTestChild = label ?? avatar;
+        break;
+    }
+    return hitTestChild?.hitTest(result, position: hitTestChild.size.center(Offset.zero)) ?? false;
+  }
+
   @override
   void performLayout() {
     final BoxConstraints contentConstraints = constraints.loosen();
@@ -2250,20 +2367,4 @@ class _RenderChip extends RenderBox {
 
   @override
   bool hitTestSelf(Offset position) => deleteButtonRect.contains(position) || pressRect.contains(position);
-
-  @override
-  bool hitTestChildren(HitTestResult result, {@required Offset position}) {
-    assert(position != null);
-    if (deleteIcon != null && deleteButtonRect.contains(position)) {
-      // This simulates a position at the center of the delete icon if the hit
-      // on the chip is inside of the delete area.
-      return deleteIcon.hitTest(result, position: (Offset.zero & _boxSize(deleteIcon)).center);
-    }
-    for (RenderBox child in _children) {
-      if (child.hasSize && child.hitTest(result, position: position - _boxParentData(child).offset)) {
-        return true;
-      }
-    }
-    return false;
-  }
 }

packages/flutter/lib/src/material/flat_button.dart

@@ -9,6 +9,7 @@ import 'button.dart';
 import 'button_theme.dart';
 import 'colors.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 
 /// A material design "flat button".
 ///
@@ -62,6 +63,7 @@ class FlatButton extends StatelessWidget {
     this.colorBrightness,
     this.padding,
     this.shape,
+    this.materialTapTargetSize,
     @required this.child,
   }) : super(key: key);
 
@@ -85,6 +87,7 @@ class FlatButton extends StatelessWidget {
     this.splashColor,
     this.colorBrightness,
     this.shape,
+    this.materialTapTargetSize,
     @required Widget icon,
     @required Widget label,
   }) : assert(icon != null),
@@ -185,6 +188,15 @@ class FlatButton extends StatelessWidget {
   /// Defaults to the theme's brightness, [ThemeData.brightness].
   final Brightness colorBrightness;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   /// The widget below this widget in the tree.
   ///
   /// Typically a [Text] widget in all caps.
@@ -290,6 +302,7 @@ class FlatButton extends StatelessWidget {
       splashColor: _getSplashColor(theme, buttonTheme),
       elevation: 0.0,
       highlightElevation: 0.0,
+      materialTapTargetSize: materialTapTargetSize ?? theme.materialTapTargetSize,
       padding: padding ?? buttonTheme.padding,
       constraints: buttonTheme.constraints,
       shape: shape ?? buttonTheme.shape,
@@ -311,5 +324,6 @@ class FlatButton extends StatelessWidget {
     properties.add(new DiagnosticsProperty<Brightness>('colorBrightness', colorBrightness, defaultValue: null));
     properties.add(new DiagnosticsProperty<EdgeInsetsGeometry>('padding', padding, defaultValue: null));
     properties.add(new DiagnosticsProperty<ShapeBorder>('shape', shape, defaultValue: null));
+    properties.add(new DiagnosticsProperty<MaterialTapTargetSize>('materialTapTargetSize', materialTapTargetSize, defaultValue: null));
   }
 }

packages/flutter/lib/src/material/floating_action_button.dart

@@ -8,6 +8,7 @@ import 'package:flutter/widgets.dart';
 import 'button.dart';
 import 'scaffold.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 import 'tooltip.dart';
 
 const BoxConstraints _kSizeConstraints = const BoxConstraints.tightFor(
@@ -67,6 +68,7 @@ class FloatingActionButton extends StatefulWidget {
     @required this.onPressed,
     this.mini = false,
     this.shape = const CircleBorder(),
+    this.materialTapTargetSize,
     this.isExtended = false,
   }) :  assert(elevation != null),
         assert(highlightElevation != null),
@@ -92,6 +94,7 @@ class FloatingActionButton extends StatefulWidget {
     @required this.onPressed,
     this.shape = const StadiumBorder(),
     this.isExtended = true,
+    this.materialTapTargetSize,
     @required Widget icon,
     @required Widget label,
   }) :  assert(elevation != null),
@@ -196,6 +199,15 @@ class FloatingActionButton extends StatefulWidget {
   /// floating action buttons are scaled and faded in.
   final bool isExtended;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   final BoxConstraints _sizeConstraints;
 
   @override
@@ -241,7 +253,7 @@ class _FloatingActionButtonState extends State<FloatingActionButton> {
       onHighlightChanged: _handleHighlightChanged,
       elevation: _highlight ? widget.highlightElevation : widget.elevation,
       constraints: widget._sizeConstraints,
-      outerPadding: widget.mini ? const EdgeInsets.all(4.0) : null,
+      materialTapTargetSize: widget.materialTapTargetSize ?? theme.materialTapTargetSize,
       fillColor: widget.backgroundColor ?? theme.accentColor,
       textStyle: theme.accentTextTheme.button.copyWith(
         color: foregroundColor,

packages/flutter/lib/src/material/input_border.dart

@@ -31,7 +31,7 @@ abstract class InputBorder extends ShapeBorder {
   /// No input border.
   ///
   /// Use this value with [InputDecoration.border] to specify that no border
-  /// should be drawn. The [InputDecoration.collapsed] constructor sets
+  /// should be drawn. The [InputDecoration.shrinkWrap] constructor sets
   /// its border to this value.
   static const InputBorder none = const _NoInputBorder();
 

packages/flutter/lib/src/material/radio.dart

@@ -8,6 +8,7 @@ import 'package:flutter/widgets.dart';
 import 'constants.dart';
 import 'debug.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 import 'toggleable.dart';
 
 const double _kOuterRadius = 8.0;
@@ -54,7 +55,8 @@ class Radio<T> extends StatefulWidget {
     @required this.value,
     @required this.groupValue,
     @required this.onChanged,
-    this.activeColor
+    this.activeColor,
+    this.materialTapTargetSize,
   }) : super(key: key);
 
   /// The value represented by this radio button.
@@ -96,6 +98,15 @@ class Radio<T> extends StatefulWidget {
   /// Defaults to [ThemeData.toggleableActiveColor].
   final Color activeColor;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   @override
   _RadioState<T> createState() => new _RadioState<T>();
 }
@@ -116,11 +127,22 @@ class _RadioState<T> extends State<Radio<T>> with TickerProviderStateMixin {
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterial(context));
     final ThemeData themeData = Theme.of(context);
+    Size size;
+    switch (widget.materialTapTargetSize ?? themeData.materialTapTargetSize) {
+      case MaterialTapTargetSize.padded:
+        size = const Size(2 * kRadialReactionRadius + 8.0, 2 * kRadialReactionRadius + 8.0);
+        break;
+      case MaterialTapTargetSize.shrinkWrap:
+        size = const Size(2 * kRadialReactionRadius, 2 * kRadialReactionRadius);
+        break;
+    }
+    final BoxConstraints additionalConstraints = new BoxConstraints.tight(size);
     return new _RadioRenderObjectWidget(
       selected: widget.value == widget.groupValue,
       activeColor: widget.activeColor ?? themeData.toggleableActiveColor,
       inactiveColor: _getInactiveColor(themeData),
       onChanged: _enabled ? _handleChanged : null,
+      additionalConstraints: additionalConstraints,
       vsync: this,
     );
   }
@@ -132,6 +154,7 @@ class _RadioRenderObjectWidget extends LeafRenderObjectWidget {
     @required this.selected,
     @required this.activeColor,
     @required this.inactiveColor,
+    @required this.additionalConstraints,
     this.onChanged,
     @required this.vsync,
   }) : assert(selected != null),
@@ -145,6 +168,7 @@ class _RadioRenderObjectWidget extends LeafRenderObjectWidget {
   final Color activeColor;
   final ValueChanged<bool> onChanged;
   final TickerProvider vsync;
+  final BoxConstraints additionalConstraints;
 
   @override
   _RenderRadio createRenderObject(BuildContext context) => new _RenderRadio(
@@ -153,6 +177,7 @@ class _RadioRenderObjectWidget extends LeafRenderObjectWidget {
     inactiveColor: inactiveColor,
     onChanged: onChanged,
     vsync: vsync,
+    additionalConstraints: additionalConstraints,
   );
 
   @override
@@ -162,6 +187,7 @@ class _RadioRenderObjectWidget extends LeafRenderObjectWidget {
       ..activeColor = activeColor
       ..inactiveColor = inactiveColor
       ..onChanged = onChanged
+      ..additionalConstraints = additionalConstraints
       ..vsync = vsync;
   }
 }
@@ -172,6 +198,7 @@ class _RenderRadio extends RenderToggleable {
     Color activeColor,
     Color inactiveColor,
     ValueChanged<bool> onChanged,
+    BoxConstraints additionalConstraints,
     @required TickerProvider vsync,
   }): super(
     value: value,
@@ -179,7 +206,7 @@ class _RenderRadio extends RenderToggleable {
     activeColor: activeColor,
     inactiveColor: inactiveColor,
     onChanged: onChanged,
-    size: const Size(2 * kRadialReactionRadius, 2 * kRadialReactionRadius),
+    additionalConstraints: additionalConstraints,
     vsync: vsync,
   );
 

packages/flutter/lib/src/material/radio_list_tile.dart

@@ -7,6 +7,7 @@ import 'package:flutter/widgets.dart';
 import 'list_tile.dart';
 import 'radio.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 
 /// A [ListTile] with a [Radio]. In other words, a radio button with a label.
 ///
@@ -198,6 +199,7 @@ class RadioListTile<T> extends StatelessWidget {
       groupValue: groupValue,
       onChanged: onChanged,
       activeColor: activeColor,
+      materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
     );
     Widget leading, trailing;
     switch (controlAffinity) {

packages/flutter/lib/src/material/raised_button.dart

@@ -10,6 +10,7 @@ import 'button_theme.dart';
 import 'colors.dart';
 import 'constants.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 
 /// A material design "raised button".
 ///
@@ -62,6 +63,7 @@ class RaisedButton extends StatelessWidget {
     this.disabledElevation = 0.0,
     this.padding,
     this.shape,
+    this.materialTapTargetSize,
     this.animationDuration = kThemeChangeDuration,
     this.child,
   }) : assert(elevation != null),
@@ -94,6 +96,7 @@ class RaisedButton extends StatelessWidget {
     this.highlightElevation = 8.0,
     this.disabledElevation = 0.0,
     this.shape,
+    this.materialTapTargetSize,
     this.animationDuration = kThemeChangeDuration,
     @required Widget icon,
     @required Widget label,
@@ -289,6 +292,15 @@ class RaisedButton extends StatelessWidget {
   /// The default value is [kThemeChangeDuration].
   final Duration animationDuration;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   Brightness _getBrightness(ThemeData theme) {
     return colorBrightness ?? theme.brightness;
   }
@@ -380,6 +392,7 @@ class RaisedButton extends StatelessWidget {
       shape: shape ?? buttonTheme.shape,
       animationDuration: animationDuration,
       child: child,
+      materialTapTargetSize: materialTapTargetSize ?? theme.materialTapTargetSize,
     );
   }
 

packages/flutter/lib/src/material/switch.dart

@@ -12,8 +12,17 @@ import 'constants.dart';
 import 'debug.dart';
 import 'shadows.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 import 'toggleable.dart';
 
+const double _kTrackHeight = 14.0;
+const double _kTrackWidth = 33.0;
+const double _kTrackRadius = _kTrackHeight / 2.0;
+const double _kThumbRadius = 10.0;
+const double _kSwitchWidth = _kTrackWidth - 2 * _kTrackRadius + 2 * kRadialReactionRadius;
+const double _kSwitchHeight = 2 * kRadialReactionRadius + 8.0;
+const double _kSwitchHeightCollapsed = 2 * kRadialReactionRadius;
+
 /// A material design switch.
 ///
 /// Used to toggle the on/off state of a single setting.
@@ -54,7 +63,8 @@ class Switch extends StatefulWidget {
     this.inactiveThumbColor,
     this.inactiveTrackColor,
     this.activeThumbImage,
-    this.inactiveThumbImage
+    this.inactiveThumbImage,
+    this.materialTapTargetSize,
   }) : super(key: key);
 
   /// Whether this switch is on or off.
@@ -112,6 +122,15 @@ class Switch extends StatefulWidget {
   /// An image to use on the thumb of this switch when the switch is off.
   final ImageProvider inactiveThumbImage;
 
+  /// Configures the minimum size of the tap target.
+  ///
+  /// Defaults to [ThemeData.materialTapTargetSize].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialTapTargetSize], for a description of how this affects tap targets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   @override
   _SwitchState createState() => new _SwitchState();
 
@@ -142,6 +161,16 @@ class _SwitchState extends State<Switch> with TickerProviderStateMixin {
       inactiveThumbColor = widget.inactiveThumbColor ?? (isDark ? Colors.grey.shade800 : Colors.grey.shade400);
       inactiveTrackColor = widget.inactiveTrackColor ?? (isDark ? Colors.white10 : Colors.black12);
     }
+    Size size;
+    switch (widget.materialTapTargetSize ?? themeData.materialTapTargetSize) {
+      case MaterialTapTargetSize.padded:
+        size = const Size(_kSwitchWidth, _kSwitchHeight);
+        break;
+      case MaterialTapTargetSize.shrinkWrap:
+        size = const Size(_kSwitchWidth, _kSwitchHeightCollapsed);
+        break;
+    }
+    final BoxConstraints additionalConstraints = new BoxConstraints.tight(size);
 
     return new _SwitchRenderObjectWidget(
       value: widget.value,
@@ -153,6 +182,7 @@ class _SwitchState extends State<Switch> with TickerProviderStateMixin {
       inactiveTrackColor: inactiveTrackColor,
       configuration: createLocalImageConfiguration(context),
       onChanged: widget.onChanged,
+      additionalConstraints: additionalConstraints,
       vsync: this,
     );
   }
@@ -171,6 +201,7 @@ class _SwitchRenderObjectWidget extends LeafRenderObjectWidget {
     this.configuration,
     this.onChanged,
     this.vsync,
+    this.additionalConstraints,
   }) : super(key: key);
 
   final bool value;
@@ -183,6 +214,7 @@ class _SwitchRenderObjectWidget extends LeafRenderObjectWidget {
   final ImageConfiguration configuration;
   final ValueChanged<bool> onChanged;
   final TickerProvider vsync;
+  final BoxConstraints additionalConstraints;
 
   @override
   _RenderSwitch createRenderObject(BuildContext context) {
@@ -197,6 +229,7 @@ class _SwitchRenderObjectWidget extends LeafRenderObjectWidget {
       configuration: configuration,
       onChanged: onChanged,
       textDirection: Directionality.of(context),
+      additionalConstraints: additionalConstraints,
       vsync: vsync,
     );
   }
@@ -214,17 +247,11 @@ class _SwitchRenderObjectWidget extends LeafRenderObjectWidget {
       ..configuration = configuration
       ..onChanged = onChanged
       ..textDirection = Directionality.of(context)
+      ..additionalConstraints = additionalConstraints
       ..vsync = vsync;
   }
 }
 
-const double _kTrackHeight = 14.0;
-const double _kTrackWidth = 33.0;
-const double _kTrackRadius = _kTrackHeight / 2.0;
-const double _kThumbRadius = 10.0;
-const double _kSwitchWidth = _kTrackWidth - 2 * _kTrackRadius + 2 * kRadialReactionRadius;
-const double _kSwitchHeight = 2 * kRadialReactionRadius;
-
 class _RenderSwitch extends RenderToggleable {
   _RenderSwitch({
     bool value,
@@ -235,6 +262,7 @@ class _RenderSwitch extends RenderToggleable {
     Color activeTrackColor,
     Color inactiveTrackColor,
     ImageConfiguration configuration,
+    BoxConstraints additionalConstraints,
     @required TextDirection textDirection,
     ValueChanged<bool> onChanged,
     @required TickerProvider vsync,
@@ -251,7 +279,7 @@ class _RenderSwitch extends RenderToggleable {
          activeColor: activeColor,
          inactiveColor: inactiveColor,
          onChanged: onChanged,
-         size: const Size(_kSwitchWidth, _kSwitchHeight),
+         additionalConstraints: additionalConstraints,
          vsync: vsync,
        ) {
     _drag = new HorizontalDragGestureRecognizer()

packages/flutter/lib/src/material/switch_list_tile.dart

@@ -7,6 +7,7 @@ import 'package:flutter/widgets.dart';
 import 'list_tile.dart';
 import 'switch.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 
 /// A [ListTile] with a [Switch]. In other words, a switch with a label.
 ///
@@ -171,6 +172,7 @@ class SwitchListTile extends StatelessWidget {
       activeColor: activeColor,
       activeThumbImage: activeThumbImage,
       inactiveThumbImage: inactiveThumbImage,
+      materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
     );
     return new MergeSemantics(
       child: ListTileTheme.merge(

packages/flutter/lib/src/material/theme_data.dart

@@ -36,6 +36,42 @@ const Color _kLightThemeSplashColor = const Color(0x66C8C8C8);
 const Color _kDarkThemeHighlightColor = const Color(0x40CCCCCC);
 const Color _kDarkThemeSplashColor = const Color(0x40CCCCCC);
 
+/// Configures the tap target and layout size of certain Material widgets.
+///
+/// Changing the value in [ThemeData.materialTapTargetSize] will affect the
+/// accessibility experience.
+///
+/// Some of the impacted widgets include:
+///
+///   * [FloatingActionButton], only the mini tap target size is increased.
+///   * [MaterialButton]
+///   * [OutlineButton]
+///   * [FlatButton]
+///   * [RaisedButton]
+///   * [TimePicker]
+///   * [SnackBar]
+///   * [Chip]
+///   * [RawChip]
+///   * [InputChip]
+///   * [ChoiceChip]
+///   * [FilterChip]
+///   * [ActionChip]
+///   * [Radio]
+///   * [Switch]
+///   * [Checkbox]
+enum MaterialTapTargetSize {
+  /// Expands the minimum tap target size to 48px by 48px.
+  ///
+  /// This is the default value of [ThemeData.materialHitTestSize] and the
+  /// recommended size to conform to Android accessibility scanner
+  /// recommendations.
+  padded,
+
+  /// Shrinks the tap target size to the minimum provided by the Material
+  /// specification.
+  shrinkWrap,
+}
+
 /// Holds the color and typography values for a material design theme.
 ///
 /// Use this class to configure a [Theme] widget.
@@ -105,7 +141,9 @@ class ThemeData extends Diagnosticable {
     SliderThemeData sliderTheme,
     ChipThemeData chipTheme,
     TargetPlatform platform,
+    MaterialTapTargetSize materialTapTargetSize,
   }) {
+    materialTapTargetSize ??= MaterialTapTargetSize.padded;
     brightness ??= Brightness.light;
     final bool isDark = brightness == Brightness.dark;
     primarySwatch ??= Colors.blue;
@@ -208,6 +246,7 @@ class ThemeData extends Diagnosticable {
       sliderTheme: sliderTheme,
       chipTheme: chipTheme,
       platform: platform,
+      materialTapTargetSize: materialTapTargetSize,
     );
   }
 
@@ -257,6 +296,7 @@ class ThemeData extends Diagnosticable {
     @required this.sliderTheme,
     @required this.chipTheme,
     @required this.platform,
+    @required this.materialTapTargetSize,
   }) : assert(brightness != null),
        assert(primaryColor != null),
        assert(primaryColorBrightness != null),
@@ -294,7 +334,8 @@ class ThemeData extends Diagnosticable {
        assert(accentIconTheme != null),
        assert(sliderTheme != null),
        assert(chipTheme != null),
-       assert(platform != null);
+       assert(platform != null),
+       assert(materialTapTargetSize != null);
 
   /// A default light blue theme.
   ///
@@ -483,6 +524,9 @@ class ThemeData extends Diagnosticable {
   /// Defaults to the current platform.
   final TargetPlatform platform;
 
+  /// Configures the hit test size of certain Material widgets.
+  final MaterialTapTargetSize materialTapTargetSize;
+
   /// Creates a copy of this theme but with the given fields replaced with the new values.
   ThemeData copyWith({
     Brightness brightness,
@@ -524,6 +568,7 @@ class ThemeData extends Diagnosticable {
     SliderThemeData sliderTheme,
     ChipThemeData chipTheme,
     TargetPlatform platform,
+    MaterialTapTargetSize materialTapTargetSize,
   }) {
     return new ThemeData.raw(
       brightness: brightness ?? this.brightness,
@@ -565,6 +610,7 @@ class ThemeData extends Diagnosticable {
       sliderTheme: sliderTheme ?? this.sliderTheme,
       chipTheme: chipTheme ?? this.chipTheme,
       platform: platform ?? this.platform,
+      materialTapTargetSize: materialTapTargetSize ?? this.materialTapTargetSize,
     );
   }
 
@@ -692,6 +738,7 @@ class ThemeData extends Diagnosticable {
       sliderTheme: SliderThemeData.lerp(a.sliderTheme, b.sliderTheme, t),
       chipTheme: ChipThemeData.lerp(a.chipTheme, b.chipTheme, t),
       platform: t < 0.5 ? a.platform : b.platform,
+      materialTapTargetSize: t < 0.5 ? a.materialTapTargetSize : b.materialTapTargetSize,
     );
   }
 
@@ -736,7 +783,8 @@ class ThemeData extends Diagnosticable {
            (otherData.accentIconTheme == accentIconTheme) &&
            (otherData.sliderTheme == sliderTheme) &&
            (otherData.chipTheme == chipTheme) &&
-           (otherData.platform == platform);
+           (otherData.platform == platform) &&
+           (otherData.materialTapTargetSize == materialTapTargetSize);
   }
 
   @override
@@ -780,6 +828,7 @@ class ThemeData extends Diagnosticable {
         sliderTheme,
         chipTheme,
         platform,
+        materialTapTargetSize
       ),
     );
   }
@@ -824,6 +873,7 @@ class ThemeData extends Diagnosticable {
     properties.add(new DiagnosticsProperty<IconThemeData>('accentIconTheme', accentIconTheme));
     properties.add(new DiagnosticsProperty<SliderThemeData>('sliderTheme', sliderTheme));
     properties.add(new DiagnosticsProperty<ChipThemeData>('chipTheme', chipTheme));
+    properties.add(new DiagnosticsProperty<MaterialTapTargetSize>('materialTapTargetSize', materialTapTargetSize));
   }
 }
 

packages/flutter/lib/src/material/time_picker.dart

@@ -17,6 +17,7 @@ import 'feedback.dart';
 import 'flat_button.dart';
 import 'material_localizations.dart';
 import 'theme.dart';
+import 'theme_data.dart';
 import 'time.dart';
 import 'typography.dart';
 
@@ -29,11 +30,15 @@ enum _TimePickerMode { hour, minute }
 const double _kTimePickerHeaderPortraitHeight = 96.0;
 const double _kTimePickerHeaderLandscapeWidth = 168.0;
 
+
 const double _kTimePickerWidthPortrait = 328.0;
 const double _kTimePickerWidthLandscape = 512.0;
 
-const double _kTimePickerHeightPortrait = 484.0;
-const double _kTimePickerHeightLandscape = 304.0;
+const double _kTimePickerHeightPortrait = 496.0;
+const double _kTimePickerHeightLandscape = 316.0;
+
+const double _kTimePickerHeightPortraitCollapsed = 484.0;
+const double _kTimePickerHeightLandscapeCollapsed = 304.0;
 
 /// The horizontal gap between the day period fragment and the fragment
 /// positioned next to it horizontally.
@@ -1575,12 +1580,25 @@ class _TimePickerDialogState extends State<_TimePickerDialog> {
             ),
           );
 
+          double timePickerHeightPortrait;
+          double timePickerHeightLandscape;
+          switch (theme.materialTapTargetSize) {
+            case MaterialTapTargetSize.padded:
+              timePickerHeightPortrait = _kTimePickerHeightPortrait;
+              timePickerHeightLandscape = _kTimePickerHeightLandscape;
+              break;
+            case MaterialTapTargetSize.shrinkWrap:
+              timePickerHeightPortrait = _kTimePickerHeightPortraitCollapsed;
+              timePickerHeightLandscape = _kTimePickerHeightLandscapeCollapsed;
+              break;
+          }
+
           assert(orientation != null);
           switch (orientation) {
             case Orientation.portrait:
               return new SizedBox(
                 width: _kTimePickerWidthPortrait,
-                height: _kTimePickerHeightPortrait,
+                height: timePickerHeightPortrait,
                 child: new Column(
                   mainAxisSize: MainAxisSize.min,
                   crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -1595,7 +1613,7 @@ class _TimePickerDialogState extends State<_TimePickerDialog> {
             case Orientation.landscape:
               return new SizedBox(
                 width: _kTimePickerWidthLandscape,
-                height: _kTimePickerHeightLandscape,
+                height: timePickerHeightLandscape,
                 child: new Row(
                   mainAxisSize: MainAxisSize.min,
                   crossAxisAlignment: CrossAxisAlignment.stretch,

packages/flutter/lib/src/material/toggleable.dart

@@ -26,10 +26,10 @@ abstract class RenderToggleable extends RenderConstrainedBox {
   RenderToggleable({
     @required bool value,
     bool tristate = false,
-    Size size,
     @required Color activeColor,
     @required Color inactiveColor,
     ValueChanged<bool> onChanged,
+    BoxConstraints additionalConstraints,
     @required TickerProvider vsync,
   }) : assert(tristate != null),
        assert(tristate || value != null),
@@ -42,7 +42,7 @@ abstract class RenderToggleable extends RenderConstrainedBox {
        _inactiveColor = inactiveColor,
        _onChanged = onChanged,
        _vsync = vsync,
-       super(additionalConstraints: new BoxConstraints.tight(size)) {
+       super(additionalConstraints: additionalConstraints) {
     _tap = new TapGestureRecognizer()
       ..onTapDown = _handleTapDown
       ..onTap = _handleTap

packages/flutter/test/material/buttons_test.dart

@@ -39,8 +39,8 @@ void main() {
               SemanticsAction.tap,
             ],
             label: 'ABC',
-            rect: new Rect.fromLTRB(0.0, 0.0, 88.0, 36.0),
-            transform: new Matrix4.translationValues(356.0, 282.0, 0.0),
+            rect: new Rect.fromLTRB(0.0, 0.0, 88.0, 48.0),
+            transform: new Matrix4.translationValues(356.0, 276.0, 0.0),
             flags: <SemanticsFlag>[
               SemanticsFlag.isButton,
               SemanticsFlag.hasEnabledState,
@@ -79,8 +79,8 @@ void main() {
               SemanticsAction.tap,
             ],
             label: 'ABC',
-            rect: new Rect.fromLTRB(0.0, 0.0, 88.0, 36.0),
-            transform: new Matrix4.translationValues(356.0, 282.0, 0.0),
+            rect: new Rect.fromLTRB(0.0, 0.0, 88.0, 48.0),
+            transform: new Matrix4.translationValues(356.0, 276.0, 0.0),
             flags: <SemanticsFlag>[
               SemanticsFlag.isButton,
               SemanticsFlag.hasEnabledState,
@@ -113,7 +113,7 @@ void main() {
       ),
     );
 
-    expect(tester.getSize(find.byType(FlatButton)), equals(const Size(88.0, 36.0)));
+    expect(tester.getSize(find.byType(FlatButton)), equals(const Size(88.0, 48.0)));
     expect(tester.getSize(find.byType(Text)), equals(const Size(42.0, 14.0)));
 
     // textScaleFactor expands text, but not button.
@@ -134,7 +134,7 @@ void main() {
       ),
     );
 
-    expect(tester.getSize(find.byType(FlatButton)), equals(const Size(88.0, 36.0)));
+    expect(tester.getSize(find.byType(FlatButton)), equals(const Size(88.0, 48.0)));
     // Scaled text rendering is different on Linux and Mac by one pixel.
     // TODO(#12357): Update this test when text rendering is fixed.
     expect(tester.getSize(find.byType(Text)).width, isIn(<double>[54.0, 55.0]));
@@ -162,7 +162,7 @@ void main() {
     // Scaled text rendering is different on Linux and Mac by one pixel.
     // TODO(#12357): Update this test when text rendering is fixed.
     expect(tester.getSize(find.byType(FlatButton)).width, isIn(<double>[158.0, 159.0]));
-    expect(tester.getSize(find.byType(FlatButton)).height, equals(42.0));
+    expect(tester.getSize(find.byType(FlatButton)).height, equals(48.0));
     expect(tester.getSize(find.byType(Text)).width, isIn(<double>[126.0, 127.0]));
     expect(tester.getSize(find.byType(Text)).height, equals(42.0));
   });
@@ -187,7 +187,9 @@ void main() {
       new Directionality(
         textDirection: TextDirection.ltr,
         child: new Theme(
-          data: new ThemeData(),
+          data: new ThemeData(
+            materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
+          ),
           child: buttonWidget,
         ),
       ),
@@ -233,6 +235,7 @@ void main() {
           data: new ThemeData(
             highlightColor: themeHighlightColor1,
             splashColor: themeSplashColor1,
+            materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
           ),
           child: buttonWidget,
         ),
@@ -260,6 +263,7 @@ void main() {
           data: new ThemeData(
             highlightColor: themeHighlightColor2,
             splashColor: themeSplashColor2,
+            materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
           ),
           child: buttonWidget, // same widget, so does not get updated because of us
         ),
@@ -279,7 +283,7 @@ void main() {
   testWidgets('Disabled MaterialButton has same semantic size as enabled and exposes disabled semantics', (WidgetTester tester) async {
     final SemanticsTester semantics = new SemanticsTester(tester);
 
-    final Rect expectedButtonSize = new Rect.fromLTRB(0.0, 0.0, 116.0, 36.0);
+    final Rect expectedButtonSize = new Rect.fromLTRB(0.0, 0.0, 116.0, 48.0);
     // Button is in center of screen
     final Matrix4 expectedButtonTransform = new Matrix4.identity()
       ..translate(
@@ -354,4 +358,136 @@ void main() {
 
     semantics.dispose();
   });
+
+  testWidgets('MaterialButton size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
+    final Key key1 = new UniqueKey();
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.padded),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new MaterialButton(
+                key: key1,
+                child: const SizedBox(width: 50.0, height: 8.0),
+                onPressed: () {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key1)), const Size(88.0, 48.0));
+
+    final Key key2 = new UniqueKey();
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new MaterialButton(
+                key: key2,
+                child: const SizedBox(width: 50.0, height: 8.0),
+                onPressed: () {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key2)), const Size(88.0, 36.0));
+  });
+
+  testWidgets('FlatButton size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
+    final Key key1 = new UniqueKey();
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.padded),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new FlatButton(
+                key: key1,
+                child: const SizedBox(width: 50.0, height: 8.0),
+                onPressed: () {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key1)), const Size(88.0, 48.0));
+
+    final Key key2 = new UniqueKey();
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new FlatButton(
+                key: key2,
+                child: const SizedBox(width: 50.0, height: 8.0),
+                onPressed: () {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key2)), const Size(88.0, 36.0));
+  });
+
+  testWidgets('RaisedButton size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
+    final Key key1 = new UniqueKey();
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.padded),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new RaisedButton(
+                key: key1,
+                child: const SizedBox(width: 50.0, height: 8.0),
+                onPressed: () {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key1)), const Size(88.0, 48.0));
+
+    final Key key2 = new UniqueKey();
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new RaisedButton(
+                key: key2,
+                child: const SizedBox(width: 50.0, height: 8.0),
+                onPressed: () {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key2)), const Size(88.0, 36.0));
+  });
 }

packages/flutter/test/material/checkbox_test.dart

@@ -16,13 +16,38 @@ void main() {
     debugResetSemanticsIdCounter();
   });
 
-  testWidgets('Checkbox size is 40x40', (WidgetTester tester) async {
+  testWidgets('Checkbox size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
-          child: new Checkbox(
-            value: false,
-            onChanged: (bool newValue) { },
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.padded),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new Checkbox(
+                value: true,
+                onChanged: (bool newValue) {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byType(Checkbox)), const Size(48.0, 48.0));
+
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new Checkbox(
+                value: true,
+                onChanged: (bool newValue) {},
+              ),
+            ),
           ),
         ),
       ),

packages/flutter/test/material/floating_action_button_test.dart

@@ -67,6 +67,44 @@ void main() {
     expect(find.byType(Text), findsOneWidget);
   });
 
+  testWidgets('FlatActionButton mini size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
+    final Key key1 = new UniqueKey();
+    await tester.pumpWidget(
+      new MaterialApp(
+        home: new Theme(
+          data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.padded),
+          child: new Scaffold(
+            floatingActionButton: new FloatingActionButton(
+              key: key1,
+              mini: true,
+              onPressed: null,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key1)), const Size(48.0, 48.0));
+
+    final Key key2 = new UniqueKey();
+    await tester.pumpWidget(
+      new MaterialApp(
+        home: new Theme(
+          data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
+          child: new Scaffold(
+            floatingActionButton: new FloatingActionButton(
+              key: key2,
+              mini: true,
+              onPressed: null,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key2)), const Size(40.0, 40.0));
+  });
+
   testWidgets('FloatingActionButton.isExtended', (WidgetTester tester) async {
     await tester.pumpWidget(
       new MaterialApp(

packages/flutter/test/material/outline_button_test.dart

@@ -55,7 +55,7 @@ void main() {
       new Directionality(
         textDirection: TextDirection.ltr,
         child: new Theme(
-          data: new ThemeData(),
+          data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
           child: new Container(
             alignment: Alignment.topLeft,
             child: new OutlineButton(
@@ -140,8 +140,8 @@ void main() {
               SemanticsAction.tap,
             ],
             label: 'ABC',
-            rect: new Rect.fromLTRB(0.0, 0.0, 88.0, 36.0),
-            transform: new Matrix4.translationValues(356.0, 282.0, 0.0),
+            rect: new Rect.fromLTRB(0.0, 0.0, 88.0, 48.0),
+            transform: new Matrix4.translationValues(356.0, 276.0, 0.0),
             flags: <SemanticsFlag>[
               SemanticsFlag.isButton,
               SemanticsFlag.hasEnabledState,
@@ -175,7 +175,7 @@ void main() {
       ),
     );
 
-    expect(tester.getSize(find.byType(OutlineButton)), equals(const Size(88.0, 36.0)));
+    expect(tester.getSize(find.byType(OutlineButton)), equals(const Size(88.0, 48.0)));
     expect(tester.getSize(find.byType(Text)), equals(const Size(42.0, 14.0)));
 
     // textScaleFactor expands text, but not button.
@@ -196,7 +196,7 @@ void main() {
       ),
     );
 
-    expect(tester.getSize(find.byType(FlatButton)), equals(const Size(88.0, 36.0)));
+    expect(tester.getSize(find.byType(FlatButton)), equals(const Size(88.0, 48.0)));
     // Scaled text rendering is different on Linux and Mac by one pixel.
     // TODO(#12357): Update this test when text rendering is fixed.
     expect(tester.getSize(find.byType(Text)).width, isIn(<double>[54.0, 55.0]));
@@ -224,7 +224,7 @@ void main() {
     // Scaled text rendering is different on Linux and Mac by one pixel.
     // TODO(#12357): Update this test when text rendering is fixed.
     expect(tester.getSize(find.byType(FlatButton)).width, isIn(<double>[158.0, 159.0]));
-    expect(tester.getSize(find.byType(FlatButton)).height, equals(42.0));
+    expect(tester.getSize(find.byType(FlatButton)).height, equals(48.0));
     expect(tester.getSize(find.byType(Text)).width, isIn(<double>[126.0, 127.0]));
     expect(tester.getSize(find.byType(Text)).height, equals(42.0));
   });

packages/flutter/test/material/radio_test.dart

@@ -64,23 +64,50 @@ void main() {
     expect(log, isEmpty);
   });
 
-  testWidgets('Radio size is 40x40', (WidgetTester tester) async {
-    final Key key = new UniqueKey();
+  testWidgets('Radio size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
+    final Key key1 = new UniqueKey();
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.padded),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new Radio<bool>(
+                key: key1,
+                groupValue: true,
+                value: true,
+                onChanged: (bool newValue) {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byKey(key1)), const Size(48.0, 48.0));
 
+    final Key key2 = new UniqueKey();
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
-          child: new Radio<int>(
-            key: key,
-            value: 1,
-            groupValue: 2,
-            onChanged: (int newValue) { },
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new Radio<bool>(
+                key: key2,
+                groupValue: true,
+                value: true,
+                onChanged: (bool newValue) {},
+              ),
+            ),
           ),
         ),
       ),
     );
 
-    expect(tester.getSize(find.byKey(key)), const Size(40.0, 40.0));
+    expect(tester.getSize(find.byKey(key2)), const Size(40.0, 40.0));
   });
 
 

packages/flutter/test/material/raw_material_button_test.dart

@@ -2,10 +2,11 @@ import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../rendering/mock_canvas.dart';
 import '../widgets/semantics_tester.dart';
 
 void main() {
-  testWidgets('outerPadding expands hit test area', (WidgetTester tester) async {
+  testWidgets('materialTapTargetSize.padded expands hit test area', (WidgetTester tester) async {
     int pressed = 0;
 
     await tester.pumpWidget(new RawMaterialButton(
@@ -13,23 +14,23 @@ void main() {
         pressed++;
       },
       constraints: new BoxConstraints.tight(const Size(10.0, 10.0)),
-      outerPadding: const EdgeInsets.all(50.0),
+      materialTapTargetSize: MaterialTapTargetSize.padded,
       child: const Text('+', textDirection: TextDirection.ltr),
     ));
 
-    await tester.tapAt(const Offset(100.0, 100.0));
+    await tester.tapAt(const Offset(40.0, 400.0));
 
     expect(pressed, 1);
   });
 
-  testWidgets('outerPadding expands semantics area', (WidgetTester tester) async {
+  testWidgets('materialTapTargetSize.padded expands semantics area', (WidgetTester tester) async {
     final SemanticsTester semantics = new SemanticsTester(tester);
     await tester.pumpWidget(
       new Center(
         child: new RawMaterialButton(
           onPressed: () {},
           constraints: new BoxConstraints.tight(const Size(10.0, 10.0)),
-          outerPadding: const EdgeInsets.all(50.0),
+          materialTapTargetSize: MaterialTapTargetSize.padded,
           child: const Text('+', textDirection: TextDirection.ltr),
         ),
       ),
@@ -50,7 +51,7 @@ void main() {
           ],
           label: '+',
           textDirection: TextDirection.ltr,
-          rect: Rect.fromLTRB(0.0, 0.0, 110.0, 110.0),
+          rect: Rect.fromLTRB(0.0, 0.0, 48.0, 48.0),
           children: <TestSemantics>[],
         ),
       ]
@@ -58,4 +59,57 @@ void main() {
 
     semantics.dispose();
   });
+
+  testWidgets('Ink splash from center tap originates in correct location', (WidgetTester tester) async {
+    const Color highlightColor = const Color(0xAAFF0000);
+    const Color splashColor = const Color(0xAA0000FF);
+    const Color fillColor = const Color(0xFFEF5350);
+
+    await tester.pumpWidget(
+      new RawMaterialButton(
+        materialTapTargetSize: MaterialTapTargetSize.padded,
+        onPressed: () {},
+        fillColor: fillColor,
+        highlightColor: highlightColor,
+        splashColor: splashColor,
+        child: const SizedBox(),
+      )
+    );
+
+    final Offset center = tester.getCenter(find.byType(InkWell));
+    final TestGesture gesture = await tester.startGesture(center);
+    await tester.pump(); // start gesture
+    await tester.pump(const Duration(milliseconds: 200)); // wait for splash to be well under way
+
+    final RenderBox box = Material.of(tester.element(find.byType(InkWell))) as dynamic;
+    // centered in material button.
+    expect(box, paints..circle(x: 44.0, y: 18.0, color: splashColor));
+    await gesture.up();
+  });
+
+  testWidgets('Ink splash from tap above material originates in correct location', (WidgetTester tester) async {
+    const Color highlightColor = const Color(0xAAFF0000);
+    const Color splashColor = const Color(0xAA0000FF);
+    const Color fillColor = const Color(0xFFEF5350);
+
+    await tester.pumpWidget(
+      new RawMaterialButton(
+        materialTapTargetSize: MaterialTapTargetSize.padded,
+        onPressed: () {},
+        fillColor: fillColor,
+        highlightColor: highlightColor,
+        splashColor: splashColor,
+        child: const SizedBox(),
+      )
+    );
+
+    final Offset top = tester.getRect(find.byType(InkWell)).topCenter;
+    final TestGesture gesture = await tester.startGesture(top);
+    await tester.pump(); // start gesture
+    await tester.pump(const Duration(milliseconds: 200)); // wait for splash to be well under way
+    final RenderBox box = Material.of(tester.element(find.byType(InkWell))) as dynamic;
+    // paints above above material
+    expect(box, paints..circle(x: 44.0, y: 0.0, color: splashColor));
+    await gesture.up();
+  });
 }
\ No newline at end of file

packages/flutter/test/material/scaffold_test.dart

@@ -542,7 +542,7 @@ void main() {
           ),
         ),
       ));
-      expect(tester.element(find.byKey(testKey)).size, const Size(88.0, 36.0));
+      expect(tester.element(find.byKey(testKey)).size, const Size(88.0, 48.0));
       expect(tester.renderObject<RenderBox>(find.byKey(testKey)).localToGlobal(Offset.zero), const Offset(0.0, 0.0));
     });
   });

packages/flutter/test/material/snack_bar_test.dart

@@ -341,10 +341,10 @@ void main() {
     final Offset snackBarBottomRight = snackBarBox.localToGlobal(snackBarBox.size.bottomRight(Offset.zero));
 
     expect(textBottomLeft.dx - snackBarBottomLeft.dx, 24.0 + 10.0); // margin + left padding
-    expect(snackBarBottomLeft.dy - textBottomLeft.dy, 14.0 + 40.0); // margin + bottom padding
+    expect(snackBarBottomLeft.dy - textBottomLeft.dy, 17.0 + 40.0); // margin + bottom padding
     expect(actionTextBottomLeft.dx - textBottomRight.dx, 24.0);
     expect(snackBarBottomRight.dx - actionTextBottomRight.dx, 24.0 + 30.0); // margin + right padding
-    expect(snackBarBottomRight.dy - actionTextBottomRight.dy, 14.0 + 40.0); // margin + bottom padding
+    expect(snackBarBottomRight.dy - actionTextBottomRight.dy, 17.0 + 40.0); // margin + bottom padding
   });
 
   testWidgets('SnackBar is positioned above BottomNavigationBar', (WidgetTester tester) async {
@@ -398,10 +398,10 @@ void main() {
     final Offset snackBarBottomRight = snackBarBox.localToGlobal(snackBarBox.size.bottomRight(Offset.zero));
 
     expect(textBottomLeft.dx - snackBarBottomLeft.dx, 24.0 + 10.0); // margin + left padding
-    expect(snackBarBottomLeft.dy - textBottomLeft.dy, 14.0); // margin (with no bottom padding)
+    expect(snackBarBottomLeft.dy - textBottomLeft.dy, 17.0); // margin (with no bottom padding)
     expect(actionTextBottomLeft.dx - textBottomRight.dx, 24.0);
     expect(snackBarBottomRight.dx - actionTextBottomRight.dx, 24.0 + 30.0); // margin + right padding
-    expect(snackBarBottomRight.dy - actionTextBottomRight.dy, 14.0); // margin (with no bottom padding)
+    expect(snackBarBottomRight.dy - actionTextBottomRight.dy, 17.0); // margin (with no bottom padding)
   });
 
   testWidgets('SnackBarClosedReason', (WidgetTester tester) async {

packages/flutter/test/material/switch_test.dart

@@ -43,6 +43,46 @@ void main() {
     expect(value, isTrue);
   });
 
+  testWidgets('Switch size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.padded),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new Switch(
+                value: true,
+                onChanged: (bool newValue) {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byType(Switch)), const Size(59.0, 48.0));
+
+    await tester.pumpWidget(
+      new Theme(
+        data: new ThemeData(materialTapTargetSize: MaterialTapTargetSize.shrinkWrap),
+        child: new Directionality(
+          textDirection: TextDirection.ltr,
+          child: new Material(
+            child: new Center(
+              child: new Switch(
+                value: true,
+                onChanged: (bool newValue) {},
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(tester.getSize(find.byType(Switch)), const Size(59.0, 40.0));
+  });
+
   testWidgets('Switch can drag (LTR)', (WidgetTester tester) async {
     bool value = false;
 

packages/flutter/test/material/theme_data_test.dart

@@ -103,6 +103,12 @@ void main() {
     expect(darkTheme.accentTextTheme.title.color, typography.white.title.color);
   });
 
+  test('Defaults to MaterialTapTargetBehavior.expanded', () {
+    final ThemeData themeData = new ThemeData();
+
+    expect(themeData.materialTapTargetSize, MaterialTapTargetSize.padded);
+  });
+
   test('Can control fontFamily', () {
     final ThemeData themeData = new ThemeData(fontFamily: 'Ahem');