Add date picker to widgets library and teach fitness app to use it

Also, add an example for the date picker

examples/fitness/lib/date_utils.dart

@@ -13,6 +13,12 @@ class DateUtils {
   static const MS_IN_WEEK =
         DateTime.DAYS_PER_WEEK * Duration.MILLISECONDS_PER_DAY;
 
+  // TODO(jmesserly): locale specific date format
+  static String _twoDigits(int n) {
+    if (n >= 10) return "${n}";
+    return "0${n}";
+  }
+
   /** Formats a time in H:MM A format */
   static String toHourMinutesString(Duration duration) {
     assert(duration.inDays == 0);
@@ -68,14 +74,16 @@ class DateUtils {
     } else if (delta.inMilliseconds < MS_IN_WEEK) {
       return WEEKDAYS[then.weekday];
     } else {
-      // TODO(jmesserly): locale specific date format
-      String twoDigits(int n) {
-        if (n >= 10) return "${n}";
-        return "0${n}";
-      }
-      String twoDigitMonth = twoDigits(then.month);
-      String twoDigitDay = twoDigits(then.day);
+      String twoDigitMonth = _twoDigits(then.month);
+      String twoDigitDay = _twoDigits(then.day);
       return "${then.year}-${twoDigitMonth}-${twoDigitDay}";
     }
   }
+
+  static String toDateString(DateTime then) {
+    // TODO(jmesserly): locale specific date format
+    String twoDigitMonth = _twoDigits(then.month);
+    String twoDigitDay = _twoDigits(then.day);
+    return "${then.year}-${twoDigitMonth}-${twoDigitDay}";
+  }
 }

examples/fitness/lib/fitness_item.dart

@@ -21,7 +21,7 @@ abstract class FitnessItem {
   Map toJson() => { 'when' : when.toIso8601String() };
 
   // TODO(jackson): Internationalize
-  String get displayDate => DateUtils.toRecentTimeString(when);
+  String get displayDate => DateUtils.toDateString(when);
 
   FitnessItemRow toRow({ FitnessItemHandler onDismissed });
 }

examples/fitness/lib/measurement.dart

@@ -17,6 +17,7 @@ class Measurement extends FitnessItem {
   Map toJson() {
     Map json = super.toJson();
     json['weight'] = weight;
+    json['type'] = runtimeType.toString();
     return json;
   }
 
@@ -53,6 +54,55 @@ class MeasurementRow extends FitnessItemRow {
   }
 }
 
+class MeasurementDateDialog extends StatefulComponent {
+  MeasurementDateDialog({ this.navigator, this.previousDate });
+
+  Navigator navigator;
+  DateTime previousDate;
+
+  @override
+  void initState() {
+    _selectedDate = previousDate;
+  }
+
+  void syncConstructorArguments(MeasurementDateDialog source) {
+    navigator = source.navigator;
+    previousDate = source.previousDate;
+  }
+
+  DateTime _selectedDate;
+
+  void _handleDateChanged(DateTime value) {
+    setState(() {
+      _selectedDate = value;
+    });
+  }
+
+  Widget build() {
+    return new Dialog(
+      content: new DatePicker(
+        selectedDate: _selectedDate,
+        firstDate: new DateTime(2015, 8),
+        lastDate: new DateTime(2101),
+        onChanged: _handleDateChanged
+      ),
+      contentPadding: EdgeDims.zero,
+      actions: [
+        new FlatButton(
+          child: new Text('CANCEL'),
+          onPressed: navigator.pop
+        ),
+        new FlatButton(
+          child: new Text('OK'),
+          onPressed: () {
+            navigator.pop(_selectedDate);
+          }
+        ),
+      ]
+    );
+  }
+}
+
 class MeasurementFragment extends StatefulComponent {
 
   MeasurementFragment({ this.navigator, this.onCreated });
@@ -66,6 +116,7 @@ class MeasurementFragment extends StatefulComponent {
   }
 
   String _weight = "";
+  DateTime _when = new DateTime.now();
   String _errorMessage = null;
 
   EventDisposition _handleSave() {
@@ -79,7 +130,7 @@ class MeasurementFragment extends StatefulComponent {
       });
       return EventDisposition.processed;
     }
-    onCreated(new Measurement(when: new DateTime.now(), weight: parsedWeight));
+    onCreated(new Measurement(when: _when, weight: parsedWeight));
     navigator.pop();
     return EventDisposition.processed;
   }
@@ -107,23 +158,44 @@ class MeasurementFragment extends StatefulComponent {
 
   static final GlobalKey weightKey = new GlobalKey();
 
+  EventDisposition _handleDatePressed(_) {
+    showDialog(navigator, (navigator) {
+      return new MeasurementDateDialog(navigator: navigator, previousDate: _when);
+    }).then((DateTime value) {
+      if (value == null)
+        return;
+      setState(() {
+        _when = value;
+      });
+    });
+    return EventDisposition.processed;
+  }
+
   Widget buildBody() {
-    Measurement measurement = new Measurement(when: new DateTime.now());
+    Measurement measurement = new Measurement(when: _when);
+    // TODO(jackson): Revisit the layout of this pane to be more maintainable
     return new Material(
       type: MaterialType.canvas,
-      child: new ScrollableViewport(
-        child: new Container(
-          padding: const EdgeDims.all(20.0),
-          child: new BlockBody([
-            new Text(measurement.displayDate),
-            new Input(
-              key: weightKey,
-              placeholder: 'Enter weight',
-              keyboardType: KeyboardType_NUMBER,
-              onChanged: _handleWeightChanged
-            ),
-          ])
-        )
+      child: new Container(
+        padding: const EdgeDims.all(20.0),
+        child: new Column([
+          new Listener(
+            onGestureTap: _handleDatePressed,
+            child: new Container(
+              height: 50.0,
+              child: new Column([
+                new Text('Measurement Date'),
+                new Text(measurement.displayDate, style: Theme.of(this).text.caption),
+              ], alignItems: FlexAlignItems.start)
+            )
+          ),
+          new Input(
+            key: weightKey,
+            placeholder: 'Enter weight',
+            keyboardType: KeyboardType_NUMBER,
+            onChanged: _handleWeightChanged
+          ),
+        ], alignItems: FlexAlignItems.stretch)
       )
     );
   }

examples/widgets/date_picker.dart

@@ -0,0 +1,62 @@
+// 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:sky/widgets.dart';
+import 'package:sky/theme/colors.dart' as colors;
+
+void main() => runApp(new DatePickerDemo());
+
+class DatePickerDemo extends App {
+
+  DateTime _dateTime;
+
+  void initState() {
+    DateTime now = new DateTime.now();
+    _dateTime = new DateTime(now.year, now.month, now.day);
+  }
+
+  void _handleDateChanged(DateTime dateTime) {
+    setState(() {
+      _dateTime = dateTime;
+    });
+  }
+
+  Widget build() {
+    return new Theme(
+      data: new ThemeData(
+        brightness: ThemeBrightness.light,
+        primarySwatch: colors.Teal
+      ),
+      child: new Stack([
+        new Scaffold(
+          toolbar: new ToolBar(center: new Text("Date Picker")),
+          body: new Material(
+            child: new Row(
+              [new Text(_dateTime.toString())],
+              alignItems: FlexAlignItems.end,
+              justifyContent: FlexJustifyContent.center
+            )
+          )
+        ),
+        new Dialog(
+          content: new DatePicker(
+            selectedDate: _dateTime,
+            firstDate: new DateTime(2015, 8),
+            lastDate: new DateTime(2101),
+            onChanged: _handleDateChanged
+          ),
+          contentPadding: EdgeDims.zero,
+          actions: [
+            new FlatButton(
+              child: new Text('CANCEL')
+            ),
+            new FlatButton(
+              child: new Text('OK')
+            ),
+          ]
+        )
+      ])
+    );
+  }
+}

sky/packages/sky/lib/widgets.dart

@@ -10,6 +10,7 @@ export 'widgets/basic.dart';
 export 'widgets/button_base.dart';
 export 'widgets/card.dart';
 export 'widgets/checkbox.dart';
+export 'widgets/date_picker.dart';
 export 'widgets/default_text_style.dart';
 export 'widgets/dialog.dart';
 export 'widgets/dismissable.dart';

sky/packages/sky/lib/widgets/date_picker.dart

@@ -0,0 +1,393 @@
+// 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:async';
+
+import 'package:sky/theme/colors.dart' as colors;
+import 'package:sky/theme/typography.dart' as typography;
+import 'package:sky/widgets.dart';
+import 'package:intl/intl.dart';
+import 'package:intl/date_symbols.dart';
+
+typedef void DatePickerValueChanged(DateTime dateTime);
+
+enum DatePickerMode { day, year }
+
+typedef void DatePickerModeChanged(DatePickerMode value);
+
+class DatePicker extends StatefulComponent {
+  DatePicker({
+    this.selectedDate,
+    this.onChanged,
+    this.firstDate,
+    this.lastDate
+  }) {
+    assert(selectedDate != null);
+    assert(firstDate != null);
+    assert(lastDate != null);
+  }
+
+  DateTime selectedDate;
+  DatePickerValueChanged onChanged;
+  DateTime firstDate;
+  DateTime lastDate;
+
+  void syncConstructorArguments(DatePicker source) {
+    selectedDate = source.selectedDate;
+    onChanged = source.onChanged;
+    firstDate = source.firstDate;
+    lastDate = source.lastDate;
+  }
+
+  DatePickerMode _mode = DatePickerMode.day;
+
+  void _handleModeChanged(DatePickerMode mode) {
+    setState(() {
+      _mode = mode;
+    });
+  }
+
+  void _handleYearChanged(DateTime dateTime) {
+    setState(() {
+      _mode = DatePickerMode.day;
+    });
+    if (onChanged != null)
+      onChanged(dateTime);
+  }
+
+  static const double _calendarHeight = 210.0;
+
+  Widget build() {
+    Widget header = new DatePickerHeader(
+      selectedDate: selectedDate,
+      mode: _mode,
+      onModeChanged: _handleModeChanged
+    );
+    Widget picker;
+    switch (_mode) {
+      case DatePickerMode.day:
+        picker = new MonthPicker(
+          selectedDate: selectedDate,
+          onChanged: onChanged,
+          firstDate: firstDate,
+          lastDate: lastDate,
+          itemExtent: _calendarHeight
+        );
+        break;
+      case DatePickerMode.year:
+        picker = new YearPicker(
+          selectedDate: selectedDate,
+          onChanged: _handleYearChanged,
+          firstDate: firstDate,
+          lastDate: lastDate
+        );
+        break;
+    }
+    return new BlockBody([header, new Container(height: _calendarHeight, child: picker)]);
+  }
+
+}
+
+// Shows the selected date in large font and toggles between year and day mode
+class DatePickerHeader extends Component {
+  DatePickerHeader({ this.selectedDate, this.mode, this.onModeChanged }) {
+    assert(selectedDate != null);
+    assert(mode != null);
+  }
+
+  DateTime selectedDate;
+  DatePickerMode mode;
+  DatePickerModeChanged onModeChanged;
+
+  EventDisposition _handleChangeMode(DatePickerMode value) {
+    if (value == mode)
+      return EventDisposition.ignored;
+    onModeChanged(value);
+    return EventDisposition.processed;
+  }
+
+  Widget build() {
+    ThemeData theme = Theme.of(this);
+    typography.TextTheme headerTheme;
+    Color dayColor;
+    Color yearColor;
+    switch(theme.primaryColorBrightness) {
+      case ThemeBrightness.light:
+        headerTheme = typography.black;
+        dayColor = mode == DatePickerMode.day ? colors.black87 : colors.black54;
+        yearColor = mode == DatePickerMode.year ? colors.black87 : colors.black54;
+        break;
+      case ThemeBrightness.dark:
+        headerTheme = typography.white;
+        dayColor = mode == DatePickerMode.day ? colors.white87 : colors.white54;
+        yearColor = mode == DatePickerMode.year ? colors.white87 : colors.white54;
+        break;
+    }
+    TextStyle dayStyle = headerTheme.display3.copyWith(color: dayColor, height: 1.0, fontSize: 100.0);
+    TextStyle monthStyle = headerTheme.headline.copyWith(color: dayColor, height: 1.0);
+    TextStyle yearStyle = headerTheme.headline.copyWith(color: yearColor, height: 1.0);
+    DateTime firstDate = new DateTime(1900);
+    DateTime lastDate = new DateTime(2101);
+
+    return new Container(
+      child: new BlockBody([
+        new Center(
+          child: new Listener(
+            child: new Text(new DateFormat("MMM").format(selectedDate).toUpperCase(), style: monthStyle),
+            onGestureTap: (_) => _handleChangeMode(DatePickerMode.day)
+          )
+        ),
+        new Center(
+          child: new Listener(
+            child: new Text(new DateFormat("d").format(selectedDate), style: dayStyle),
+            onGestureTap: (_) => _handleChangeMode(DatePickerMode.day)
+          )
+        ),
+        new Center(
+          child: new Listener(
+            child: new Text(new DateFormat("yyyy").format(selectedDate), style: yearStyle),
+            onGestureTap: (_) => _handleChangeMode(DatePickerMode.year)
+          )
+        )
+      ]),
+      padding: new EdgeDims.all(10.0),
+      decoration: new BoxDecoration(backgroundColor: theme.primaryColor)
+    );
+  }
+}
+
+// Fixed height component shows a single month and allows choosing a day
+class DayPicker extends Component {
+  DayPicker({
+    this.selectedDate,
+    this.currentDate,
+    this.onChanged,
+    this.displayedMonth
+  }) {
+    assert(selectedDate != null);
+    assert(currentDate != null);
+    assert(displayedMonth != null);
+  }
+
+  final DateTime selectedDate;
+  final DateTime currentDate;
+  final DatePickerValueChanged onChanged;
+  final DateTime displayedMonth;
+
+  Widget build() {
+    ThemeData theme = Theme.of(this);
+    TextStyle headerStyle = theme.text.caption.copyWith(fontWeight: FontWeight.w700);
+    TextStyle monthStyle = headerStyle.copyWith(fontSize: 14.0, height: 24.0 / 14.0);
+    TextStyle dayStyle = headerStyle.copyWith(fontWeight: FontWeight.w500);
+    DateFormat dateFormat = new DateFormat();
+    DateSymbols symbols = dateFormat.dateSymbols;
+
+    List<Text> headers = [];
+    for (String weekDay in symbols.NARROWWEEKDAYS) {
+      headers.add(new Text(weekDay, style: headerStyle));
+    }
+    List<Widget> rows = [
+      new Text(new DateFormat("MMMM y").format(displayedMonth), style: monthStyle),
+      new Flex(
+        headers,
+        justifyContent: FlexJustifyContent.spaceAround
+      )
+    ];
+    int year = displayedMonth.year;
+    int month = displayedMonth.month;
+    // Dart's Date time constructor is very forgiving and will understand
+    // month 13 as January of the next year. :)
+    int daysInMonth = new DateTime(year, month + 1).difference(new DateTime(year, month)).inDays;
+    int firstDay =  new DateTime(year, month).day;
+    int weeksShown = 6;
+    List<int> days = [
+      DateTime.SUNDAY,
+      DateTime.MONDAY,
+      DateTime.TUESDAY,
+      DateTime.WEDNESDAY,
+      DateTime.THURSDAY,
+      DateTime.FRIDAY,
+      DateTime.SATURDAY
+    ];
+    int daySlots = weeksShown * days.length;
+    List<Widget> labels = [];
+    for (int i = 0; i < daySlots; i++) {
+      // This assumes a start day of SUNDAY, but could be changed.
+      int day = i - firstDay + 1;
+      Widget item;
+      if (day < 1 || day > daysInMonth) {
+        item = new Text("");
+      } else {
+        // Put a light circle around the selected day
+        BoxDecoration decoration = null;
+        if (selectedDate.year == year &&
+            selectedDate.month == month &&
+            selectedDate.day == day)
+          decoration = new BoxDecoration(
+            backgroundColor: theme.primarySwatch[100],
+            shape: Shape.circle
+          );
+
+        // Use a different font color for the current day
+        TextStyle itemStyle = dayStyle;
+        if (currentDate.year == year &&
+            currentDate.month == month &&
+            currentDate.day == day)
+          itemStyle = itemStyle.copyWith(color: theme.primaryColor);
+
+        item = new Listener(
+          onGestureTap: (_) {
+            DateTime result = new DateTime(year, month, day);
+            if (onChanged != null)
+              onChanged(result);
+          },
+          child: new Container(
+            height: 30.0,
+            decoration: decoration,
+            child: new Center(
+              child: new Text(day.toString(), style: itemStyle)
+            )
+          )
+        );
+      }
+      labels.add(new Flexible(child: item));
+    }
+    for (int w = 0; w < weeksShown; w++) {
+      int startIndex = w * days.length;
+      rows.add(new Container(
+        child: new Flex(
+          labels.sublist(startIndex, startIndex + days.length),
+          justifyContent: FlexJustifyContent.spaceAround
+        )
+      ));
+    }
+
+    return new Column(rows);
+  }
+}
+
+// Scrollable list of DayPickers to allow choosing a month
+class MonthPicker extends ScrollableWidgetList {
+  MonthPicker({
+    this.selectedDate,
+    this.onChanged,
+    this.firstDate,
+    this.lastDate,
+    double itemExtent
+  }) : super(itemExtent: itemExtent) {
+    assert(selectedDate != null);
+    assert(lastDate.isAfter(firstDate));
+  }
+
+  DateTime selectedDate;
+  DatePickerValueChanged onChanged;
+  DateTime firstDate;
+  DateTime lastDate;
+
+  void syncConstructorArguments(MonthPicker source) {
+    selectedDate = source.selectedDate;
+    onChanged = source.onChanged;
+    firstDate = source.firstDate;
+    lastDate = source.lastDate;
+    super.syncConstructorArguments(source);
+  }
+
+  void initState() {
+    _updateCurrentDate();
+    super.initState();
+  }
+
+  DateTime _currentDate;
+  void _updateCurrentDate() {
+    _currentDate = new DateTime.now();
+    DateTime tomorrow = new DateTime(_currentDate.year, _currentDate.month, _currentDate.day + 1);
+    Duration timeUntilTomorrow = tomorrow.difference(_currentDate);
+    timeUntilTomorrow += const Duration(seconds: 1);  // so we don't miss it by rounding
+    new Timer(timeUntilTomorrow, () {
+      setState(() {
+        _updateCurrentDate();
+      });
+    });
+  }
+
+  int get itemCount => (lastDate.year - firstDate.year) * 12 + lastDate.month - firstDate.month + 1;
+
+  List<Widget> buildItems(int start, int count) {
+    List<Widget> result = new List<Widget>();
+    DateTime startDate = new DateTime(firstDate.year + start ~/ 12, firstDate.month + start % 12);
+    for (int i = 0; i < count; ++i) {
+      DateTime displayedMonth = new DateTime(startDate.year + i ~/ 12, startDate.month + i % 12);
+      Widget item = new Container(
+        height: itemExtent,
+        key: new ObjectKey(displayedMonth),
+        child: new DayPicker(
+          selectedDate: selectedDate,
+          currentDate: _currentDate,
+          onChanged: onChanged,
+          displayedMonth: displayedMonth
+        )
+      );
+      result.add(item);
+    }
+    return result;
+  }
+}
+
+// Scrollable list of years to allow picking a year
+class YearPicker extends ScrollableWidgetList {
+  YearPicker({
+    this.selectedDate,
+    this.onChanged,
+    this.firstDate,
+    this.lastDate
+  }) : super(itemExtent: 50.0) {
+    assert(selectedDate != null);
+    assert(lastDate.isAfter(firstDate));
+  }
+  DateTime selectedDate;
+  DatePickerValueChanged onChanged;
+  DateTime firstDate;
+  DateTime lastDate;
+
+  void syncConstructorArguments(YearPicker source) {
+    selectedDate = source.selectedDate;
+    onChanged = source.onChanged;
+    firstDate = source.firstDate;
+    lastDate = source.lastDate;
+    super.syncConstructorArguments(source);
+  }
+
+  int get itemCount => lastDate.year - firstDate.year + 1;
+
+  List<Widget> buildItems(int start, int count) {
+    TextStyle style = Theme.of(this).text.body1.copyWith(color: colors.black54);
+    List<Widget> items = new List<Widget>();
+    for(int i = start; i < start + count; i++) {
+      int year = firstDate.year + i;
+      String label = year.toString();
+      Widget item = new Listener(
+        key: new Key(label),
+        onGestureTap: (_) {
+          DateTime result = new DateTime(year, selectedDate.month, selectedDate.day);
+          if (onChanged != null)
+            onChanged(result);
+        },
+        child: new InkWell(
+          child: new Container(
+            height: itemExtent,
+            decoration: year == selectedDate.year ? new BoxDecoration(
+              backgroundColor: Theme.of(this).primarySwatch[100],
+              shape: Shape.circle
+            ) : null,
+            child: new Center(
+              child: new Text(label, style: style)
+            )
+          )
+        )
+      );
+      items.add(item);
+    }
+    return items;
+  }
+}

sky/packages/sky/lib/widgets/dialog.dart

@@ -25,7 +25,9 @@ class Dialog extends Component {
   Dialog({
     Key key,
     this.title,
+    this.titlePadding,
     this.content,
+    this.contentPadding,
     this.actions,
     this.onDismiss
   }): super(key: key);
@@ -34,10 +36,17 @@ class Dialog extends Component {
   /// of the dialog.
   final Widget title;
 
+  // Padding around the title; uses material design default if none is supplied
+  // If there is no title, no padding will be provided
+  final EdgeDims titlePadding;
+
   /// The (optional) content of the dialog is displayed in the center of the
   /// dialog in a lighter font.
   final Widget content;
 
+  // Padding around the content; uses material design default if none is supplied
+  final EdgeDims contentPadding;
+
   /// The (optional) set of actions that are displayed at the bottom of the
   /// dialog.
   final List<Widget> actions;
@@ -59,8 +68,11 @@ class Dialog extends Component {
     List<Widget> dialogBody = new List<Widget>();
 
     if (title != null) {
+      EdgeDims padding = titlePadding;
+      if (padding == null)
+        padding = new EdgeDims(24.0, 24.0, content == null ? 20.0 : 0.0, 24.0);
       dialogBody.add(new Padding(
-        padding: new EdgeDims(24.0, 24.0, content == null ? 20.0 : 0.0, 24.0),
+        padding: padding,
         child: new DefaultTextStyle(
           style: Theme.of(this).text.title,
           child: title
@@ -69,8 +81,11 @@ class Dialog extends Component {
     }
 
     if (content != null) {
+      EdgeDims padding = contentPadding;
+      if (padding == null)
+        padding = const EdgeDims(20.0, 24.0, 24.0, 24.0);
       dialogBody.add(new Padding(
-        padding: const EdgeDims(20.0, 24.0, 24.0, 24.0),
+        padding: padding,
         child: new DefaultTextStyle(
           style: Theme.of(this).text.subhead,
           child: content

sky/packages/sky/pubspec.yaml

@@ -13,5 +13,6 @@ dependencies:
   sky_services: ^0.0.14
   sky_tools: ^0.0.10
   vector_math: ^1.4.3
+  intl: ^0.12.4+2
 environment:
   sdk: '>=1.8.0 <2.0.0'