com.facebook.react.uimanager.ReactShadowNode#addChildAt ( )源码实例Demo

/**
 * Appends the child {@link ReactShadowNode} to the children set of the parent {@link
 * ReactShadowNode}.
 */
@Nullable
@DoNotStrip
public void appendChild(ReactShadowNode parent, ReactShadowNode child) {
  if (DEBUG) {
    FLog.d(TAG, "appendChild \n\tparent: " + parent + "\n\tchild: " + child);
  }
  SystraceMessage.beginSection(
    Systrace.TRACE_TAG_REACT_JAVA_BRIDGE,
    "FabricUIManager.appendChild")
    .flush();
  try {
    // If the child to append was already committed (child.isSealed()),
    // then we add a mutation of it. In the future this will be performed by FabricJS / Fiber.
    //TODO: T27926878 avoid cloning shared child
    if (child.isSealed()) {
      child = child.mutableCopy(child.getInstanceHandle());
    }
    parent.addChildAt(child, parent.getChildCount());
  } catch (Throwable t) {
    handleException(parent, t);
  } finally{
    Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
  }
}
 

@Test
public void testCloneNode() {
  ReactShadowNode node = createViewNode();
  ReactShadowNode child = createViewNode();
  node.addChildAt(child, 0);

  ReactShadowNode clonedNode = mFabricUIManager.cloneNode(node);

  assertThat(clonedNode).isNotSameAs(node);
  assertThat(clonedNode.getOriginalReactShadowNode()).isSameAs(node);
  assertSameFields(clonedNode, node);
  assertSameChildren(clonedNode, node);
  assertThat(clonedNode.getChildAt(0)).isEqualTo(child);
}
 

@Test
public void testCloneNodeWithNewChildren() {
  ReactShadowNode node = createViewNode();
  ReactShadowNode child = createViewNode();
  node.addChildAt(child, 0);

  ReactShadowNode clonedNode = mFabricUIManager.cloneNodeWithNewChildren(node);

  assertThat(clonedNode.getChildCount()).isZero();
  assertSameFields(clonedNode, node);
}