Remove a number of old scrolling widgets: (#8212)

- ScrollableList
 - ScrollableLazyList
 - LazyBlock
 - MaterialList

Clients should use ListView instead.

examples/flutter_gallery/lib/demo/overscroll_demo.dart

@@ -45,8 +45,7 @@ class OverscrollDemoState extends State<OverscrollDemo> {
 
   @override
   Widget build(BuildContext context) {
-    Widget body = new MaterialList( // ignore: DEPRECATED_MEMBER_USE
-      type: MaterialListType.threeLine,
+    Widget body = new Block( // ignore: DEPRECATED_MEMBER_USE
       padding: const EdgeInsets.all(8.0),
       scrollableKey: _scrollableKey,
       children: _items.map((String item) {
@@ -56,7 +55,7 @@ class OverscrollDemoState extends State<OverscrollDemo> {
           title: new Text('This item represents $item.'),
           subtitle: new Text('Even more additional list item information appears on line three.')
         );
-      })
+      }).toList(),
     );
 
     String  indicatorTypeText;

packages/flutter/lib/material.dart

@@ -53,7 +53,6 @@ export 'src/material/ink_highlight.dart';
 export 'src/material/ink_splash.dart';
 export 'src/material/ink_well.dart';
 export 'src/material/input.dart';
-export 'src/material/list.dart';
 export 'src/material/list_item.dart';
 export 'src/material/material.dart';
 export 'src/material/mergeable_material.dart';

packages/flutter/lib/rendering.dart

@@ -34,7 +34,6 @@ export 'src/rendering/flex.dart';
 export 'src/rendering/flow.dart';
 export 'src/rendering/image.dart';
 export 'src/rendering/layer.dart';
-export 'src/rendering/list.dart';
 export 'src/rendering/node.dart';
 export 'src/rendering/object.dart';
 export 'src/rendering/paragraph.dart';

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

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'package:flutter/widgets.dart';
-
-/// The kind of list items contained in a material design list.
-///
-/// See also:
-///
-///  * [ListItem]
-///  * [kListItemExtent]
-///  * <https://material.google.com/components/lists.html#lists-specs>
-enum MaterialListType {
-  /// A list item that contains a single line of text.
-  oneLine,
-
-  /// A list item that contains a [CircleAvatar] followed by a single line of text.
-  oneLineWithAvatar,
-
-  /// A list item that contains two lines of text.
-  twoLine,
-
-  /// A list item that contains three lines of text.
-  threeLine
-}
-
-/// The vertical extent of the different types of material list items.
-///
-/// See also:
-///
-///  * [MaterialListType]
-///  * [ListItem]
-///  * [kListItemExtent]
-///  * <https://material.google.com/components/lists.html#lists-specs>
-Map<MaterialListType, double> kListItemExtent = const <MaterialListType, double>{
-  MaterialListType.oneLine: 48.0,
-  MaterialListType.oneLineWithAvatar: 56.0,
-  MaterialListType.twoLine: 72.0,
-  MaterialListType.threeLine: 88.0,
-};
-
-/// A scrollable list containing material list items.
-///
-/// Material list configures a [ScrollableList] with a number of default values
-/// to match material design.
-///
-/// See also:
-///
-///  * [SliverList], which shows heterogeneous widgets in a list and makes the
-///    list scrollable if necessary.
-///  * [ListItem], to show content in a [MaterialList] using material design
-///    conventions.
-///  * [ScrollableList], on which this widget is based.
-///  * [TwoLevelList], for lists that have subsections that can collapse and
-///    expand.
-///  * [GridView]
-///  * <https://material.google.com/components/lists.html>
-@Deprecated('use ListView instead')
-class MaterialList extends StatelessWidget {
-  /// Creates a material list.
-  ///
-  /// By default, has a type of [MaterialListType.twoLine].
-  MaterialList({
-    Key key,
-    this.initialScrollOffset,
-    this.onScrollStart,
-    this.onScroll,
-    this.onScrollEnd,
-    this.type: MaterialListType.twoLine,
-    this.children: const <Widget>[],
-    this.padding: EdgeInsets.zero,
-    this.scrollableKey
-  }) : super(key: key);
-
-  /// The scroll offset this widget should use when first created.
-  final double initialScrollOffset;
-
-  /// Called whenever this widget starts to scroll.
-  final ScrollListener onScrollStart;
-
-  /// Called whenever this widget's scroll offset changes.
-  final ScrollListener onScroll;
-
-  /// Called whenever this widget stops scrolling.
-  final ScrollListener onScrollEnd;
-
-  /// The kind of [ListItem] contained in this list.
-  final MaterialListType type;
-
-  /// The widgets to display in this list.
-  final Iterable<Widget> children;
-
-  /// The amount of space by which to inset the children inside the viewport.
-  final EdgeInsets padding;
-
-  /// The key to use for the underlying scrollable widget.
-  final Key scrollableKey;
-
-  @override
-  Widget build(BuildContext context) {
-    return new ScrollableList(
-      scrollableKey: scrollableKey,
-      initialScrollOffset: initialScrollOffset,
-      scrollDirection: Axis.vertical,
-      onScrollStart: onScrollStart,
-      onScroll: onScroll,
-      onScrollEnd: onScrollEnd,
-      itemExtent: kListItemExtent[type],
-      padding: const EdgeInsets.symmetric(vertical: 8.0) + padding,
-      children: children,
-    );
-  }
-}

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

@@ -10,6 +10,42 @@ import 'debug.dart';
 import 'ink_well.dart';
 import 'theme.dart';
 
+/// The kind of list items contained in a material design list.
+///
+/// See also:
+///
+///  * [ListItem]
+///  * [kListItemExtent]
+///  * <https://material.google.com/components/lists.html#lists-specs>
+enum MaterialListType {
+  /// A list item that contains a single line of text.
+  oneLine,
+
+  /// A list item that contains a [CircleAvatar] followed by a single line of text.
+  oneLineWithAvatar,
+
+  /// A list item that contains two lines of text.
+  twoLine,
+
+  /// A list item that contains three lines of text.
+  threeLine
+}
+
+/// The vertical extent of the different types of material list items.
+///
+/// See also:
+///
+///  * [MaterialListType]
+///  * [ListItem]
+///  * [kListItemExtent]
+///  * <https://material.google.com/components/lists.html#lists-specs>
+Map<MaterialListType, double> kListItemExtent = const <MaterialListType, double>{
+  MaterialListType.oneLine: 48.0,
+  MaterialListType.oneLineWithAvatar: 56.0,
+  MaterialListType.twoLine: 72.0,
+  MaterialListType.threeLine: 88.0,
+};
+
 /// A single row typically containing an icon and some text.
 ///
 /// List items are one to three lines of text optionally flanked by icons or
@@ -32,7 +68,7 @@ import 'theme.dart';
 ///
 /// See also:
 ///
-///  * [MaterialList], which takes a list of [ListItem] widgets and shows them
+///  * [ListView], which takes a list of [ListItem] widgets and shows them
 ///    as a scrolling list.
 ///  * [Card], which can be used with [Column] to show a few [ListItem]s.
 ///  * [CircleAvatar], which shows an icon representing a person.

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

@@ -10,7 +10,6 @@ import 'icon.dart';
 import 'icons.dart';
 import 'icon_theme.dart';
 import 'icon_theme_data.dart';
-import 'list.dart';
 import 'list_item.dart';
 import 'theme.dart';
 import 'theme_data.dart';

packages/flutter/lib/src/rendering/list.dart

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'dart:math' as math;
-
-import 'box.dart';
-import 'object.dart';
-import 'viewport.dart';
-
-/// Parent data for use with [RenderList].
-class ListParentData extends ContainerBoxParentDataMixin<RenderBox> { }
-
-/// A linear layout of children intended for use as a virtual viewport.
-///
-/// Children are layout out in order along the main axis. If [itemExtent] is
-/// non-null, each child is required to have exactly [itemExtent] extent in the
-/// main axis. If [itemExtent] is null, each child is required to have the same
-/// extent in the main axis as the list itself.
-///
-/// In the cross axis, the render list expands to fill the available space and
-/// each child is required to have the same extent in the cross axis as the list
-/// itself.
-class RenderList extends RenderVirtualViewport<ListParentData> {
-  /// Creates a render list.
-  ///
-  /// By default, the list is oriented vertically and anchored at the start.
-  RenderList({
-    List<RenderBox> children,
-    double itemExtent,
-    EdgeInsets padding,
-    int virtualChildCount,
-    Offset paintOffset: Offset.zero,
-    Axis mainAxis: Axis.vertical,
-    ViewportAnchor anchor: ViewportAnchor.start,
-    LayoutCallback<BoxConstraints> callback
-  }) : _itemExtent = itemExtent,
-       _padding = padding,
-       super(
-         virtualChildCount: virtualChildCount,
-         paintOffset: paintOffset,
-         mainAxis: mainAxis,
-         anchor: anchor,
-         callback: callback
-       ) {
-    addAll(children);
-  }
-
-  /// The main-axis extent of each item in the list.
-  ///
-  /// If [itemExtent] is null, the items are required to match the main-axis
-  /// extent of the list itself.
-  double get itemExtent => _itemExtent;
-  double _itemExtent;
-  set itemExtent (double newValue) {
-    if (_itemExtent == newValue)
-      return;
-    _itemExtent = newValue;
-    markNeedsLayout();
-  }
-
-  /// The amount of space by which to inset the children inside the list.
-  EdgeInsets get padding => _padding;
-  EdgeInsets _padding;
-  set padding (EdgeInsets newValue) {
-    if (_padding == newValue)
-      return;
-    _padding = newValue;
-    markNeedsLayout();
-  }
-
-  @override
-  void setupParentData(RenderBox child) {
-    if (child.parentData is! ListParentData)
-      child.parentData = new ListParentData();
-  }
-
-  double get _preferredExtent {
-    if (itemExtent == null)
-      return double.INFINITY;
-    final int count = virtualChildCount;
-    if (count == null)
-      return double.INFINITY;
-    double extent = itemExtent * count;
-    if (padding != null)
-      extent += padding.along(mainAxis);
-    return extent;
-  }
-
-  double _computeIntrinsicWidth() {
-    switch (mainAxis) {
-      case Axis.vertical:
-        assert(debugThrowIfNotCheckingIntrinsics());
-        return 0.0;
-      case Axis.horizontal:
-        final double width = _preferredExtent;
-        if (width.isFinite)
-          return width;
-        assert(debugThrowIfNotCheckingIntrinsics());
-        return 0.0;
-    }
-    assert(mainAxis != null);
-    return null;
-  }
-
-  @override
-  double computeMinIntrinsicWidth(double height) {
-    return _computeIntrinsicWidth();
-  }
-
-  @override
-  double computeMaxIntrinsicWidth(double height) {
-    return _computeIntrinsicWidth();
-  }
-
-  double _computeIntrinsicHeight() {
-    switch (mainAxis) {
-      case Axis.vertical:
-        final double height = _preferredExtent;
-        if (height.isFinite)
-          return height;
-        assert(debugThrowIfNotCheckingIntrinsics());
-        return 0.0;
-      case Axis.horizontal:
-        assert(debugThrowIfNotCheckingIntrinsics());
-        return 0.0;
-    }
-    assert(mainAxis != null);
-    return null;
-  }
-
-  @override
-  double computeMinIntrinsicHeight(double width) {
-    return _computeIntrinsicHeight();
-  }
-
-  @override
-  double computeMaxIntrinsicHeight(double width) {
-    return _computeIntrinsicHeight();
-  }
-
-  @override
-  void performLayout() {
-    switch (mainAxis) {
-      case Axis.vertical:
-        size = new Size(constraints.maxWidth,
-                        constraints.constrainHeight(_preferredExtent));
-        break;
-      case Axis.horizontal:
-        size = new Size(constraints.constrainWidth(_preferredExtent),
-                        constraints.maxHeight);
-        break;
-    }
-
-    if (callback != null)
-      invokeLayoutCallback<BoxConstraints>(callback);
-
-    double itemWidth;
-    double itemHeight;
-
-    double x = 0.0;
-    double dx = 0.0;
-
-    double y = 0.0;
-    double dy = 0.0;
-
-    switch (mainAxis) {
-      case Axis.vertical:
-        itemWidth = math.max(0.0, size.width - (padding == null ? 0.0 : padding.horizontal));
-        itemHeight = itemExtent ?? size.height;
-        x = padding != null ? padding.left : 0.0;
-        dy = itemHeight;
-        break;
-      case Axis.horizontal:
-        itemWidth = itemExtent ?? size.width;
-        itemHeight = math.max(0.0, size.height - (padding == null ? 0.0 : padding.vertical));
-        y = padding != null ? padding.top : 0.0;
-        dx = itemWidth;
-        break;
-    }
-
-    BoxConstraints innerConstraints =
-        new BoxConstraints.tightFor(width: itemWidth, height: itemHeight);
-
-    RenderBox child = firstChild;
-    while (child != null) {
-      child.layout(innerConstraints);
-
-      final ListParentData childParentData = child.parentData;
-      childParentData.offset = new Offset(x, y);
-      x += dx;
-      y += dy;
-
-      assert(child.parentData == childParentData);
-      child = childParentData.nextSibling;
-    }
-  }
-}

packages/flutter/lib/src/rendering/object.dart

@@ -1452,12 +1452,6 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
     });
     return result;
   }
-  @Deprecated(
-    'If you are using needsLayout for an assert, switch to debugNeedsLayout. '
-    'If you are using it for actual runtime logic, please contact the Flutter '
-    'team to let us know what your use case is. We intend to remove this getter.'
-  )
-  bool get needsLayout => _needsLayout;
   bool _needsLayout = true;
 
   RenderObject _relayoutBoundary;

packages/flutter/lib/src/rendering/viewport.dart

@@ -4,7 +4,6 @@
 
 import 'dart:ui' as ui show window;
 
-import 'package:flutter/foundation.dart';
 import 'package:vector_math/vector_math_64.dart';
 
 import 'box.dart';
@@ -337,132 +336,3 @@ class RenderViewport extends RenderViewportBase with RenderObjectWithChildMixin<
     return false;
   }
 }
-
-/// A render object that shows a subset of its children.
-///
-/// The children of a viewport can layout to a larger size along the viewport's
-/// [mainAxis] than the viewport itself. If that happens, only a subset of the
-/// children will be visible through the viewport. The subset of children that
-/// are visible can be controlled with the [paintOffset].
-///
-/// See also:
-///
-///  * [RenderList] (which arranges its children linearly)
-///  * [RenderGrid] (which arranges its children into tiles)
-///  * [RenderViewport] (which is easier to use with a single child)
-abstract class RenderVirtualViewport<T extends ContainerBoxParentDataMixin<RenderBox>>
-    extends RenderViewportBase with ContainerRenderObjectMixin<RenderBox, T>,
-                                    RenderBoxContainerDefaultsMixin<RenderBox, T> {
-  /// Initializes fields for subclasses.
-  ///
-  /// The [paintOffset] and [mainAxis] arguments must not be null.
-  RenderVirtualViewport({
-    int virtualChildCount,
-    LayoutCallback<BoxConstraints> callback,
-    Offset paintOffset: Offset.zero,
-    Axis mainAxis: Axis.vertical,
-    ViewportAnchor anchor: ViewportAnchor.start
-  }) : _virtualChildCount = virtualChildCount,
-       _callback = callback,
-       super(paintOffset, mainAxis, anchor);
-
-  /// The overall number of children this viewport could potentially display.
-  ///
-  /// If null, the viewport might display an unbounded number of children.
-  int get virtualChildCount => _virtualChildCount;
-  int _virtualChildCount;
-  set virtualChildCount(int value) {
-    if (_virtualChildCount == value)
-      return;
-    _virtualChildCount = value;
-    markNeedsLayout();
-  }
-
-  /// Called during [layout] to determine the render object's children.
-  ///
-  /// Typically the callback will mutate the child list appropriately, for
-  /// example so the child list contains only visible children.
-  LayoutCallback<BoxConstraints> get callback => _callback;
-  LayoutCallback<BoxConstraints> _callback;
-  set callback(LayoutCallback<BoxConstraints> value) {
-    if (value == _callback)
-      return;
-    _callback = value;
-    markNeedsLayout();
-  }
-
-  /// Throws an exception if asserts are enabled, unless the
-  /// [RenderObject.debugCheckingIntrinsics] flag is set.
-  ///
-  /// This is a convenience function for subclasses to call from their
-  /// intrinsic-sizing functions if they don't have a good way to generate the
-  /// numbers.
-  @protected
-  bool debugThrowIfNotCheckingIntrinsics() {
-    assert(() {
-      if (!RenderObject.debugCheckingIntrinsics) {
-        throw new FlutterError(
-          '$runtimeType does not support returning intrinsic dimensions.\n'
-          'Calculating the intrinsic dimensions would require walking the entire '
-          'child list, which cannot reliably and efficiently be done for render '
-          'objects that potentially generate their child list during layout.'
-        );
-      }
-      return true;
-    });
-    return true;
-  }
-
-  @override
-  double computeMinIntrinsicWidth(double height) {
-    assert(debugThrowIfNotCheckingIntrinsics());
-    return 0.0;
-  }
-
-  @override
-  double computeMaxIntrinsicWidth(double height) {
-    assert(debugThrowIfNotCheckingIntrinsics());
-    return 0.0;
-  }
-
-  @override
-  double computeMinIntrinsicHeight(double width) {
-    assert(debugThrowIfNotCheckingIntrinsics());
-    return 0.0;
-  }
-
-  @override
-  double computeMaxIntrinsicHeight(double width) {
-    assert(debugThrowIfNotCheckingIntrinsics());
-    return 0.0;
-  }
-
-  @override
-  bool hitTestChildren(HitTestResult result, { Point position }) {
-    return defaultHitTestChildren(result, position: position + -_effectivePaintOffset);
-  }
-
-  void _paintContents(PaintingContext context, Offset offset) {
-    defaultPaint(context, offset + _effectivePaintOffset);
-  }
-
-  @override
-  void paint(PaintingContext context, Offset offset) {
-    context.pushClipRect(needsCompositing, offset, Point.origin & size, _paintContents);
-  }
-
-  @override
-  Rect describeApproximatePaintClip(RenderObject child) => Point.origin & size;
-
-  // Workaround for https://github.com/dart-lang/sdk/issues/25232
-  @override
-  void applyPaintTransform(RenderBox child, Matrix4 transform) {
-    super.applyPaintTransform(child, transform);
-  }
-
-  @override
-  void debugFillDescription(List<String> description) {
-    super.debugFillDescription(description);
-    description.add('virtual child count: $virtualChildCount');
-  }
-}

packages/flutter/lib/widgets.dart

@@ -29,7 +29,6 @@ export 'src/widgets/heroes.dart';
 export 'src/widgets/image.dart';
 export 'src/widgets/implicit_animations.dart';
 export 'src/widgets/layout_builder.dart';
-export 'src/widgets/lazy_block.dart';
 export 'src/widgets/locale_query.dart';
 export 'src/widgets/media_query.dart';
 export 'src/widgets/modal_barrier.dart';
@@ -55,7 +54,6 @@ export 'src/widgets/scroll_position.dart';
 export 'src/widgets/scroll_simulation.dart';
 export 'src/widgets/scroll_view.dart';
 export 'src/widgets/scrollable.dart';
-export 'src/widgets/scrollable_list.dart';
 export 'src/widgets/semantics_debugger.dart';
 export 'src/widgets/single_child_scroll_view.dart';
 export 'src/widgets/size_changed_layout_notifier.dart';
@@ -70,6 +68,5 @@ export 'src/widgets/title.dart';
 export 'src/widgets/transitions.dart';
 export 'src/widgets/unique_widget.dart';
 export 'src/widgets/viewport.dart';
-export 'src/widgets/virtual_viewport.dart';
 
 export 'package:vector_math/vector_math_64.dart' show Matrix4;