Java Code Examples for com.facebook.litho.LithoView#layout()

/**
 * Mount a component tree into a component view.
 *
 * @param lithoView The view to mount the component tree into
 * @param componentTree The component tree to mount
 * @param widthSpec The width spec used to measure the resulting view
 * @param heightSpec The height spec used to measure the resulting view
 * @return A LithoView with the component tree mounted in it.
 */
public static LithoView mountComponent(
    LithoView lithoView, ComponentTree componentTree, int widthSpec, int heightSpec) {
  final boolean addParent = lithoView.getParent() == null;
  final ViewGroup parent =
      new ViewGroup(lithoView.getContext()) {
        @Override
        protected void onLayout(boolean changed, int l, int t, int r, int b) {}
      };

  if (addParent) {
    parent.addView(lithoView);
  }

  lithoView.setComponentTree(componentTree);

  try {
    Whitebox.invokeMethod(lithoView, "onAttach");
  } catch (Exception e) {
    throw new RuntimeException(e);
  }

  lithoView.measure(widthSpec, heightSpec);

  if (addParent) {
    parent.layout(0, 0, lithoView.getMeasuredWidth(), lithoView.getMeasuredHeight());
  }

  lithoView.layout(0, 0, lithoView.getMeasuredWidth(), lithoView.getMeasuredHeight());

  return lithoView;
}
 

@Test
public void
    animationTransitionsExtension_reUsingLithoViewWithDifferentComponentTrees_shouldNotCrash() {
  final boolean useExtensionsWithMountDelegate =
      ComponentsConfiguration.useExtensionsWithMountDelegate;
  ComponentsConfiguration.useExtensionsWithMountDelegate = true;

  ComponentContext componentContext = new ComponentContext(RuntimeEnvironment.application);

  mLithoViewRule.setRoot(getNonAnimatingComponent());
  // We measure and layout this non animating component to initialize the transition extension.
  mLithoViewRule.measure().layout();

  // We need an other litho view where we are going to measure and layout an other similar tree
  // (the real difference here is that the root components are not animating)
  LithoView lithoView = new LithoView(componentContext);
  ComponentTree nonAnimatingComponentTree = ComponentTree.create(componentContext).build();
  nonAnimatingComponentTree.setRoot(getNonAnimatingComponent());
  lithoView.setComponentTree(nonAnimatingComponentTree);
  lithoView.measure(LithoViewRule.DEFAULT_WIDTH_SPEC, LithoViewRule.DEFAULT_HEIGHT_SPEC);
  lithoView.layout(0, 0, lithoView.getMeasuredWidth(), lithoView.getMeasuredHeight());

  // Now we need a new component tree that will hold a component tree that holds an animating root
  // component.
  ComponentTree animatingComponentTree = ComponentTree.create(componentContext).build();
  animatingComponentTree.setRoot(getAnimatingXPropertyComponent());

  mLithoViewRule.useComponentTree(animatingComponentTree);
  // We measure this component tree so we initialize the mRootTransition in the extension, but we
  // end up not running a layout here.
  mLithoViewRule.measure();

  // Finally we set a new animating component tree to the initial litho view and run measure and
  // layout.
  mLithoViewRule.useComponentTree(nonAnimatingComponentTree);
  mLithoViewRule.measure().layout();
  // Should not crash.
  ComponentsConfiguration.useExtensionsWithMountDelegate = useExtensionsWithMountDelegate;
}
 

public LithoViewRule layout() {
  final LithoView lithoView = getLithoView();
  lithoView.layout(0, 0, lithoView.getMeasuredWidth(), lithoView.getMeasuredHeight());
  return this;
}