From 8b5e3fc16b1e58441318b6ada629dcff572dd120 Mon Sep 17 00:00:00 2001
From: David Vacca <dvacca@fb.com>
Date: Tue, 28 Aug 2018 22:49:26 -0700
Subject: [PATCH] Update size of Root ShadowNode when RootView changes its size

Summary: This diff updates the size of RootShadowNode and re-render RN views when the Size of the Android React View changes

Reviewed By: achen1

Differential Revision: D9173758

fbshipit-source-id: 7cc6bbfb646025c3ec1773ab041eb9207623af71
---
 .../com/facebook/react/ReactRootView.java     | 12 +++-------
 .../react/fabric/FabricUIManager.java         | 23 +++++++++++--------
 .../facebook/react/uimanager/PixelUtil.java   |  7 ++++++
 .../react/uimanager/UIManagerModule.java      | 12 +++++++---
 4 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java b/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
index 13ed88113..a07720cf8 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
@@ -408,16 +408,10 @@ public class ReactRootView extends SizeMonitoringFrameLayout
       return;
     }
     final ReactContext reactApplicationContext = mReactInstanceManager.getCurrentReactContext();
+
     if (reactApplicationContext != null) {
-      reactApplicationContext.runOnNativeModulesQueueThread(
-          new GuardedRunnable(reactApplicationContext) {
-            @Override
-            public void runGuarded() {
-              UIManagerHelper
-                .getUIManager(reactApplicationContext, getUIManagerType())
-                .updateRootLayoutSpecs(getRootViewTag(), widthMeasureSpec, heightMeasureSpec);
-            }
-          });
+      UIManagerHelper.getUIManager(reactApplicationContext, getUIManagerType())
+        .updateRootLayoutSpecs(getRootViewTag(), widthMeasureSpec, heightMeasureSpec);
     }
   }
 
diff --git a/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java b/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java
index 76c2ea8aa..2be6b50bf 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java
@@ -512,16 +512,21 @@ public class FabricUIManager implements UIManager, JSHandler, FabricBinder {
 
   @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;
-    }
+  public synchronized void updateRootLayoutSpecs(final int rootViewTag, final int widthMeasureSpec, final int heightMeasureSpec) {
+    mReactApplicationContext.runOnNativeModulesQueueThread(new Runnable() {
+      @Override
+      public void run() {
+        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);
+        ReactShadowNode newRootNode = rootNode.mutableCopy(rootNode.getInstanceHandle());
+        updateRootView(newRootNode, widthMeasureSpec, heightMeasureSpec);
+        mRootShadowNodeRegistry.replaceNode(newRootNode);
+      }
+    });
   }
 
   /**
diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/PixelUtil.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/PixelUtil.java
index 4f69c62e5..b8e4b0938 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/PixelUtil.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/PixelUtil.java
@@ -55,4 +55,11 @@ public class PixelUtil {
     return value / DisplayMetricsHolder.getWindowDisplayMetrics().density;
   }
 
+  /**
+   * @return {@link float} that represents the density of the display metrics for device screen.
+   */
+  public static float getDisplayMetricDensity() {
+    return DisplayMetricsHolder.getScreenDisplayMetrics().density;
+  }
+
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModule.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModule.java
index 43befc9ba..f20d8db1d 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModule.java
@@ -784,9 +784,15 @@ public class UIManagerModule extends ReactContextBaseJavaModule implements
    * Updates the styles of the {@link ReactShadowNode} based on the Measure specs received by
    * parameters.
    */
-  public void updateRootLayoutSpecs(int rootViewTag, int widthMeasureSpec, int heightMeasureSpec) {
-    mUIImplementation.updateRootView(rootViewTag, widthMeasureSpec, heightMeasureSpec);
-    mUIImplementation.dispatchViewUpdates(-1);
+  public void updateRootLayoutSpecs(final int rootViewTag, final int widthMeasureSpec, final int heightMeasureSpec) {
+    ReactApplicationContext reactApplicationContext = getReactApplicationContext();
+    reactApplicationContext.runOnNativeModulesQueueThread(
+      new GuardedRunnable(reactApplicationContext) {
+        @Override
+        public void runGuarded() {
+          mUIImplementation.updateRootView(rootViewTag, widthMeasureSpec, heightMeasureSpec);
+          mUIImplementation.dispatchViewUpdates(-1);
+        }});
   }
 
   /** Listener that drops the CSSNode pool on low memory when the app is backgrounded. */