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" stroke-width="1.5" fill="none" xmlns="http://www.w3.org/2000/svg">
<path d="M6.87172 3.42759L4.23172 12.2276C4.11623 12.6126 4.4045 13 4.80642 13L19.1936 13C19.5955 13 19.8838 12.6126 19.7683 12.2276L17.1283 3.42759C17.0521 3.1738 16.8185 3 16.5536 3L7.44642 3C7.18145 3 6.94786 3.1738 6.87172 3.42759Z" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round"/>
<path d="M12 17L12 15" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round"/>
<path d="M8.6 21H15.4C15.7314 21 15.9949 20.7315 15.9423 20.4043C15.763 19.2896 15.0263 17 12 17C8.97369 17 8.23702 19.2896 8.0577 20.4043C8.00506 20.7315 8.26863 21 8.6 21Z" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round"/>
</svg>
''',
colorFilter:
color != null ? widgets.ColorFilter.mode(color!, widgets.BlendMode.srcIn) : null,
width: width,
height: height,
);