Fix DatePicker (#5061)

Fundamentally the core problem was that we were not saying how wide a
date picker should be. It should be 330 pixels, if I'm measuring the
spec's mocks correctly.

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

@@ -118,8 +118,7 @@ class _DatePickerState extends State<DatePicker> {
         );
         break;
     }
-    return new Column(
-      crossAxisAlignment: CrossAxisAlignment.stretch,
+    return new BlockBody(
       children: <Widget>[
         header,
         new Container(
@@ -213,7 +212,6 @@ const double _kMaxDayPickerHeight = _kDayPickerRowHeight * (_kMaxDayPickerRowCou
 class _DayPickerGridDelegate extends GridDelegateWithInOrderChildPlacement {
   @override
   GridSpecification getGridSpecification(BoxConstraints constraints, int childCount) {
-    assert(constraints.maxWidth < double.INFINITY);
     final int columnCount = DateTime.DAYS_PER_WEEK;
     return new GridSpecification.fromRegularTiles(
       tileWidth: constraints.maxWidth / columnCount,
@@ -459,7 +457,9 @@ class _MonthPickerState extends State<MonthPicker> {
 
   @override
   Widget build(BuildContext context) {
-    return new Stack(
+    return new SizedBox(
+      width: 330.0,
+      child: new Stack(
         children: <Widget>[
           new PageableLazyList(
             key: _dayPickerListKey,
@@ -487,6 +487,7 @@ class _MonthPickerState extends State<MonthPicker> {
             )
           )
         ]
+      )
     );
   }
 

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

@@ -33,7 +33,7 @@ class TimeOfDay {
   ///
   /// The [hour] argument must be between 0 and 23, inclusive. The [minute]
   /// argument must be between 0 and 59, inclusive.
-  const TimeOfDay({ this.hour, this.minute });
+  const TimeOfDay({ @required this.hour, @required this.minute });
 
   /// Returns a new TimeOfDay with the hour and/or minute replaced.
   TimeOfDay replacing({ int hour, int minute }) {
@@ -42,7 +42,7 @@ class TimeOfDay {
     return new TimeOfDay(hour: hour ?? this.hour, minute: minute ?? this.minute);
   }
 
-  /// The selected hour, in 24 hour time from 0..23
+  /// The selected hour, in 24 hour time from 0..23.
   final int hour;
 
   /// The selected minute.

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

@@ -197,6 +197,8 @@ class RenderConstrainedBox extends RenderProxyBox {
 
   @override
   double computeMinIntrinsicWidth(double height) {
+    if (_additionalConstraints.hasBoundedWidth && _additionalConstraints.hasTightWidth)
+      return _additionalConstraints.minWidth;
     final double width = super.computeMinIntrinsicWidth(height);
     if (_additionalConstraints.hasBoundedWidth)
       return _additionalConstraints.constrainWidth(width);
@@ -205,6 +207,8 @@ class RenderConstrainedBox extends RenderProxyBox {
 
   @override
   double computeMaxIntrinsicWidth(double height) {
+    if (_additionalConstraints.hasBoundedWidth && _additionalConstraints.hasTightWidth)
+      return _additionalConstraints.minWidth;
     final double width = super.computeMaxIntrinsicWidth(height);
     if (_additionalConstraints.hasBoundedWidth)
       return _additionalConstraints.constrainWidth(width);
@@ -213,6 +217,8 @@ class RenderConstrainedBox extends RenderProxyBox {
 
   @override
   double computeMinIntrinsicHeight(double width) {
+    if (_additionalConstraints.hasBoundedHeight && _additionalConstraints.hasTightHeight)
+      return _additionalConstraints.minHeight;
     final double height = super.computeMinIntrinsicHeight(width);
     if (_additionalConstraints.hasBoundedHeight)
       return _additionalConstraints.constrainHeight(height);
@@ -221,6 +227,8 @@ class RenderConstrainedBox extends RenderProxyBox {
 
   @override
   double computeMaxIntrinsicHeight(double width) {
+    if (_additionalConstraints.hasBoundedHeight && _additionalConstraints.hasTightHeight)
+      return _additionalConstraints.minHeight;
     final double height = super.computeMaxIntrinsicHeight(width);
     if (_additionalConstraints.hasBoundedHeight)
       return _additionalConstraints.constrainHeight(height);

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

@@ -400,7 +400,7 @@ abstract class RenderVirtualViewport<T extends ContainerBoxParentDataMixin<Rende
     assert(() {
       if (!RenderObject.debugCheckingIntrinsics) {
         throw new FlutterError(
-          'RenderVirtualViewport does not support returning intrinsic dimensions.\n'
+          '$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.'

packages/flutter/test/material/date_picker_test.dart

+// Copyright 2016 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/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('tap-select an day', (WidgetTester tester) async {
+    Key _datePickerKey = new UniqueKey();
+    DateTime _selectedDate = new DateTime(2016, DateTime.JULY, 26);
+
+    await tester.pumpWidget(
+      new Overlay(
+        initialEntries: <OverlayEntry>[
+          new OverlayEntry(
+            builder: (BuildContext context) => new StatefulBuilder(
+              builder: (BuildContext context, StateSetter setState) {
+                return new Positioned(
+                  width: 400.0,
+                  child: new Block(
+                    children: <Widget>[
+                      new Material(
+                        child: new DatePicker(
+                          firstDate: new DateTime(0),
+                          lastDate: new DateTime(9999),
+                          key: _datePickerKey,
+                          selectedDate: _selectedDate,
+                          onChanged: (DateTime value) {
+                            setState(() {
+                              _selectedDate = value;
+                            });
+                          }
+                        )
+                      )
+                    ]
+                  )
+                );
+              }
+            )
+          )
+        ]
+      )
+    );
+
+    await tester.tapAt(const Point(50.0, 200.0));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 26)));
+    await tester.pump(const Duration(seconds: 2));
+
+    await tester.tapAt(const Point(300.0, 200.0));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 1)));
+    await tester.pump(const Duration(seconds: 2));
+
+    await tester.tapAt(const Point(380.0, 120.0));
+    await tester.pump();
+    await tester.pump(const Duration(seconds: 2));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 1)));
+
+    await tester.tapAt(const Point(300.0, 200.0));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.AUGUST, 5)));
+    await tester.pump(const Duration(seconds: 2));
+
+    await tester.scroll(find.byKey(_datePickerKey), const Offset(-300.0, 0.0));
+    await tester.pump();
+    await tester.pump(const Duration(seconds: 2));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.AUGUST, 5)));
+
+    await tester.tapAt(const Point(45.0, 370.0));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.SEPTEMBER, 25)));
+    await tester.pump(const Duration(seconds: 2));
+
+    await tester.scroll(find.byKey(_datePickerKey), const Offset(300.0, 10.0));
+    await tester.pump();
+    await tester.pump(const Duration(seconds: 2));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.SEPTEMBER, 25)));
+
+    await tester.tapAt(const Point(210.0, 280.0));
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.AUGUST, 17)));
+    await tester.pump(const Duration(seconds: 2));
+
+  });
+
+  testWidgets('render picker with intrinsic dimensions', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new Overlay(
+        initialEntries: <OverlayEntry>[
+          new OverlayEntry(
+            builder: (BuildContext context) => new StatefulBuilder(
+              builder: (BuildContext context, StateSetter setState) {
+                return new IntrinsicWidth(
+                  child: new IntrinsicHeight(
+                    child: new Material(
+                      child: new Block(
+                        children: <Widget>[
+                          new DatePicker(
+                            firstDate: new DateTime(0),
+                            lastDate: new DateTime(9999),
+                            onChanged: null,
+                            selectedDate: new DateTime(2000, DateTime.JANUARY, 1)
+                          )
+                        ]
+                      )
+                    )
+                  )
+                );
+              }
+            )
+          )
+        ]
+      )
+    );
+    await tester.pump(const Duration(seconds: 5));
+  });
+
+}

packages/flutter/test/material/time_picker_test.dart

@@ -56,6 +56,20 @@ void main() {
     await tester.pump(const Duration(seconds: 1)); // Finish settling animation.
   });
 
+  testWidgets('render picker with intrinsic dimensions', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new IntrinsicWidth(
+        child: new IntrinsicHeight(
+          child: new TimePicker(
+            onChanged: null,
+            selectedTime: new TimeOfDay(hour: 0, minute: 0)
+          )
+        )
+      )
+    );
+    await tester.pump(const Duration(seconds: 5));
+  });
+
   testWidgets('drag-select an hour', (WidgetTester tester) async {
     Key _timePickerKey = new UniqueKey();
     TimeOfDay _selectedTime = const TimeOfDay(hour: 7, minute: 0);