Bug 849847 - Make about:home scrollable with the analog stick. r=Cwiiis

mobile/android/base/BrowserApp.java

@@ -411,9 +411,9 @@ abstract public class BrowserApp extends GeckoApp
                 // put the focus on the layerview and carry on
                 if (mLayerView != null && !mLayerView.hasFocus() && GamepadUtils.isPanningControl(event)) {
                     if (mAboutHome.getUserVisibleHint()) {
-                        mLayerView.requestFocus();
-                    } else {
                         mAboutHome.requestFocus();
+                    } else {
+                        mLayerView.requestFocus();
                     }
                 }
                 return false;

mobile/android/base/Makefile.in

@@ -148,6 +148,7 @@ FENNEC_JAVA_FILES = \
   RemoteTabs.java \
   RobocopAPI.java \
   ServiceNotificationClient.java \
+  ScrollAnimator.java \
   SessionParser.java \
   SetupScreen.java \
   ShapedButton.java \

mobile/android/base/ScrollAnimator.java

@@ -0,0 +1,84 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko;
+
+import java.util.Timer;
+import java.util.TimerTask;
+
+import org.mozilla.gecko.util.GamepadUtils;
+
+import android.view.InputDevice;
+import android.view.MotionEvent;
+import android.view.View;
+
+public class ScrollAnimator implements View.OnGenericMotionListener {
+    private Timer mScrollTimer;
+    private int mX;
+    private int mY;
+
+    // Assuming 60fps, this will make the view scroll once per frame
+    static final long MS_PER_FRAME = 1000 / 60;
+
+    // Maximum number of pixels that can be scrolled per frame
+    static final float MAX_SCROLL = 0.075f * GeckoAppShell.getDpi();
+
+    private class ScrollRunnable extends TimerTask {
+        private View mView;
+
+        public ScrollRunnable(View view) {
+            mView = view;
+        }
+
+        @Override
+        public final void run() {
+            mView.scrollBy(mX, mY);
+        }
+    }
+
+    @Override
+    public boolean onGenericMotion(View view, MotionEvent event) {
+        if ((event.getSource() & InputDevice.SOURCE_CLASS_JOYSTICK) != 0) {
+            switch (event.getAction()) {
+            case MotionEvent.ACTION_MOVE:
+                // Cancel the animation if the joystick is in a neutral position
+                if (GamepadUtils.isValueInDeadZone(event, MotionEvent.AXIS_X) &&
+                        GamepadUtils.isValueInDeadZone(event, MotionEvent.AXIS_Y)) {
+                    if (mScrollTimer != null) {
+                        mScrollTimer.cancel();
+                        mScrollTimer = null;
+                    }
+                    return true;
+                }
+
+                // Scroll with a velocity relative to the screen DPI
+                mX = (int) (event.getAxisValue(MotionEvent.AXIS_X) * MAX_SCROLL);
+                mY = (int) (event.getAxisValue(MotionEvent.AXIS_Y) * MAX_SCROLL);
+
+                // Start the timer; the view will continue to scroll as long as
+                // the joystick is not in the deadzone.
+                if (mScrollTimer == null) {
+                    mScrollTimer = new Timer();
+                    ScrollRunnable task = new ScrollRunnable(view);
+                    mScrollTimer.scheduleAtFixedRate(task, 0, MS_PER_FRAME);
+                }
+
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Cancels the running scroll animation if it is in progress.
+     */
+    public void cancel() {
+        if (mScrollTimer != null) {
+            mScrollTimer.cancel();
+            mScrollTimer = null;
+        }
+    }
+}

mobile/android/base/widget/AboutHome.java

@@ -10,11 +10,13 @@ import java.util.EnumSet;
 import org.mozilla.gecko.GeckoApplication;
 import org.mozilla.gecko.LightweightTheme;
 import org.mozilla.gecko.R;
+import org.mozilla.gecko.ScrollAnimator;
 import org.mozilla.gecko.db.BrowserContract;
 
 import android.app.Activity;
 import android.content.res.Configuration;
 import android.database.ContentObserver;
+import android.os.Build;
 import android.os.Bundle;
 import android.support.v4.app.Fragment;
 import android.view.ContextMenu.ContextMenuInfo;
@@ -43,6 +45,7 @@ public class AboutHome extends Fragment {
     private LastTabsSection mLastTabsSection;
     private RemoteTabsSection mRemoteTabsSection;
     private TopSitesView mTopSitesView;
+    private ScrollAnimator mScrollAnimator;
 
     public interface UriLoadListener {
         public void onAboutHomeUriLoad(String uriSpec);
@@ -103,6 +106,13 @@ public class AboutHome extends Fragment {
         mAboutHomeView.setLightweightTheme(mLightweightTheme);
         mLightweightTheme.addListener(mAboutHomeView);
 
+        // ScrollAnimator implements the View.OnGenericMotionListener
+        // interface, which was added in API level 12.
+        if (Build.VERSION.SDK_INT >= 12) {
+            mScrollAnimator = new ScrollAnimator();
+            mAboutHomeView.setOnGenericMotionListener(mScrollAnimator);
+        }
+
         return mAboutHomeView;
     }
 
@@ -137,6 +147,11 @@ public class AboutHome extends Fragment {
         getActivity().getContentResolver().unregisterContentObserver(mTabsContentObserver);
         mTopSitesView.onDestroy();
 
+        if (mScrollAnimator != null) {
+            mScrollAnimator.cancel();
+        }
+        mScrollAnimator = null;
+
         mAboutHomeView = null;
         mAddonsSection = null;
         mLastTabsSection = null;