onMetricsChanged property

  1. @Deprecated('Use WidgetTester.platformDispatcher.onMetricsChanged instead. ' 'Deprecated to prepare for the upcoming multi-window support. ' 'This feature was deprecated after v3.9.0-0.1.pre.')
  2. @override
VoidCallback? onMetricsChanged
override

A callback that is invoked whenever the devicePixelRatio, physicalSize, padding, viewInsets, PlatformDispatcher.views, or systemGestureInsets values change.

Accessing this value returns the value contained in the PlatformDispatcher singleton, so instead of getting it from here, you should consider getting it from WidgetsBinding.instance.platformDispatcher instead (or, when WidgetsBinding isn't available, from PlatformDispatcher.instance). The reason this value forwards to the PlatformDispatcher is to provide convenience for applications that only use a single main window.

When using the Flutter framework, the MediaQuery widget exposes much of these metrics. Using MediaQuery.of to obtain them allows the framework to automatically rebuild widgets that depend on them, without having to manage the onMetricsChanged callback.

See PlatformDispatcher.onMetricsChanged for more information.

Implementation

@Deprecated(
  'Use WidgetTester.platformDispatcher.onMetricsChanged instead. '
  'Deprecated to prepare for the upcoming multi-window support. '
  'This feature was deprecated after v3.9.0-0.1.pre.'
)
@override
VoidCallback? get onMetricsChanged => platformDispatcher.onMetricsChanged;
  1. @Deprecated('Use WidgetTester.platformDispatcher.onMetricsChanged instead. ' 'Deprecated to prepare for the upcoming multi-window support. ' 'This feature was deprecated after v3.9.0-0.1.pre.')
  2. @override
void onMetricsChanged=(VoidCallback? callback)
override

Implementation

@Deprecated(
  'Use WidgetTester.platformDispatcher.onMetricsChanged instead. '
  'Deprecated to prepare for the upcoming multi-window support. '
  'This feature was deprecated after v3.9.0-0.1.pre.'
)
@override
set onMetricsChanged(VoidCallback? callback) {
  platformDispatcher.onMetricsChanged = callback;
}