From c534e3bd5b4658ee1757bc448c6e3a31a27ef131 Mon Sep 17 00:00:00 2001
From: Kunhung Li <kunhungli@google.com>
Date: Tue, 16 Jul 2019 09:34:20 +0800
Subject: Fix UI disordered when starting activity in background

ViewPager can't get its actual height when updating in background.
Call super.onMeasure() at first to retrive child count and then call
setMeasuredDimension().

Bug: 135406087
Test: Manual test
Change-Id: I58430d01b324785d9d6f900d31791abf67ebceb2
---
 .../android/wallpaper/livepicker/widget/ConstraintViewPager.java   | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/com/android/wallpaper/livepicker/widget/ConstraintViewPager.java b/src/com/android/wallpaper/livepicker/widget/ConstraintViewPager.java
index 985cad6..f59b0b9 100644
--- a/src/com/android/wallpaper/livepicker/widget/ConstraintViewPager.java
+++ b/src/com/android/wallpaper/livepicker/widget/ConstraintViewPager.java
@@ -50,6 +50,8 @@ public class ConstraintViewPager extends ViewPager {
      */
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+
         int maxChildHeight = 0;
         int infoChildHeight = 0;
         int infoTopPadding = 0;
@@ -81,9 +83,6 @@ public class ConstraintViewPager extends ViewPager {
             }
         }
 
-        if (maxChildHeight != 0) {
-            heightMeasureSpec = MeasureSpec.makeMeasureSpec(maxChildHeight, MeasureSpec.EXACTLY);
-        }
-        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+        setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), maxChildHeight);
     }
 }
-- 
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