resetLayers method

Future<void> resetLayers()

Replaces the root layers of all managed renderViews with new, unused layers.

This method is typically used in a test's addTearDown to ensure that resources associated with the root transform layer are properly disposed of between tests. It is useful for tests that modify the view configuration (for example, by calling setSurfaceSize or changing ViewConfiguration). Such tests might cause the root layer to not be automatically disposed before the leak check, triggering false negatives.

This method also resets view configuration to its default value.

See also:

  • setSurfaceSize, which often necessitates calling this method during tear down.

Implementation

Future<void> resetLayers() async {
  await setSurfaceSize(null);
  for (final RenderView renderView in renderViews) {
    // To reliably trigger [RenderView.replaceRootLayer], we assign a new
    // device pixel ratio that differs from the current one.
    renderView.configuration = ViewConfiguration(
      devicePixelRatio: renderView.flutterView.devicePixelRatio + 1.0,
    );
    // Reset the device pixel ratio (and other view configurations) to their
    // default values.
    renderView.configuration = createViewConfigurationFor(renderView);
  }
}