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

/**
 * @return a clone of the {@link ReactShadowNode} received by parameter. The cloned
 *     ReactShadowNode will contain a copy of all the internal data of the original node,
 *     including its children set (note that the children nodes will not be cloned).
 */
@Nullable
@DoNotStrip
public ReactShadowNode cloneNode(ReactShadowNode node) {
  if (DEBUG) {
    FLog.d(TAG, "cloneNode \n\tnode: " + node);
  }
  SystraceMessage.beginSection(
    Systrace.TRACE_TAG_REACT_JAVA_BRIDGE,
    "FabricUIManager.cloneNode")
    .flush();
  try {
    ReactShadowNode clone = node.mutableCopy(node.getInstanceHandle());
    assertReactShadowNodeCopy(node, clone);
    return clone;
  } catch (Throwable t) {
    handleException(node, t);
    return null;
  } finally{
    Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
  }
}
 

/**
 * 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);
  }
}
 

/**
 * Updates the root view size and re-render the RN surface.
 *
 * //TODO: change synchronization to integrate with new #render loop.
 */
private synchronized void updateRootSize(int rootTag, int newWidth, int newHeight) {
  ReactShadowNode rootNode = getRootNode(rootTag);
  if (rootNode == null) {
    FLog.w(
      ReactConstants.TAG,
      "Tried to update size of non-existent tag: " + rootTag);
    return;
  }

  ReactShadowNode newRootNode = rootNode.mutableCopy(rootNode.getInstanceHandle());
  int newWidthSpec = View.MeasureSpec.makeMeasureSpec(newWidth, View.MeasureSpec.EXACTLY);
  int newHeightSpec = View.MeasureSpec.makeMeasureSpec(newHeight, View.MeasureSpec.EXACTLY);
  updateRootView(newRootNode, newWidthSpec, newHeightSpec);

  completeRoot(rootTag, newRootNode.getChildrenList());
}
 

/**
 * Tests that cloned text nodes will not share measure functions
 */
@Test
public void testTextMutableClone() {
  ReactRootView rootView =
      new ReactRootView(RuntimeEnvironment.application.getApplicationContext());
  int rootTag = mFabricUIManager.addRootView(rootView);
  ReactShadowNode text =
      mFabricUIManager.createNode(0, ReactTextViewManager.REACT_CLASS, rootTag, null, randomInstanceHandle());
  assertThat(text.isMeasureDefined()).isTrue();

  ReactShadowNode textCopy = text.mutableCopy(randomInstanceHandle());
  assertThat(textCopy.isMeasureDefined()).isTrue();

  textCopy.setStyleWidth(200);
  text.onBeforeLayout();
  text.calculateLayout();
  textCopy.onBeforeLayout();
  textCopy.calculateLayout();

  assertThat(text.getLayoutWidth()).isNotEqualTo(textCopy.getLayoutWidth());
}
 

@Override
@DoNotStrip
public synchronized void updateRootLayoutSpecs(int rootViewTag, int widthMeasureSpec, int heightMeasureSpec) {
  ReactShadowNode rootNode = getRootNode(rootViewTag);
  if (rootNode == null) {
    FLog.w(ReactConstants.TAG, "Tried to update non-existent root tag: " + rootViewTag);
    return;
  }

  ReactShadowNode newRootNode = rootNode.mutableCopy(rootNode.getInstanceHandle());
  updateRootView(newRootNode, widthMeasureSpec, heightMeasureSpec);
  mRootShadowNodeRegistry.replaceNode(newRootNode);
}