Add debug logging capabilities to ReactHorizontalScrollView

Summary:
When debugging this class a lot, I found it helpful to have these logs and it would have been nice if they were here already - I had to rewrite these several times.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D26836318

fbshipit-source-id: 08eb9ae19923fc593d1aba031586a02a193d6b2d

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollView.java

@@ -33,6 +33,7 @@
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.bridge.WritableNativeMap;
 import com.facebook.react.common.ReactConstants;
+import com.facebook.react.common.build.ReactBuildConfig;
 import com.facebook.react.modules.i18nmanager.I18nUtil;
 import com.facebook.react.uimanager.FabricViewStateManager;
 import com.facebook.react.uimanager.MeasureSpecAssertions;
@@ -50,6 +51,9 @@
 public class ReactHorizontalScrollView extends HorizontalScrollView
     implements ReactClippingViewGroup, FabricViewStateManager.HasFabricViewStateManager {
 
+  private static boolean DEBUG_MODE = false && ReactBuildConfig.DEBUG;
+  private static String TAG = ReactHorizontalScrollView.class.getSimpleName();
+
   private static @Nullable Field sScrollerField;
   private static boolean sTriedToGetScrollerField = false;
   private static final String CONTENT_OFFSET_LEFT = "contentOffsetLeft";
@@ -141,7 +145,7 @@ private OverScroller getOverScrollerFromParent() {
         sScrollerField.setAccessible(true);
       } catch (NoSuchFieldException e) {
         FLog.w(
-            ReactConstants.TAG,
+            TAG,
             "Failed to get mScroller field for HorizontalScrollView! "
                 + "This app will exhibit the bounce-back scrolling bug :(");
       }
@@ -154,7 +158,7 @@ private OverScroller getOverScrollerFromParent() {
           scroller = (OverScroller) scrollerValue;
         } else {
           FLog.w(
-              ReactConstants.TAG,
+              TAG,
               "Failed to cast mScroller field in HorizontalScrollView (probably due to OEM changes to AOSP)! "
                   + "This app will exhibit the bounce-back scrolling bug :(");
           scroller = null;
@@ -238,6 +242,10 @@ public void setOverflow(String overflow) {
 
   @Override
   protected void onDraw(Canvas canvas) {
+    if (DEBUG_MODE) {
+      FLog.i(TAG, "onDraw[%d]", getId());
+    }
+
     getDrawingRect(mRect);
 
     switch (mOverflow) {
@@ -255,12 +263,27 @@ protected void onDraw(Canvas canvas) {
   protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     MeasureSpecAssertions.assertExplicitMeasureSpec(widthMeasureSpec, heightMeasureSpec);
 
-    setMeasuredDimension(
-        MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.getSize(heightMeasureSpec));
+    int measuredWidth = MeasureSpec.getSize(widthMeasureSpec);
+    int measuredHeight = MeasureSpec.getSize(heightMeasureSpec);
+
+    if (DEBUG_MODE) {
+      FLog.i(
+          TAG,
+          "onMeasure[%d] measured width: %d measured height: %d",
+          getId(),
+          measuredWidth,
+          measuredHeight);
+    }
+
+    setMeasuredDimension(measuredWidth, measuredHeight);
   }
 
   @Override
   protected void onLayout(boolean changed, int l, int t, int r, int b) {
+    if (DEBUG_MODE) {
+      FLog.i(TAG, "onLayout[%d] l %d t %d r %d b %d", getId(), l, t, r, b);
+    }
+
     // Call with the present values in order to re-layout if necessary
     // If a "pending" value has been set, we restore that value.
     // That value gets cleared by reactScrollTo.
@@ -344,6 +367,10 @@ private void scrollToChild(View child) {
 
   @Override
   protected void onScrollChanged(int x, int y, int oldX, int oldY) {
+    if (DEBUG_MODE) {
+      FLog.i(TAG, "onScrollChanged[%d] x %d y %d oldx %d oldy %d", getId(), x, y, oldX, oldY);
+    }
+
     super.onScrollChanged(x, y, oldX, oldY);
 
     mActivelyScrolling = true;
@@ -573,6 +600,17 @@ public void setEndFillColor(int color) {
 
   @Override
   protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY) {
+    if (DEBUG_MODE) {
+      FLog.i(
+          TAG,
+          "onOverScrolled[%d] scrollX %d scrollY %d clampedX %d clampedY %d",
+          getId(),
+          scrollX,
+          scrollY,
+          clampedX,
+          clampedY);
+    }
+
     if (mScroller != null) {
       // FB SCROLLVIEW CHANGE
 
@@ -978,6 +1016,10 @@ public void setBorderStyle(@Nullable String style) {
    * scroll view and state. Calling raw `smoothScrollTo` doesn't update state.
    */
   public void reactSmoothScrollTo(int x, int y) {
+    if (DEBUG_MODE) {
+      FLog.i(TAG, "reactSmoothScrollTo[%d] x %d y %d", getId(), x, y);
+    }
+
     // `smoothScrollTo` contains some logic that, if called multiple times in a short amount of
     // time, will treat all calls as part of the same animation and will not lengthen the duration
     // of the animation. This means that, for example, if the user is scrolling rapidly, multiple
@@ -1034,6 +1076,10 @@ public void onAnimationRepeat(Animator animator) {}
    * scroll view and state. Calling raw `reactScrollTo` doesn't update state.
    */
   public void reactScrollTo(int x, int y) {
+    if (DEBUG_MODE) {
+      FLog.i(TAG, "reactScrollTo[%d] x %d y %d", getId(), x, y);
+    }
+
     scrollTo(x, y);
     updateStateOnScroll(x, y);
     setPendingContentOffsets(x, y);
@@ -1080,6 +1126,16 @@ private void updateStateOnScroll(final int scrollX, final int scrollY) {
       fabricScrollX = scrollX;
     }
 
+    if (DEBUG_MODE) {
+      FLog.i(
+          TAG,
+          "updateStateOnScroll[%d] scrollX %d scrollY %d fabricScrollX",
+          getId(),
+          scrollX,
+          scrollY,
+          fabricScrollX);
+    }
+
     mFabricViewStateManager.setState(
         new FabricViewStateManager.StateUpdateCallback() {
           @Override