Allow extending NativeViewHierarchyManager

Summary: public This diff makes a few small changes to NativeViewHierarchyManager to allow extending it:
a) makes the class public so it can be constructed from outside of the package
b) adds resolveView and resolveViewManager to access mTagsToViews and mTagsToViewManagers
c) changes addRootView signature to make root view a ViewGroup instead of SizeMonitoringFrameLayout

The reason behind change c) is that in FlatUIImplementation I want to use a root view that does not extend SizeMonitoringFrameLayout. NativeViewHierarchyManager doesn't really use any of the root view properties, so it could be even a View, but ViewGroup seems more fitting.

This diff should contain no functional changes or other side-effects.

Reviewed By: astreet

Differential Revision: D2554841

fb-gh-sync-id: cce748707cf7485d456e4a057dae1db87aa17160

ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java

@@ -56,7 +56,7 @@ import com.facebook.react.touch.JSResponderHandler;
  * TODO(5483031): Only dispatch updates when shadow views have changed
  */
 @NotThreadSafe
-/* package */ final class NativeViewHierarchyManager {
+public class NativeViewHierarchyManager {
 
   private final AnimationRegistry mAnimationRegistry;
   private final SparseArray<View> mTagsToViews;
@@ -74,6 +74,23 @@ import com.facebook.react.touch.JSResponderHandler;
     mRootTags = new SparseBooleanArray();
   }
 
+  protected final View resolveView(int tag) {
+    View view = mTagsToViews.get(tag);
+    if (view == null) {
+      throw new IllegalViewOperationException("Trying to resolve view with tag " + tag
+          + " which doesn't exist");
+    }
+    return view;
+  }
+
+  protected final ViewManager resolveViewManager(int tag) {
+    ViewManager viewManager = mTagsToViewManagers.get(tag);
+    if (viewManager == null) {
+      throw new IllegalViewOperationException("ViewManager for tag " + tag + " could not be found");
+    }
+    return viewManager;
+  }
+
   public AnimationRegistry getAnimationRegistry() {
     return mAnimationRegistry;
   }
@@ -81,32 +98,16 @@ import com.facebook.react.touch.JSResponderHandler;
   public void updateProperties(int tag, CatalystStylesDiffMap props) {
     UiThreadUtil.assertOnUiThread();
 
-    ViewManager viewManager = mTagsToViewManagers.get(tag);
+    ViewManager viewManager = resolveViewManager(tag);
-    if (viewManager == null) {
+    View viewToUpdate = resolveView(tag);
-      throw new IllegalViewOperationException("ViewManager for tag " + tag + " could not be found");
-    }
-
-    View viewToUpdate = mTagsToViews.get(tag);
-    if (viewToUpdate == null) {
-      throw new IllegalViewOperationException("Trying to update view with tag " + tag
-          + " which doesn't exist");
-    }
     viewManager.updateProperties(viewToUpdate, props);
   }
 
   public void updateViewExtraData(int tag, Object extraData) {
     UiThreadUtil.assertOnUiThread();
 
-    ViewManager viewManager = mTagsToViewManagers.get(tag);
+    ViewManager viewManager = resolveViewManager(tag);
-    if (viewManager == null) {
+    View viewToUpdate = resolveView(tag);
-      throw new IllegalViewOperationException("ViewManager for tag " + tag + " could not be found");
-    }
-
-    View viewToUpdate = mTagsToViews.get(tag);
-    if (viewToUpdate == null) {
-      throw new IllegalViewOperationException("Trying to update view with tag " + tag + " which " +
-          "doesn't exist");
-    }
     viewManager.updateExtraData(viewToUpdate, extraData);
   }
 
@@ -119,11 +120,7 @@ import com.facebook.react.touch.JSResponderHandler;
       int height) {
     UiThreadUtil.assertOnUiThread();
 
-    View viewToUpdate = mTagsToViews.get(tag);
+    View viewToUpdate = resolveView(tag);
-    if (viewToUpdate == null) {
-      throw new IllegalViewOperationException("Trying to update view with tag " + tag + " which " +
-          "doesn't exist");
-    }
 
     // Even though we have exact dimensions, we still call measure because some platform views (e.g.
     // Switch) assume that method will always be called before onLayout and onDraw. They use it to
@@ -257,10 +254,7 @@ import com.facebook.react.touch.JSResponderHandler;
       @Nullable ViewAtIndex[] viewsToAdd,
       @Nullable int[] tagsToDelete) {
     ViewGroup viewToManage = (ViewGroup) mTagsToViews.get(tag);
-    ViewGroupManager viewManager = (ViewGroupManager) mTagsToViewManagers.get(tag);
+    ViewGroupManager viewManager = (ViewGroupManager) resolveViewManager(tag);
-    if (viewManager == null) {
-      throw new IllegalViewOperationException("ViewManager for tag " + tag + " could not be found");
-    }
     if (viewToManage == null) {
       throw new IllegalViewOperationException("Trying to manageChildren view with tag " + tag +
         " which doesn't exist\n detail: " +
@@ -362,6 +356,13 @@ import com.facebook.react.touch.JSResponderHandler;
       int tag,
       SizeMonitoringFrameLayout view,
       ThemedReactContext themedContext) {
+    addRootViewGroup(tag, view, themedContext);
+  }
+
+  protected final void addRootViewGroup(
+      int tag,
+      ViewGroup view,
+      ThemedReactContext themedContext) {
     UiThreadUtil.assertOnUiThread();
     if (view.getId() != View.NO_ID) {
       throw new IllegalViewOperationException(
@@ -383,7 +384,7 @@ import com.facebook.react.touch.JSResponderHandler;
     UiThreadUtil.assertOnUiThread();
     if (!mRootTags.get(view.getId())) {
       // For non-root views we notify viewmanager with {@link ViewManager#onDropInstance}
-      Assertions.assertNotNull(mTagsToViewManagers.get(view.getId())).onDropViewInstance(
+      resolveViewManager(view.getId()).onDropViewInstance(
           (ThemedReactContext) view.getContext(),
           view);
     }
@@ -512,12 +513,7 @@ import com.facebook.react.touch.JSResponderHandler;
           "with tag " + reactTag);
     }
 
-    ViewManager viewManager = mTagsToViewManagers.get(reactTag);
+    ViewManager viewManager = resolveViewManager(reactTag);
-    if (viewManager == null) {
-      throw new IllegalViewOperationException(
-          "ViewManager for view tag " + reactTag + " could not be found");
-    }
-
     viewManager.receiveCommand(view, commandId, args);
   }