From 33f825d4ef6f195b7b14e263122d65d02a203a9f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rui=20Ara=C3=BAjo?= <ruka.araujo@gmail.com>
Date: Thu, 6 Jul 2017 15:42:01 +0200
Subject: [PATCH] Fix Viewpager on Android when using native navigation.

---
 .../react/views/viewpager/ReactViewPager.java | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/viewpager/ReactViewPager.java b/ReactAndroid/src/main/java/com/facebook/react/views/viewpager/ReactViewPager.java
index 9a76bace545907..c2f3628e409cd3 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/views/viewpager/ReactViewPager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/views/viewpager/ReactViewPager.java
@@ -202,6 +202,26 @@ public void setScrollEnabled(boolean scrollEnabled) {
     mScrollEnabled = scrollEnabled;
   }
 
+
+  @Override
+  protected void onAttachedToWindow() {
+    super.onAttachedToWindow();
+    // The viewpager reset an internal flag on this method so we need to run another layout pass
+    // after attaching to window.
+    this.requestLayout();
+    post(measureAndLayout);
+  }
+
+  private final Runnable measureAndLayout = new Runnable() {
+    @Override
+    public void run() {
+      measure(
+              MeasureSpec.makeMeasureSpec(getWidth(), MeasureSpec.EXACTLY),
+              MeasureSpec.makeMeasureSpec(getHeight(), MeasureSpec.EXACTLY));
+      layout(getLeft(), getTop(), getRight(), getBottom());
+    }
+  };
+
   /*package*/ void addViewToAdapter(View child, int index) {
     getAdapter().addView(child, index);
   }