1 | // Copyright 2014 The Flutter Authors. All rights reserved. |
2 | // Use of this source code is governed by a BSD-style license that can be |
3 | // found in the LICENSE file. |
4 | |
5 | import 'package:flutter/foundation.dart'; |
6 | |
7 | import 'basic.dart'; |
8 | import 'framework.dart'; |
9 | import 'icon_theme_data.dart'; |
10 | import 'inherited_theme.dart'; |
11 | |
12 | // Examples can assume: |
13 | // late BuildContext context; |
14 | |
15 | /// Controls the default properties of icons in a widget subtree. |
16 | /// |
17 | /// The icon theme is honored by [Icon] and [ImageIcon] widgets. |
18 | class IconTheme extends InheritedTheme { |
19 | /// Creates an icon theme that controls properties of descendant widgets. |
20 | const IconTheme({ |
21 | super.key, |
22 | required this.data, |
23 | required super.child, |
24 | }); |
25 | |
26 | /// Creates an icon theme that controls the properties of |
27 | /// descendant widgets, and merges in the current icon theme, if any. |
28 | static Widget merge({ |
29 | Key? key, |
30 | required IconThemeData data, |
31 | required Widget child, |
32 | }) { |
33 | return Builder( |
34 | builder: (BuildContext context) { |
35 | return IconTheme( |
36 | key: key, |
37 | data: _getInheritedIconThemeData(context).merge(data), |
38 | child: child, |
39 | ); |
40 | }, |
41 | ); |
42 | } |
43 | |
44 | /// The set of properties to use for icons in this subtree. |
45 | final IconThemeData data; |
46 | |
47 | /// The data from the closest instance of this class that encloses the given |
48 | /// context, if any. |
49 | /// |
50 | /// If there is no ambient icon theme, defaults to [IconThemeData.fallback]. |
51 | /// The returned [IconThemeData] is concrete (all values are non-null; see |
52 | /// [IconThemeData.isConcrete]). Any properties on the ambient icon theme that |
53 | /// are null get defaulted to the values specified on |
54 | /// [IconThemeData.fallback]. |
55 | /// |
56 | /// The [Theme] widget from the `material` library introduces an [IconTheme] |
57 | /// widget set to the [ThemeData.iconTheme], so in a Material Design |
58 | /// application, this will typically default to the icon theme from the |
59 | /// ambient [Theme]. |
60 | /// |
61 | /// Typical usage is as follows: |
62 | /// |
63 | /// ```dart |
64 | /// IconThemeData theme = IconTheme.of(context); |
65 | /// ``` |
66 | static IconThemeData of(BuildContext context) { |
67 | final IconThemeData iconThemeData = _getInheritedIconThemeData(context).resolve(context); |
68 | return iconThemeData.isConcrete |
69 | ? iconThemeData |
70 | : iconThemeData.copyWith( |
71 | size: iconThemeData.size ?? const IconThemeData.fallback().size, |
72 | fill: iconThemeData.fill ?? const IconThemeData.fallback().fill, |
73 | weight: iconThemeData.weight ?? const IconThemeData.fallback().weight, |
74 | grade: iconThemeData.grade ?? const IconThemeData.fallback().grade, |
75 | opticalSize: iconThemeData.opticalSize ?? const IconThemeData.fallback().opticalSize, |
76 | color: iconThemeData.color ?? const IconThemeData.fallback().color, |
77 | opacity: iconThemeData.opacity ?? const IconThemeData.fallback().opacity, |
78 | shadows: iconThemeData.shadows ?? const IconThemeData.fallback().shadows, |
79 | applyTextScaling: iconThemeData.applyTextScaling ?? const IconThemeData.fallback().applyTextScaling, |
80 | ); |
81 | } |
82 | |
83 | static IconThemeData _getInheritedIconThemeData(BuildContext context) { |
84 | final IconTheme? iconTheme = context.dependOnInheritedWidgetOfExactType<IconTheme>(); |
85 | return iconTheme?.data ?? const IconThemeData.fallback(); |
86 | } |
87 | |
88 | @override |
89 | bool updateShouldNotify(IconTheme oldWidget) => data != oldWidget.data; |
90 | |
91 | @override |
92 | Widget wrap(BuildContext context, Widget child) { |
93 | return IconTheme(data: data, child: child); |
94 | } |
95 | |
96 | @override |
97 | void debugFillProperties(DiagnosticPropertiesBuilder properties) { |
98 | super.debugFillProperties(properties); |
99 | data.debugFillProperties(properties); |
100 | } |
101 | } |
102 | |