packages/flutter/lib/src/material/button.dart - mirrors/flutter - Git at Google

 // 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 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';

 import 'button_theme.dart';
 import 'colors.dart';
 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.
 ///
 /// This class does not use the current [Theme] or [ButtonTheme] to
 /// compute default values for unspecified parameters. It's intended to
 /// be used for custom Material buttons that optionally incorporate defaults
 /// from the themes or from app-specific sources.
 ///
 /// [RaisedButton] and [FlatButton] configure a [RawMaterialButton] based
 /// on the current [Theme] and [ButtonTheme].
 class RawMaterialButton extends StatefulWidget {
   /// Create a button based on [Semantics], [Material], and [InkWell] widgets.
   ///
   /// The [shape], [elevation], [padding], [constraints], and [clipBehavior]
   /// arguments must not be null.
   const RawMaterialButton({
     Key key,
     @required this.onPressed,
     this.onHighlightChanged,
     this.textStyle,
     this.fillColor,
     this.highlightColor,
     this.splashColor,
     this.elevation = 2.0,
     this.highlightElevation = 8.0,
     this.disabledElevation = 0.0,
     this.padding = EdgeInsets.zero,
     this.constraints = const BoxConstraints(minWidth: 88.0, minHeight: 36.0),
     this.shape = const RoundedRectangleBorder(),
     this.animationDuration = kThemeChangeDuration,
     this.clipBehavior = Clip.none,
     MaterialTapTargetSize materialTapTargetSize,
     this.child,
   }) : this.materialTapTargetSize = materialTapTargetSize ?? MaterialTapTargetSize.padded,
        assert(shape != null),
        assert(elevation != null),
        assert(highlightElevation != null),
        assert(disabledElevation != null),
        assert(padding != null),
        assert(constraints != null),
        assert(animationDuration != null),
        assert(clipBehavior != null),
        super(key: key);

   /// Called when the button is tapped or otherwise activated.
   ///
   /// If this is set to null, the button will be disabled, see [enabled].
   final VoidCallback onPressed;

   /// Called by the underlying [InkWell] widget's [InkWell.onHighlightChanged]
   /// callback.
   final ValueChanged<bool> onHighlightChanged;

   /// Defines the default text style, with [Material.textStyle], for the
   /// button's [child].
   final TextStyle textStyle;

   /// The color of the button's [Material].
   final Color fillColor;

   /// The highlight color for the button's [InkWell].
   final Color highlightColor;

   /// The splash color for the button's [InkWell].
   final Color splashColor;

   /// The elevation for the button's [Material] when the button
   /// is [enabled] but not pressed.
   ///
   /// Defaults to 2.0.
   ///
   /// See also:
   ///
   ///  * [highlightElevation], the default elevation.
   ///  * [disabledElevation], the elevation when the button is disabled.
   final double elevation;

   /// The elevation for the button's [Material] when the button
   /// is [enabled] and pressed.
   ///
   /// Defaults to 8.0.
   ///
   /// See also:
   ///
   ///  * [elevation], the default elevation.
   ///  * [disabledElevation], the elevation when the button is disabled.
   final double highlightElevation;

   /// The elevation for the button's [Material] when the button
   /// is not [enabled].
   ///
   /// Defaults to 0.0.
   ///
   ///  * [elevation], the default elevation.
   ///  * [highlightElevation], the elevation when the button is pressed.
   final double disabledElevation;

   /// The internal padding for the button's [child].
   final EdgeInsetsGeometry padding;

   /// Defines the button's size.
   ///
   /// Typically used to constrain the button's minimum size.
   final BoxConstraints constraints;

   /// The shape of the button's [Material].
   ///
   /// The button's highlight and splash are clipped to this shape. If the
   /// button has an elevation, then its drop shadow is defined by this shape.
   final ShapeBorder shape;

   /// Defines the duration of animated changes for [shape] and [elevation].
   ///
   /// The default value is [kThemeChangeDuration].
   final Duration animationDuration;

   /// Typically the button's label.
   final Widget child;

   /// 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;

   /// 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;

   /// {@macro flutter.widgets.Clip}
   final Clip clipBehavior;

   @override
   _RawMaterialButtonState createState() => new _RawMaterialButtonState();
 }

 class _RawMaterialButtonState extends State<RawMaterialButton> {
   bool _highlight = false;
   void _handleHighlightChanged(bool value) {
     setState(() {
       _highlight = value;
       if (widget.onHighlightChanged != null)
         widget.onHighlightChanged(value);
     });
   }

   @override
   Widget build(BuildContext context) {
     final double elevation = widget.enabled
       ? (_highlight ? widget.highlightElevation : widget.elevation)
       : widget.disabledElevation;

     final Widget result = new ConstrainedBox(
       constraints: widget.constraints,
       child: new Material(
         elevation: elevation,
         textStyle: widget.textStyle,
         shape: widget.shape,
         color: widget.fillColor,
         type: widget.fillColor == null ? MaterialType.transparency : MaterialType.button,
         animationDuration: widget.animationDuration,
         clipBehavior: widget.clipBehavior,
         child: new InkWell(
           onHighlightChanged: _handleHighlightChanged,
           splashColor: widget.splashColor,
           highlightColor: widget.highlightColor,
           onTap: widget.onPressed,
           customBorder: widget.shape,
           child: IconTheme.merge(
             data: new IconThemeData(color: widget.textStyle?.color),
             child: new Container(
               padding: widget.padding,
               child: new Center(
                 widthFactor: 1.0,
                 heightFactor: 1.0,
                 child: widget.child,
               ),
             ),
           ),
         ),
       ),
     );
     Size minSize;
     switch (widget.materialTapTargetSize) {
       case MaterialTapTargetSize.padded:
         minSize = const Size(48.0, 48.0);
         break;
       case MaterialTapTargetSize.shrinkWrap:
         minSize = Size.zero;
         break;
     }

     return new Semantics(
       container: true,
       button: true,
       enabled: widget.enabled,
       child: new _InputPadding(
         minSize: minSize,
         child: result,
       ),
     );
   }
 }

 /// A utility class for building Material buttons that depend on the
 /// ambient [ButtonTheme] and [Theme].
 ///
 /// The button's size will expand to fit the child widget, if necessary.
 ///
 /// MaterialButtons whose [onPressed] handler is null will be disabled. To have
 /// an enabled button, make sure to pass a non-null value for onPressed.
 ///
 /// Rather than using this class directly, consider using [FlatButton] or
 /// [RaisedButton], which configure this class with appropriate defaults that
 /// match the material design specification.
 ///
 /// To create a button directly, without inheriting theme defaults, use
 /// [RawMaterialButton].
 ///
 /// If you want an ink-splash effect for taps, but don't want to use a button,
 /// consider using [InkWell] directly.
 ///
 /// See also:
 ///
 ///  * [IconButton], to create buttons that contain icons rather than text.
 class MaterialButton extends StatelessWidget {
   /// Creates a material button.
   ///
   /// Rather than creating a material button directly, consider using
   /// [FlatButton] or [RaisedButton]. To create a custom Material button
   /// consider using [RawMaterialButton].
   ///
   /// The [clipBehavior] argument must not be null.
   const MaterialButton({
     Key key,
     this.colorBrightness,
     this.textTheme,
     this.textColor,
     this.color,
     this.highlightColor,
     this.splashColor,
     this.elevation,
     this.highlightElevation,
     this.minWidth,
     this.height,
     this.padding,
     this.materialTapTargetSize,
     this.clipBehavior = Clip.none,
     @required this.onPressed,
     this.child
   }) : assert(clipBehavior != null), super(key: key);

   /// The theme brightness to use for this button.
   ///
   /// Defaults to the brightness from [ThemeData.brightness].
   final Brightness colorBrightness;

   /// Defines the button's base colors, and the defaults for the button's minimum
   /// size, internal padding, and shape.
   final ButtonTextTheme textTheme;

   /// The color to use for this button's text.
   final Color textColor;

   /// The button's fill color, displayed by its [Material], while the button
   /// is in its default (unpressed, enabled) state.
   ///
   /// Defaults to null, meaning that the color is automatically derived from the [Theme].
   ///
   /// Typically, a material design color will be used, as follows:
   ///
   /// ```dart
   ///  new MaterialButton(
   ///    color: Colors.blue[500],
   ///    onPressed: _handleTap,
   ///    child: new Text('DEMO'),
   ///  ),
   /// ```
   final Color color;

   /// The primary color of the button when the button is in the down (pressed)
   /// state.
   ///
   /// The splash is represented as a circular overlay that appears above the
   /// [highlightColor] overlay. The splash overlay has a center point that
   /// matches the hit point of the user touch event. The splash overlay will
   /// expand to fill the button area if the touch is held for long enough time.
   /// If the splash color has transparency then the highlight and button color
   /// will show through.
   ///
   /// Defaults to the Theme's splash color, [ThemeData.splashColor].
   final Color splashColor;

   /// The secondary color of the button when the button is in the down (pressed)
   /// state.
   ///
   /// The highlight color is represented as a solid color that is overlaid over
   /// the button color (if any). If the highlight color has transparency, the
   /// button color will show through. The highlight fades in quickly as the
   /// button is held down.
   ///
   /// Defaults to the Theme's highlight color, [ThemeData.highlightColor].
   final Color highlightColor;

   /// The z-coordinate at which to place this button. This controls the size of
   /// the shadow below the button.
   ///
   /// Defaults to 0.
   ///
   /// See also:
   ///
   ///  * [FlatButton], a material button specialized for the case where the
   ///    elevation is zero.
   ///  * [RaisedButton], a material button specialized for the case where the
   ///    elevation is non-zero.
   final double elevation;

   /// The z-coordinate at which to place this button when highlighted. This
   /// controls the size of the shadow below the button.
   ///
   /// Defaults to 0.
   ///
   /// See also:
   ///
   ///  * [elevation], the default elevation.
   final double highlightElevation;

   /// The smallest horizontal extent that the button will occupy.
   ///
   /// Defaults to the value from the current [ButtonTheme].
   final double minWidth;

   /// The vertical extent of the button.
   ///
   /// Defaults to the value from the current [ButtonTheme].
   final double height;

   /// The internal padding for the button's [child].
   ///
   /// Defaults to the value from the current [ButtonTheme],
   /// [ButtonThemeData.padding].
   final EdgeInsetsGeometry padding;

   /// The callback that is called when the button is tapped or otherwise activated.
   ///
   /// If this is set to null, the button will be disabled.
   final VoidCallback onPressed;

   /// The widget below this widget in the tree.
   ///
   /// {@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;

   /// {@macro flutter.widgets.Clip}
   final Clip clipBehavior;

   /// 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;

   Brightness _getBrightness(ThemeData theme) {
     return colorBrightness ?? theme.brightness;
   }

   ButtonTextTheme _getTextTheme(ButtonThemeData buttonTheme) {
     return textTheme ?? buttonTheme.textTheme;
   }

   Color _getTextColor(ThemeData theme, ButtonThemeData buttonTheme, Color fillColor) {
     if (textColor != null)
       return textColor;

     final bool themeIsDark = _getBrightness(theme) == Brightness.dark;
     final bool fillIsDark = fillColor != null
       ? ThemeData.estimateBrightnessForColor(fillColor) == Brightness.dark
       : themeIsDark;

     switch (_getTextTheme(buttonTheme)) {
       case ButtonTextTheme.normal:
         return enabled
           ? (themeIsDark ? Colors.white : Colors.black87)
           : (themeIsDark ? Colors.white30 : Colors.black26);
       case ButtonTextTheme.accent:
         return enabled
           ? theme.accentColor
           : (themeIsDark ? Colors.white30 : Colors.black26);
       case ButtonTextTheme.primary:
         return enabled
           ? (fillIsDark ? Colors.white : Colors.black)
           : (themeIsDark ? Colors.white30 : Colors.black38);
     }
     return null;
   }

   @override
   Widget build(BuildContext context) {
     final ThemeData theme = Theme.of(context);
     final ButtonThemeData buttonTheme = ButtonTheme.of(context);
     final Color textColor = _getTextColor(theme, buttonTheme, color);

     return new RawMaterialButton(
       onPressed: onPressed,
       fillColor: color,
       textStyle: theme.textTheme.button.copyWith(color: textColor),
       highlightColor: highlightColor ?? theme.highlightColor,
       splashColor: splashColor ?? theme.splashColor,
       elevation: elevation ?? 2.0,
       highlightElevation: highlightElevation ?? 8.0,
       padding: padding ?? buttonTheme.padding,
       constraints: buttonTheme.constraints.copyWith(
         minWidth: minWidth,
         minHeight: height,
       ),
       shape: buttonTheme.shape,
       child: child,
       materialTapTargetSize: materialTapTargetSize ?? theme.materialTapTargetSize,
       clipBehavior: clipBehavior,
     );
   }

   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);
     properties.add(new FlagProperty('enabled', value: enabled, ifFalse: 'disabled'));
   }
 }

 /// A widget to pad the area around a [MaterialButton]'s inner [Material].
 ///
 /// Redirect taps that occur in the padded area around the child to the center
 /// of the child. This increases the size of the button and the button's
 /// "tap target", but not its material or its ink splashes.
 class _InputPadding extends SingleChildRenderObjectWidget {
   const _InputPadding({
     Key key,
     Widget child,
     this.minSize,
   }) : super(key: key, child: child);

   final Size minSize;

   @override
   RenderObject createRenderObject(BuildContext context) {
     return new _RenderInputPadding(minSize);
   }

   @override
   void updateRenderObject(BuildContext context, covariant _RenderInputPadding renderObject) {
     renderObject.minSize = minSize;
   }
 }

 class _RenderInputPadding extends RenderShiftedBox {
   _RenderInputPadding(this._minSize, [RenderBox child]) : super(child) ;

   Size get minSize => _minSize;
   Size _minSize;
   set minSize(Size value) {
     if (_minSize == value)
       return;
     _minSize = value;
     markNeedsLayout();
   }

   @override
   double computeMinIntrinsicWidth(double height) {
     if (child != null)
       return math.max(child.getMinIntrinsicWidth(height), minSize.width);
     return 0.0;
   }

   @override
   double computeMinIntrinsicHeight(double width) {
     if (child != null)
       return math.max(child.getMinIntrinsicHeight(width), minSize.height);
     return 0.0;
   }

   @override
   double computeMaxIntrinsicWidth(double height) {
     if (child != null)
       return math.max(child.getMaxIntrinsicWidth(height), minSize.width);
     return 0.0;
   }

   @override
   double computeMaxIntrinsicHeight(double width) {
     if (child != null)
       return math.max(child.getMaxIntrinsicHeight(width), minSize.height);
     return 0.0;
   }

   @override
   void performLayout() {
     if (child != null) {
       child.layout(constraints, parentUsesSize: true);
       final double height = math.max(child.size.width, minSize.width);
       final double width = math.max(child.size.height, minSize.height);
       size = constraints.constrain(new Size(height, width));
       final BoxParentData childParentData = child.parentData;
       childParentData.offset = Alignment.center.alongOffset(size - child.size);
     } else {
       size = Size.zero;
     }
   }

   @override
   bool hitTest(HitTestResult result, {Offset position}) {
     return super.hitTest(result, position: position) ||
       child.hitTest(result, position: child.size.center(Offset.zero));
   }
 }
	// 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 'package:flutter/foundation.dart';
	import 'package:flutter/rendering.dart';
	import 'package:flutter/widgets.dart';

	import 'button_theme.dart';
	import 'colors.dart';
	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.
	///
	/// This class does not use the current [Theme] or [ButtonTheme] to
	/// compute default values for unspecified parameters. It's intended to
	/// be used for custom Material buttons that optionally incorporate defaults
	/// from the themes or from app-specific sources.
	///
	/// [RaisedButton] and [FlatButton] configure a [RawMaterialButton] based
	/// on the current [Theme] and [ButtonTheme].
	class RawMaterialButton extends StatefulWidget {
	/// Create a button based on [Semantics], [Material], and [InkWell] widgets.
	///
	/// The [shape], [elevation], [padding], [constraints], and [clipBehavior]
	/// arguments must not be null.
	const RawMaterialButton({
	Key key,
	@required this.onPressed,
	this.onHighlightChanged,
	this.textStyle,
	this.fillColor,
	this.highlightColor,
	this.splashColor,
	this.elevation = 2.0,
	this.highlightElevation = 8.0,
	this.disabledElevation = 0.0,
	this.padding = EdgeInsets.zero,
	this.constraints = const BoxConstraints(minWidth: 88.0, minHeight: 36.0),
	this.shape = const RoundedRectangleBorder(),
	this.animationDuration = kThemeChangeDuration,
	this.clipBehavior = Clip.none,
	MaterialTapTargetSize materialTapTargetSize,
	this.child,
	}) : this.materialTapTargetSize = materialTapTargetSize ?? MaterialTapTargetSize.padded,
	assert(shape != null),
	assert(elevation != null),
	assert(highlightElevation != null),
	assert(disabledElevation != null),
	assert(padding != null),
	assert(constraints != null),
	assert(animationDuration != null),
	assert(clipBehavior != null),
	super(key: key);

	/// Called when the button is tapped or otherwise activated.
	///
	/// If this is set to null, the button will be disabled, see [enabled].
	final VoidCallback onPressed;

	/// Called by the underlying [InkWell] widget's [InkWell.onHighlightChanged]
	/// callback.
	final ValueChanged<bool> onHighlightChanged;

	/// Defines the default text style, with [Material.textStyle], for the
	/// button's [child].
	final TextStyle textStyle;

	/// The color of the button's [Material].
	final Color fillColor;

	/// The highlight color for the button's [InkWell].
	final Color highlightColor;

	/// The splash color for the button's [InkWell].
	final Color splashColor;

	/// The elevation for the button's [Material] when the button
	/// is [enabled] but not pressed.
	///
	/// Defaults to 2.0.
	///
	/// See also:
	///
	/// * [highlightElevation], the default elevation.
	/// * [disabledElevation], the elevation when the button is disabled.
	final double elevation;

	/// The elevation for the button's [Material] when the button
	/// is [enabled] and pressed.
	///
	/// Defaults to 8.0.
	///
	/// See also:
	///
	/// * [elevation], the default elevation.
	/// * [disabledElevation], the elevation when the button is disabled.
	final double highlightElevation;

	/// The elevation for the button's [Material] when the button
	/// is not [enabled].
	///
	/// Defaults to 0.0.
	///
	/// * [elevation], the default elevation.
	/// * [highlightElevation], the elevation when the button is pressed.
	final double disabledElevation;

	/// The internal padding for the button's [child].
	final EdgeInsetsGeometry padding;

	/// Defines the button's size.
	///
	/// Typically used to constrain the button's minimum size.
	final BoxConstraints constraints;

	/// The shape of the button's [Material].
	///
	/// The button's highlight and splash are clipped to this shape. If the
	/// button has an elevation, then its drop shadow is defined by this shape.
	final ShapeBorder shape;

	/// Defines the duration of animated changes for [shape] and [elevation].
	///
	/// The default value is [kThemeChangeDuration].
	final Duration animationDuration;

	/// Typically the button's label.
	final Widget child;

	/// 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;

	/// 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;

	/// {@macro flutter.widgets.Clip}
	final Clip clipBehavior;

	@override
	_RawMaterialButtonState createState() => new _RawMaterialButtonState();
	}

	class _RawMaterialButtonState extends State<RawMaterialButton> {
	bool _highlight = false;
	void _handleHighlightChanged(bool value) {
	setState(() {
	_highlight = value;
	if (widget.onHighlightChanged != null)
	widget.onHighlightChanged(value);
	});
	}

	@override
	Widget build(BuildContext context) {
	final double elevation = widget.enabled
	? (_highlight ? widget.highlightElevation : widget.elevation)
	: widget.disabledElevation;

	final Widget result = new ConstrainedBox(
	constraints: widget.constraints,
	child: new Material(
	elevation: elevation,
	textStyle: widget.textStyle,
	shape: widget.shape,
	color: widget.fillColor,
	type: widget.fillColor == null ? MaterialType.transparency : MaterialType.button,
	animationDuration: widget.animationDuration,
	clipBehavior: widget.clipBehavior,
	child: new InkWell(
	onHighlightChanged: _handleHighlightChanged,
	splashColor: widget.splashColor,
	highlightColor: widget.highlightColor,
	onTap: widget.onPressed,
	customBorder: widget.shape,
	child: IconTheme.merge(
	data: new IconThemeData(color: widget.textStyle?.color),
	child: new Container(
	padding: widget.padding,
	child: new Center(
	widthFactor: 1.0,
	heightFactor: 1.0,
	child: widget.child,
	),
	),
	),
	),
	),
	);
	Size minSize;
	switch (widget.materialTapTargetSize) {
	case MaterialTapTargetSize.padded:
	minSize = const Size(48.0, 48.0);
	break;
	case MaterialTapTargetSize.shrinkWrap:
	minSize = Size.zero;
	break;
	}

	return new Semantics(
	container: true,
	button: true,
	enabled: widget.enabled,
	child: new _InputPadding(
	minSize: minSize,
	child: result,
	),
	);
	}
	}

	/// A utility class for building Material buttons that depend on the
	/// ambient [ButtonTheme] and [Theme].
	///
	/// The button's size will expand to fit the child widget, if necessary.
	///
	/// MaterialButtons whose [onPressed] handler is null will be disabled. To have
	/// an enabled button, make sure to pass a non-null value for onPressed.
	///
	/// Rather than using this class directly, consider using [FlatButton] or
	/// [RaisedButton], which configure this class with appropriate defaults that
	/// match the material design specification.
	///
	/// To create a button directly, without inheriting theme defaults, use
	/// [RawMaterialButton].
	///
	/// If you want an ink-splash effect for taps, but don't want to use a button,
	/// consider using [InkWell] directly.
	///
	/// See also:
	///
	/// * [IconButton], to create buttons that contain icons rather than text.
	class MaterialButton extends StatelessWidget {
	/// Creates a material button.
	///
	/// Rather than creating a material button directly, consider using
	/// [FlatButton] or [RaisedButton]. To create a custom Material button
	/// consider using [RawMaterialButton].
	///
	/// The [clipBehavior] argument must not be null.
	const MaterialButton({
	Key key,
	this.colorBrightness,
	this.textTheme,
	this.textColor,
	this.color,
	this.highlightColor,
	this.splashColor,
	this.elevation,
	this.highlightElevation,
	this.minWidth,
	this.height,
	this.padding,
	this.materialTapTargetSize,
	this.clipBehavior = Clip.none,
	@required this.onPressed,
	this.child
	}) : assert(clipBehavior != null), super(key: key);

	/// The theme brightness to use for this button.
	///
	/// Defaults to the brightness from [ThemeData.brightness].
	final Brightness colorBrightness;

	/// Defines the button's base colors, and the defaults for the button's minimum
	/// size, internal padding, and shape.
	final ButtonTextTheme textTheme;

	/// The color to use for this button's text.
	final Color textColor;

	/// The button's fill color, displayed by its [Material], while the button
	/// is in its default (unpressed, enabled) state.
	///
	/// Defaults to null, meaning that the color is automatically derived from the [Theme].
	///
	/// Typically, a material design color will be used, as follows:
	///
	/// ```dart
	/// new MaterialButton(
	/// color: Colors.blue[500],
	/// onPressed: _handleTap,
	/// child: new Text('DEMO'),
	/// ),
	/// ```
	final Color color;

	/// The primary color of the button when the button is in the down (pressed)
	/// state.
	///
	/// The splash is represented as a circular overlay that appears above the
	/// [highlightColor] overlay. The splash overlay has a center point that
	/// matches the hit point of the user touch event. The splash overlay will
	/// expand to fill the button area if the touch is held for long enough time.
	/// If the splash color has transparency then the highlight and button color
	/// will show through.
	///
	/// Defaults to the Theme's splash color, [ThemeData.splashColor].
	final Color splashColor;

	/// The secondary color of the button when the button is in the down (pressed)
	/// state.
	///
	/// The highlight color is represented as a solid color that is overlaid over
	/// the button color (if any). If the highlight color has transparency, the
	/// button color will show through. The highlight fades in quickly as the
	/// button is held down.
	///
	/// Defaults to the Theme's highlight color, [ThemeData.highlightColor].
	final Color highlightColor;

	/// The z-coordinate at which to place this button. This controls the size of
	/// the shadow below the button.
	///
	/// Defaults to 0.
	///
	/// See also:
	///
	/// * [FlatButton], a material button specialized for the case where the
	/// elevation is zero.
	/// * [RaisedButton], a material button specialized for the case where the
	/// elevation is non-zero.
	final double elevation;

	/// The z-coordinate at which to place this button when highlighted. This
	/// controls the size of the shadow below the button.
	///
	/// Defaults to 0.
	///
	/// See also:
	///
	/// * [elevation], the default elevation.
	final double highlightElevation;

	/// The smallest horizontal extent that the button will occupy.
	///
	/// Defaults to the value from the current [ButtonTheme].
	final double minWidth;

	/// The vertical extent of the button.
	///
	/// Defaults to the value from the current [ButtonTheme].
	final double height;

	/// The internal padding for the button's [child].
	///
	/// Defaults to the value from the current [ButtonTheme],
	/// [ButtonThemeData.padding].
	final EdgeInsetsGeometry padding;

	/// The callback that is called when the button is tapped or otherwise activated.
	///
	/// If this is set to null, the button will be disabled.
	final VoidCallback onPressed;

	/// The widget below this widget in the tree.
	///
	/// {@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;

	/// {@macro flutter.widgets.Clip}
	final Clip clipBehavior;

	/// 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;

	Brightness _getBrightness(ThemeData theme) {
	return colorBrightness ?? theme.brightness;
	}

	ButtonTextTheme _getTextTheme(ButtonThemeData buttonTheme) {
	return textTheme ?? buttonTheme.textTheme;
	}

	Color _getTextColor(ThemeData theme, ButtonThemeData buttonTheme, Color fillColor) {
	if (textColor != null)
	return textColor;

	final bool themeIsDark = _getBrightness(theme) == Brightness.dark;
	final bool fillIsDark = fillColor != null
	? ThemeData.estimateBrightnessForColor(fillColor) == Brightness.dark
	: themeIsDark;

	switch (_getTextTheme(buttonTheme)) {
	case ButtonTextTheme.normal:
	return enabled
	? (themeIsDark ? Colors.white : Colors.black87)
	: (themeIsDark ? Colors.white30 : Colors.black26);
	case ButtonTextTheme.accent:
	return enabled
	? theme.accentColor
	: (themeIsDark ? Colors.white30 : Colors.black26);
	case ButtonTextTheme.primary:
	return enabled
	? (fillIsDark ? Colors.white : Colors.black)
	: (themeIsDark ? Colors.white30 : Colors.black38);
	}
	return null;
	}

	@override
	Widget build(BuildContext context) {
	final ThemeData theme = Theme.of(context);
	final ButtonThemeData buttonTheme = ButtonTheme.of(context);
	final Color textColor = _getTextColor(theme, buttonTheme, color);

	return new RawMaterialButton(
	onPressed: onPressed,
	fillColor: color,
	textStyle: theme.textTheme.button.copyWith(color: textColor),
	highlightColor: highlightColor ?? theme.highlightColor,
	splashColor: splashColor ?? theme.splashColor,
	elevation: elevation ?? 2.0,
	highlightElevation: highlightElevation ?? 8.0,
	padding: padding ?? buttonTheme.padding,
	constraints: buttonTheme.constraints.copyWith(
	minWidth: minWidth,
	minHeight: height,
	),
	shape: buttonTheme.shape,
	child: child,
	materialTapTargetSize: materialTapTargetSize ?? theme.materialTapTargetSize,
	clipBehavior: clipBehavior,
	);
	}

	@override
	void debugFillProperties(DiagnosticPropertiesBuilder properties) {
	super.debugFillProperties(properties);
	properties.add(new FlagProperty('enabled', value: enabled, ifFalse: 'disabled'));
	}
	}

	/// A widget to pad the area around a [MaterialButton]'s inner [Material].
	///
	/// Redirect taps that occur in the padded area around the child to the center
	/// of the child. This increases the size of the button and the button's
	/// "tap target", but not its material or its ink splashes.
	class _InputPadding extends SingleChildRenderObjectWidget {
	const _InputPadding({
	Key key,
	Widget child,
	this.minSize,
	}) : super(key: key, child: child);

	final Size minSize;

	@override
	RenderObject createRenderObject(BuildContext context) {
	return new _RenderInputPadding(minSize);
	}

	@override
	void updateRenderObject(BuildContext context, covariant _RenderInputPadding renderObject) {
	renderObject.minSize = minSize;
	}
	}

	class _RenderInputPadding extends RenderShiftedBox {
	_RenderInputPadding(this._minSize, [RenderBox child]) : super(child) ;

	Size get minSize => _minSize;
	Size _minSize;
	set minSize(Size value) {
	if (_minSize == value)
	return;
	_minSize = value;
	markNeedsLayout();
	}

	@override
	double computeMinIntrinsicWidth(double height) {
	if (child != null)
	return math.max(child.getMinIntrinsicWidth(height), minSize.width);
	return 0.0;
	}

	@override
	double computeMinIntrinsicHeight(double width) {
	if (child != null)
	return math.max(child.getMinIntrinsicHeight(width), minSize.height);
	return 0.0;
	}

	@override
	double computeMaxIntrinsicWidth(double height) {
	if (child != null)
	return math.max(child.getMaxIntrinsicWidth(height), minSize.width);
	return 0.0;
	}

	@override
	double computeMaxIntrinsicHeight(double width) {
	if (child != null)
	return math.max(child.getMaxIntrinsicHeight(width), minSize.height);
	return 0.0;
	}

	@override
	void performLayout() {
	if (child != null) {
	child.layout(constraints, parentUsesSize: true);
	final double height = math.max(child.size.width, minSize.width);
	final double width = math.max(child.size.height, minSize.height);
	size = constraints.constrain(new Size(height, width));
	final BoxParentData childParentData = child.parentData;
	childParentData.offset = Alignment.center.alongOffset(size - child.size);
	} else {
	size = Size.zero;
	}
	}

	@override
	bool hitTest(HitTestResult result, {Offset position}) {
	return super.hitTest(result, position: position) \|\|
	child.hitTest(result, position: child.size.center(Offset.zero));
	}
	}