build method
Describes the part of the user interface represented by this widget.
The framework calls this method when this widget is inserted into the tree in a given BuildContext and when the dependencies of this widget change (e.g., an InheritedWidget referenced by this widget changes). This method can potentially be called in every frame and should not have any side effects beyond building a widget.
The framework replaces the subtree below this widget with the widget returned by this method, either by updating the existing subtree or by removing the subtree and inflating a new subtree, depending on whether the widget returned by this method can update the root of the existing subtree, as determined by calling Widget.canUpdate.
Typically implementations return a newly created constellation of widgets that are configured with information from this widget's constructor and from the given BuildContext.
The given BuildContext contains information about the location in the tree at which this widget is being built. For example, the context provides the set of inherited widgets for this location in the tree. A given widget might be built with multiple different BuildContext arguments over time if the widget is moved around the tree or if the widget is inserted into the tree in multiple places at once.
The implementation of this method must only depend on:
- the fields of the widget, which themselves must not change over time, and
- any ambient state obtained from the
context
using BuildContext.dependOnInheritedWidgetOfExactType.
If a widget's build method is to depend on anything else, use a StatefulWidget instead.
See also:
- StatelessWidget, which contains the discussion on performance considerations.
Implementation
@override
widgets.Widget build(widgets.BuildContext context) => SvgPicture.string(
'''
<svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">
<path fill-rule="evenodd" clip-rule="evenodd" d="M2.25 3.6C2.25 2.85441 2.85442 2.25 3.6 2.25H20.4C21.1456 2.25 21.75 2.85442 21.75 3.6V20.4C21.75 21.1456 21.1456 21.75 20.4 21.75H3.6C2.85441 21.75 2.25 21.1456 2.25 20.4V3.6ZM12 6.25C12.4142 6.25 12.75 6.58579 12.75 7V13C12.75 13.4142 12.4142 13.75 12 13.75C11.5858 13.75 11.25 13.4142 11.25 13V7C11.25 6.58579 11.5858 6.25 12 6.25ZM12.5675 17.5008C12.8446 17.1929 12.8196 16.7187 12.5117 16.4416C12.2038 16.1645 11.7296 16.1894 11.4525 16.4973L11.4425 16.5084C11.1654 16.8163 11.1904 17.2905 11.4983 17.5676C11.8062 17.8447 12.2804 17.8197 12.5575 17.5119L12.5675 17.5008Z" fill="currentColor"/>
</svg>
''',
colorFilter:
color != null ? widgets.ColorFilter.mode(color!, widgets.BlendMode.srcIn) : null,
width: width,
height: height,
);