Implement nice transitions for light status bar

- When the flag changes, apply an animation from the current value
- When the flag change is caused by an app transition, synchronize
  the status bar animation with the app transition animation.
  PhoneWindowManager calculates the timings based on some heuristics
  of the app transition animations and supplies these timings to
  StatusBarService.

Bug: 19233606
Change-Id: I4f99afba8f1eebb3524699ed4d7fbafee5463a37
diff --git a/services/core/java/com/android/server/policy/BarController.java b/services/core/java/com/android/server/policy/BarController.java
index bca2c16..e972ec7 100644
--- a/services/core/java/com/android/server/policy/BarController.java
+++ b/services/core/java/com/android/server/policy/BarController.java
@@ -43,15 +43,15 @@
 
     private static final int TRANSLUCENT_ANIMATION_DELAY_MS = 1000;
 
-    private final String mTag;
+    protected final String mTag;
     private final int mTransientFlag;
     private final int mUnhideFlag;
     private final int mTranslucentFlag;
     private final int mStatusBarManagerId;
     private final int mTranslucentWmFlag;
-    private final Handler mHandler;
+    protected final Handler mHandler;
     private final Object mServiceAquireLock = new Object();
-    private IStatusBarService mStatusBarService;
+    protected IStatusBarService mStatusBarService;
 
     private WindowState mWin;
     private int mState = StatusBarManager.WINDOW_STATE_SHOWING;
@@ -254,7 +254,7 @@
         }
     }
 
-    private IStatusBarService getStatusBarService() {
+    protected IStatusBarService getStatusBarService() {
         synchronized (mServiceAquireLock) {
             if (mStatusBarService == null) {
                 mStatusBarService = IStatusBarService.Stub.asInterface(
diff --git a/services/core/java/com/android/server/policy/PhoneWindowManager.java b/services/core/java/com/android/server/policy/PhoneWindowManager.java
index b90d263..f691b4e 100644
--- a/services/core/java/com/android/server/policy/PhoneWindowManager.java
+++ b/services/core/java/com/android/server/policy/PhoneWindowManager.java
@@ -74,6 +74,7 @@
 import android.util.DisplayMetrics;
 import android.util.EventLog;
 import android.util.Log;
+import android.util.Pair;
 import android.util.Slog;
 import android.util.SparseArray;
 import android.view.Display;
@@ -103,6 +104,8 @@
 import android.view.animation.Animation;
 import android.view.animation.AnimationSet;
 import android.view.animation.AnimationUtils;
+import android.view.animation.Interpolator;
+import android.view.animation.TranslateAnimation;
 
 import com.android.internal.R;
 import com.android.internal.statusbar.IStatusBarService;
@@ -724,12 +727,7 @@
     }
     MyOrientationListener mOrientationListener;
 
-    private final BarController mStatusBarController = new BarController("StatusBar",
-            View.STATUS_BAR_TRANSIENT,
-            View.STATUS_BAR_UNHIDE,
-            View.STATUS_BAR_TRANSLUCENT,
-            StatusBarManager.WINDOW_STATUS_BAR,
-            WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
+    private final StatusBarController mStatusBarController = new StatusBarController();
 
     private final BarController mNavigationBarController = new BarController("NavigationBar",
             View.NAVIGATION_BAR_TRANSIENT,
@@ -1359,6 +1357,9 @@
         if (!mPowerManager.isInteractive()) {
             goingToSleep(WindowManagerPolicy.OFF_BECAUSE_OF_USER);
         }
+
+        mWindowManagerInternal.registerAppTransitionListener(
+                mStatusBarController.getAppTransitionListener());
     }
 
     /**
diff --git a/services/core/java/com/android/server/policy/StatusBarController.java b/services/core/java/com/android/server/policy/StatusBarController.java
new file mode 100644
index 0000000..4d4ab44
--- /dev/null
+++ b/services/core/java/com/android/server/policy/StatusBarController.java
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.server.policy;
+
+import android.app.StatusBarManager;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.os.SystemClock;
+import android.util.Slog;
+import android.view.View;
+import android.view.WindowManager;
+import android.view.WindowManagerInternal;
+import android.view.animation.Animation;
+import android.view.animation.AnimationSet;
+import android.view.animation.Interpolator;
+import android.view.animation.TranslateAnimation;
+
+import com.android.internal.statusbar.IStatusBarService;
+
+import static android.view.WindowManagerInternal.*;
+
+/**
+ * Implements status bar specific behavior.
+ */
+public class StatusBarController extends BarController {
+
+    private static final long TRANSITION_DURATION = 120L;
+
+    private final AppTransitionListener mAppTransitionListener
+            = new AppTransitionListener() {
+
+        @Override
+        public void onAppTransitionPendingLocked() {
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        IStatusBarService statusbar = getStatusBarService();
+                        if (statusbar != null) {
+                            statusbar.appTransitionPending();
+                        }
+                    } catch (RemoteException e) {
+                        Slog.e(mTag, "RemoteException when app transition is pending", e);
+                        // re-acquire status bar service next time it is needed.
+                        mStatusBarService = null;
+                    }
+                }
+            });
+        }
+
+        @Override
+        public void onAppTransitionStartingLocked(IBinder openToken, IBinder closeToken,
+                final Animation openAnimation, final Animation closeAnimation) {
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        IStatusBarService statusbar = getStatusBarService();
+                        if (statusbar != null) {
+                            long startTime = calculateStatusBarTransitionStartTime(openAnimation,
+                                    closeAnimation);
+                            statusbar.appTransitionStarting(startTime, TRANSITION_DURATION);
+                        }
+                    } catch (RemoteException e) {
+                        Slog.e(mTag, "RemoteException when app transition is starting", e);
+                        // re-acquire status bar service next time it is needed.
+                        mStatusBarService = null;
+                    }
+                }
+            });
+        }
+
+        @Override
+        public void onAppTransitionCancelledLocked() {
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        IStatusBarService statusbar = getStatusBarService();
+                        if (statusbar != null) {
+                            statusbar.appTransitionCancelled();
+                        }
+                    } catch (RemoteException e) {
+                        Slog.e(mTag, "RemoteException when app transition is cancelled", e);
+                        // re-acquire status bar service next time it is needed.
+                        mStatusBarService = null;
+                    }
+                }
+            });
+        }
+    };
+
+    public StatusBarController() {
+        super("StatusBar",
+                View.STATUS_BAR_TRANSIENT,
+                View.STATUS_BAR_UNHIDE,
+                View.STATUS_BAR_TRANSLUCENT,
+                StatusBarManager.WINDOW_STATUS_BAR,
+                WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
+    }
+
+    public AppTransitionListener getAppTransitionListener() {
+        return mAppTransitionListener;
+    }
+
+    /**
+     * For a given app transition with {@code openAnimation} and {@code closeAnimation}, this
+     * calculates the timings for the corresponding status bar transition.
+     *
+     * @return the desired start time of the status bar transition, in uptime millis
+     */
+    private long calculateStatusBarTransitionStartTime(Animation openAnimation,
+            Animation closeAnimation) {
+        if (openAnimation != null && closeAnimation != null) {
+            TranslateAnimation openTranslateAnimation = findTranslateAnimation(openAnimation);
+            TranslateAnimation closeTranslateAnimation = findTranslateAnimation(closeAnimation);
+            if (openTranslateAnimation != null) {
+
+                // Some interpolators are extremely quickly mostly finished, but not completely. For
+                // our purposes, we need to find the fraction for which ther interpolator is mostly
+                // there, and use that value for the calculation.
+                float t = findAlmostThereFraction(openTranslateAnimation.getInterpolator());
+                return SystemClock.uptimeMillis()
+                        + openTranslateAnimation.getStartOffset()
+                        + (long)(openTranslateAnimation.getDuration()*t) - TRANSITION_DURATION;
+            } else if (closeTranslateAnimation != null) {
+                return SystemClock.uptimeMillis();
+            } else {
+                return SystemClock.uptimeMillis();
+            }
+        } else {
+            return SystemClock.uptimeMillis();
+        }
+    }
+
+    /**
+     * Tries to find a {@link TranslateAnimation} inside the {@code animation}.
+     *
+     * @return the found animation, {@code null} otherwise
+     */
+    private TranslateAnimation findTranslateAnimation(Animation animation) {
+        if (animation instanceof TranslateAnimation) {
+            return (TranslateAnimation) animation;
+        } else if (animation instanceof AnimationSet) {
+            AnimationSet set = (AnimationSet) animation;
+            for (int i = 0; i < set.getAnimations().size(); i++) {
+                Animation a = set.getAnimations().get(i);
+                if (a instanceof TranslateAnimation) {
+                    return (TranslateAnimation) a;
+                }
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Binary searches for a {@code t} such that there exists a {@code -0.01 < eps < 0.01} for which
+     * {@code interpolator(t + eps) > 0.99}.
+     */
+    private float findAlmostThereFraction(Interpolator interpolator) {
+        float val = 0.5f;
+        float adj = 0.25f;
+        while (adj >= 0.01f) {
+            if (interpolator.getInterpolation(val) < 0.99f) {
+                val += adj;
+            } else {
+                val -= adj;
+            }
+            adj /= 2;
+        }
+        return val;
+    }
+}
diff --git a/services/core/java/com/android/server/statusbar/StatusBarManagerService.java b/services/core/java/com/android/server/statusbar/StatusBarManagerService.java
index cf2ed07..f6df757 100644
--- a/services/core/java/com/android/server/statusbar/StatusBarManagerService.java
+++ b/services/core/java/com/android/server/statusbar/StatusBarManagerService.java
@@ -454,6 +454,35 @@
         }
     }
 
+    @Override
+    public void appTransitionPending() {
+        if (mBar != null) {
+            try {
+                mBar.appTransitionPending();
+            } catch (RemoteException ex) {}
+        }
+    }
+
+    @Override
+    public void appTransitionCancelled() {
+        if (mBar != null) {
+            try {
+                mBar.appTransitionCancelled();
+            } catch (RemoteException ex) {}
+        }
+    }
+
+    @Override
+    public void appTransitionStarting(long statusBarAnimationsStartTime,
+            long statusBarAnimationsDuration) {
+        if (mBar != null) {
+            try {
+                mBar.appTransitionStarting(
+                        statusBarAnimationsStartTime, statusBarAnimationsDuration);
+            } catch (RemoteException ex) {}
+        }
+    }
+
     private void enforceStatusBar() {
         mContext.enforceCallingOrSelfPermission(android.Manifest.permission.STATUS_BAR,
                 "StatusBarManagerService");
@@ -625,7 +654,6 @@
         }
     }
 
-
     // ================================================================================
     // Can be called from any thread
     // ================================================================================
diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 1852be2..de8a2fc 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -11619,5 +11619,12 @@
                 WindowManagerService.this.removeWindowToken(token);
             }
         }
+
+        @Override
+        public void registerAppTransitionListener(AppTransitionListener listener) {
+            synchronized (mWindowMap) {
+                mAppTransition.registerListenerLocked(listener);
+            }
+        }
     }
 }