From f6fe26922653b45519d406bd07840719cef1d979 Mon Sep 17 00:00:00 2001
From: Paul Gardiner <paul.gardiner@artifex.com>
Date: Mon, 6 Jan 2014 12:24:27 +0000
Subject: Android: for scroll steps, use postOnAnimation when available

Using postOnAnimation in place of post noticably improves scroll
smoothness. Also avoid posting multiple runnables unnecessarily.
---
 .../src/com/artifex/mupdfdemo/ReaderView.java      | 20 ++++++-----
 .../android/src/com/artifex/mupdfdemo/Stepper.java | 42 ++++++++++++++++++++++
 2 files changed, 54 insertions(+), 8 deletions(-)
 create mode 100644 platform/android/src/com/artifex/mupdfdemo/Stepper.java

(limited to 'platform/android/src')

diff --git a/platform/android/src/com/artifex/mupdfdemo/ReaderView.java b/platform/android/src/com/artifex/mupdfdemo/ReaderView.java
index fe183945..c2093534 100644
--- a/platform/android/src/com/artifex/mupdfdemo/ReaderView.java
+++ b/platform/android/src/com/artifex/mupdfdemo/ReaderView.java
@@ -53,6 +53,7 @@ public class ReaderView
 	private final ScaleGestureDetector
 				  mScaleGestureDetector;
 	private final Scroller    mScroller;
+	private final Stepper     mStepper;
 	private int               mScrollerLastX;
 	private int               mScrollerLastY;
 	private boolean           mScrollDisabled;
@@ -66,6 +67,7 @@ public class ReaderView
 		mGestureDetector = new GestureDetector(this);
 		mScaleGestureDetector = new ScaleGestureDetector(context, this);
 		mScroller        = new Scroller(context);
+		mStepper = new Stepper(this, this);
 	}
 
 	public ReaderView(Context context, AttributeSet attrs) {
@@ -73,6 +75,7 @@ public class ReaderView
 		mGestureDetector = new GestureDetector(this);
 		mScaleGestureDetector = new ScaleGestureDetector(context, this);
 		mScroller        = new Scroller(context);
+		mStepper = new Stepper(this, this);
 	}
 
 	public ReaderView(Context context, AttributeSet attrs, int defStyle) {
@@ -80,6 +83,7 @@ public class ReaderView
 		mGestureDetector = new GestureDetector(this);
 		mScaleGestureDetector = new ScaleGestureDetector(context, this);
 		mScroller        = new Scroller(context);
+		mStepper = new Stepper(this, this);
 	}
 
 	public int getDisplayedViewIndex() {
@@ -203,7 +207,7 @@ public class ReaderView
 		}
 		mScrollerLastX = mScrollerLastY = 0;
 		mScroller.startScroll(0, 0, remainingX - xOffset, remainingY - yOffset, 400);
-		post(this);
+		mStepper.prod();
 	}
 
 	public void smartMoveBackwards() {
@@ -275,7 +279,7 @@ public class ReaderView
 		}
 		mScrollerLastX = mScrollerLastY = 0;
 		mScroller.startScroll(0, 0, remainingX - xOffset, remainingY - yOffset, 400);
-		post(this);
+		mStepper.prod();
 	}
 
 	public void resetupChildren() {
@@ -331,7 +335,7 @@ public class ReaderView
 			mScrollerLastX = x;
 			mScrollerLastY = y;
 			requestLayout();
-			post(this);
+			mStepper.prod();
 		}
 		else if (!mUserInteracting) {
 			// End of an inertial scroll and the user is not interacting.
@@ -395,7 +399,7 @@ public class ReaderView
 			if(withinBoundsInDirectionOfTravel(bounds, velocityX, velocityY)
 					&& expandedBounds.contains(0, 0)) {
 				mScroller.fling(0, 0, (int)velocityX, (int)velocityY, bounds.left, bounds.right, bounds.top, bounds.bottom);
-				post(this);
+				mStepper.prod();
 			}
 		}
 
@@ -536,7 +540,7 @@ public class ReaderView
 					postUnsettle(cv);
 					// post to invoke test for end of animation
 					// where we must set hq area for the new current view
-					post(this);
+					mStepper.prod();
 
 					onMoveOffChild(mCurrent);
 					mCurrent++;
@@ -547,7 +551,7 @@ public class ReaderView
 					postUnsettle(cv);
 					// post to invoke test for end of animation
 					// where we must set hq area for the new current view
-					post(this);
+					mStepper.prod();
 
 					onMoveOffChild(mCurrent);
 					mCurrent--;
@@ -592,7 +596,7 @@ public class ReaderView
 			}
 
 			// post to ensure generation of hq area
-			post(this);
+			mStepper.prod();
 		}
 
 		// Ensure current view is present
@@ -777,7 +781,7 @@ public class ReaderView
 		if (corr.x != 0 || corr.y != 0) {
 			mScrollerLastX = mScrollerLastY = 0;
 			mScroller.startScroll(0, 0, corr.x, corr.y, 400);
-			post(this);
+			mStepper.prod();
 		}
 	}
 
diff --git a/platform/android/src/com/artifex/mupdfdemo/Stepper.java b/platform/android/src/com/artifex/mupdfdemo/Stepper.java
new file mode 100644
index 00000000..d22240ef
--- /dev/null
+++ b/platform/android/src/com/artifex/mupdfdemo/Stepper.java
@@ -0,0 +1,42 @@
+package com.artifex.mupdfdemo;
+
+import android.annotation.SuppressLint;
+import android.os.Build;
+import android.view.View;
+
+public class Stepper {
+	protected final View mPoster;
+	protected final Runnable mTask;
+	protected boolean mPending;
+
+	public Stepper(View v, Runnable r) {
+		mPoster = v;
+		mTask = r;
+		mPending = false;
+	}
+
+	@SuppressLint("NewApi")
+	public void prod() {
+		if (!mPending) {
+			mPending = true;
+			if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
+				mPoster.postOnAnimation(new Runnable() {
+					@Override
+					public void run() {
+						mPending = false;
+						mTask.run();
+					}
+				});
+			} else {
+				mPoster.post(new Runnable() {
+					@Override
+					public void run() {
+						mPending = false;
+						mTask.run();
+					}
+				});
+
+			}
+		}
+	}
+}
-- 
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