| // 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/widgets.dart'; |
| |
| import 'debug.dart'; |
| import 'icons.dart'; |
| import 'ink_well.dart'; |
| import 'material.dart'; |
| import 'theme.dart'; |
| import 'tooltip.dart'; |
| |
| // Minimum logical pixel size of the IconButton. |
| // See: <https://material.io/guidelines/layout/metrics-keylines.html#metrics-keylines-touch-target-size> |
| const double _kMinButtonSize = 48.0; |
| |
| /// A material design icon button. |
| /// |
| /// An icon button is a picture printed on a [Material] widget that reacts to |
| /// touches by filling with color (ink). |
| /// |
| /// Icon buttons are commonly used in the [AppBar.actions] field, but they can |
| /// be used in many other places as well. |
| /// |
| /// If the [onPressed] callback is null, then the button will be disabled and |
| /// will not react to touch. |
| /// |
| /// Requires one of its ancestors to be a [Material] widget. |
| /// |
| /// The hit region of an icon button will, if possible, be at least 48.0 pixels |
| /// in size, regardless of the actual [iconSize], to satisfy the [touch target |
| /// size](https://material.io/guidelines/layout/metrics-keylines.html#metrics-keylines-touch-target-size) |
| /// requirements in the Material Design specification. The [alignment] controls |
| /// how the icon itself is positioned within the hit region. |
| /// |
| /// ## Sample code |
| /// |
| /// ```dart |
| /// new IconButton( |
| /// icon: new Icon(Icons.volume_up), |
| /// tooltip: 'Increase volume by 10%', |
| /// onPressed: () { setState(() { _volume *= 1.1; }); }, |
| /// ) |
| /// ``` |
| /// |
| /// See also: |
| /// |
| /// * [Icons], a library of predefined icons. |
| /// * [BackButton], an icon button for a "back" affordance which adapts to the |
| /// current platform's conventions. |
| /// * [CloseButton], an icon button for closing pages. |
| /// * [AppBar], to show a toolbar at the top of an application. |
| /// * [RaisedButton] and [FlatButton], for buttons with text in them. |
| /// * [InkResponse] and [InkWell], for the ink splash effect itself. |
| class IconButton extends StatelessWidget { |
| /// Creates an icon button. |
| /// |
| /// Icon buttons are commonly used in the [AppBar.actions] field, but they can |
| /// be used in many other places as well. |
| /// |
| /// Requires one of its ancestors to be a [Material] widget. |
| /// |
| /// The [iconSize], [padding], and [alignment] arguments must not be null (though |
| /// they each have default values). |
| /// |
| /// The [icon] argument must be specified, and is typically either an [Icon] |
| /// or an [ImageIcon]. |
| const IconButton({ |
| Key key, |
| this.iconSize = 24.0, |
| this.padding = const EdgeInsets.all(8.0), |
| this.alignment = Alignment.center, |
| @required this.icon, |
| this.color, |
| this.highlightColor, |
| this.splashColor, |
| this.disabledColor, |
| @required this.onPressed, |
| this.tooltip |
| }) : assert(iconSize != null), |
| assert(padding != null), |
| assert(alignment != null), |
| assert(icon != null), |
| super(key: key); |
| |
| /// The size of the icon inside the button. |
| /// |
| /// This property must not be null. It defaults to 24.0. |
| /// |
| /// The size given here is passed down to the widget in the [icon] property |
| /// via an [IconTheme]. Setting the size here instead of in, for example, the |
| /// [Icon.size] property allows the [IconButton] to size the splash area to |
| /// fit the [Icon]. If you were to set the size of the [Icon] using |
| /// [Icon.size] instead, then the [IconButton] would default to 24.0 and then |
| /// the [Icon] itself would likely get clipped. |
| final double iconSize; |
| |
| /// The padding around the button's icon. The entire padded icon will react |
| /// to input gestures. |
| /// |
| /// This property must not be null. It defaults to 8.0 padding on all sides. |
| final EdgeInsetsGeometry padding; |
| |
| /// Defines how the icon is positioned within the IconButton. |
| /// |
| /// This property must not be null. It defaults to [Alignment.center]. |
| /// |
| /// See also: |
| /// |
| /// * [Alignment], a class with convenient constants typically used to |
| /// specify an [AlignmentGeometry]. |
| /// * [AlignmentDirectional], like [Alignment] for specifying alignments |
| /// relative to text direction. |
| final AlignmentGeometry alignment; |
| |
| /// The icon to display inside the button. |
| /// |
| /// The [Icon.size] and [Icon.color] of the icon is configured automatically |
| /// based on the [iconSize] and [color] properties of _this_ widget using an |
| /// [IconTheme] and therefore should not be explicitly given in the icon |
| /// widget. |
| /// |
| /// This property must not be null. |
| /// |
| /// See [Icon], [ImageIcon]. |
| final Widget icon; |
| |
| /// The color to use for the icon inside the button, if the icon is enabled. |
| /// Defaults to leaving this up to the [icon] widget. |
| /// |
| /// The icon is enabled if [onPressed] is not null. |
| /// |
| /// See also [disabledColor]. |
| /// |
| /// ```dart |
| /// new IconButton( |
| /// color: Colors.blue, |
| /// onPressed: _handleTap, |
| /// icon: Icons.widgets, |
| /// ), |
| /// ``` |
| 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 color to use for the icon inside the button, if the icon is disabled. |
| /// Defaults to the [ThemeData.disabledColor] of the current [Theme]. |
| /// |
| /// The icon is disabled if [onPressed] is null. |
| /// |
| /// See also [color]. |
| final Color disabledColor; |
| |
| /// 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; |
| |
| /// Text that describes the action that will occur when the button is pressed. |
| /// |
| /// This text is displayed when the user long-presses on the button and is |
| /// used for accessibility. |
| final String tooltip; |
| |
| @override |
| Widget build(BuildContext context) { |
| assert(debugCheckHasMaterial(context)); |
| Color currentColor; |
| if (onPressed != null) |
| currentColor = color; |
| else |
| currentColor = disabledColor ?? Theme.of(context).disabledColor; |
| |
| Widget result = new Semantics( |
| button: true, |
| enabled: onPressed != null, |
| child: new ConstrainedBox( |
| constraints: const BoxConstraints(minWidth: _kMinButtonSize, minHeight: _kMinButtonSize), |
| child: new Padding( |
| padding: padding, |
| child: new SizedBox( |
| height: iconSize, |
| width: iconSize, |
| child: new Align( |
| alignment: alignment, |
| child: IconTheme.merge( |
| data: new IconThemeData( |
| size: iconSize, |
| color: currentColor |
| ), |
| child: icon |
| ), |
| ), |
| ), |
| ), |
| ), |
| ); |
| |
| if (tooltip != null) { |
| result = new Tooltip( |
| message: tooltip, |
| child: result |
| ); |
| } |
| return new InkResponse( |
| onTap: onPressed, |
| child: result, |
| highlightColor: highlightColor ?? Theme.of(context).highlightColor, |
| splashColor: splashColor ?? Theme.of(context).splashColor, |
| radius: math.max( |
| Material.defaultSplashRadius, |
| (iconSize + math.min(padding.horizontal, padding.vertical)) * 0.7, |
| // x 0.5 for diameter -> radius and + 40% overflow derived from other Material apps. |
| ), |
| ); |
| } |
| |
| @override |
| void debugFillProperties(DiagnosticPropertiesBuilder properties) { |
| super.debugFillProperties(properties); |
| properties.add(new DiagnosticsProperty<Widget>('icon', icon, showName: false)); |
| properties.add(new ObjectFlagProperty<VoidCallback>('onPressed', onPressed, ifNull: 'disabled')); |
| properties.add(new StringProperty('tooltip', tooltip, defaultValue: null, quoted: false)); |
| } |
| } |