android: Improve ActivityStatus and add ChromiumActivity.

The ActivityStatus class used to track activity state changes is too basic
for some usage scenarios.

This patch does the following:

- Augment ActivityStatus with a new StateListener type that can be
  registered to listen to all activity state changes.

  Also add getActivity(), getState(), registerStateListener()
  and unregisterStateListener() as static method.

- Add a new ChromiumActivity class that all Chromium main activities
  should sub-class, to ensure that the ActivityStatus state is updated
  appropriately.

- Modify all main activities in the Chromium code base to extend
  from ChromiumActivity instead of Activity.

BUG=none


Review URL: https://chromiumcodereview.appspot.com/11419287

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171789 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 191 insertions, 43 deletions

diff --git a/base/android/java/src/org/chromium/base/ActivityStatus.java b/base/android/java/src/org/chromium/base/ActivityStatus.java
index 765d841..b80c149 100644
--- a/base/android/java/src/org/chromium/base/ActivityStatus.java
+++ b/base/android/java/src/org/chromium/base/ActivityStatus.java
@@ -4,6 +4,7 @@
 
 package org.chromium.base;
 
+import android.app.Activity;
 import android.os.Looper;
 
 import java.util.ArrayList;
@@ -12,55 +13,137 @@ import java.util.ArrayList;
  * Provides information about the parent activity's status.
  */
 public class ActivityStatus {
+
+    // Constants matching activity states reported to StateListener.onStateChange
+    public static final int CREATED = 1;
+    public static final int STARTED = 2;
+    public static final int RESUMED = 3;
+    public static final int PAUSED = 4;
+    public static final int STOPPED = 5;
+    public static final int DESTROYED = 6;
+
+    // Current main activity, or null if none.
+    private static Activity sActivity;
+
+    // Current main activity's state. This can be set even if sActivity
+    // is null, to simplify unit testing.
+    private static int sActivityState;
+
+    // Current activity instance, or null.
+    private static ActivityStatus sInstance;
+
+    // List of pause/resume listeners.
+    private final ArrayList<Listener> mListeners;
+
+    // List of state listeners.
+    private final ArrayList<StateListener> mStateListeners;
+
+    protected ActivityStatus() {
+        mListeners = new ArrayList<Listener>();
+        mStateListeners = new ArrayList<StateListener>();
+    }
+
+    /**
+     * Must be called by the main activity when it changes state.
+     * @param activity Current activity.
+     * @param newState New state value.
+     */
+    public static void onStateChange(Activity activity, int newState) {
+        if (newState == CREATED) {
+            sActivity = activity;
+        }
+        sActivityState = newState;
+        getInstance().changeState(newState);
+
+        if (newState == DESTROYED) {
+            sActivity = null;
+        }
+    }
+
+    private void changeState(int newState) {
+        for (StateListener listener : mStateListeners) {
+            listener.onActivityStateChange(newState);
+        }
+        if (newState == PAUSED || newState == RESUMED) {
+            boolean paused = (newState == PAUSED);
+            for (Listener listener : mListeners) {
+                listener.onActivityStatusChanged(paused);
+            }
+        }
+    }
+
+    // This interface can only be used to listen to PAUSED and RESUMED
+    // events. Deprecated, new code should use StateListener instead.
+    // TODO(digit): Remove once all users have switched to StateListener.
+    @Deprecated
     public interface Listener {
         /**
-         * Called when the activity's status changes.
+         * Called when the activity is paused or resumed only.
          * @param isPaused true if the activity is paused, false if not.
          */
         public void onActivityStatusChanged(boolean isPaused);
     }
 
-    private boolean mIsPaused = false;
-    private ArrayList<Listener> mListeners = new ArrayList<Listener>();
-    private static ActivityStatus sActivityStatus;
-
-    private ActivityStatus() {
+    // Use this interface to listen to all state changes.
+    public interface StateListener {
+        /**
+         * Called when the activity's state changes.
+         * @param newState New activity state.
+         */
+        public void onActivityStateChange(int newState);
     }
 
+    /**
+     * Returns the current ActivityStatus instance.
+     */
     public static ActivityStatus getInstance() {
         // Can only be called on the UI thread.
         assert Looper.myLooper() == Looper.getMainLooper();
-        if (sActivityStatus == null) {
-            sActivityStatus = new ActivityStatus();
+        if (sInstance == null) {
+            sInstance = new ActivityStatus();
         }
-        return sActivityStatus;
+        return sInstance;
     }
 
     /**
      * Indicates that the parent activity was paused.
      */
     public void onPause() {
-        mIsPaused = true;
-        informAllListeners();
+       changeState(PAUSED);
     }
 
     /**
      * Indicates that the parent activity was resumed.
      */
     public void onResume() {
-        mIsPaused = false;
-        informAllListeners();
+        changeState(RESUMED);
     }
 
     /**
      * Indicates that the parent activity is currently paused.
      */
     public boolean isPaused() {
-        return mIsPaused;
+        return sActivityState == PAUSED;
+    }
+
+    /**
+     * Returns the current main application activity.
+     */
+    public static Activity getActivity() {
+        return sActivity;
+    }
+
+    /**
+     * Returns the current main application activity's state.
+     */
+    public static int getState() {
+        // To simplify unit testing, don't check sActivity for null.
+        return sActivityState;
     }
 
     /**
-     * Registers the given listener to receive activity status updates.
+     * Registers the given pause/resume listener to receive activity
+     * status updates. Use registerStateListener() instead.
      * @param listener Listener to receive status updates.
      */
     public void registerListener(Listener listener) {
@@ -68,16 +151,29 @@ public class ActivityStatus {
     }
 
     /**
-     * Unregisters the given listener from receiving activity status updates.
+     * Unregisters the given pause/resume listener from receiving activity
+     * status updates. Use unregisterStateListener() instead.
      * @param listener Listener that doesn't want to receive status updates.
      */
     public void unregisterListener(Listener listener) {
         mListeners.remove(listener);
     }
 
-    private void informAllListeners() {
-        for (Listener listener : mListeners) {
-            listener.onActivityStatusChanged(mIsPaused);
-        }
+    /**
+     * Registers the given listener to receive activity state changes.
+     * @param listener Listener to receive state changes.
+     */
+    public static void registerStateListener(StateListener listener) {
+        ActivityStatus status = getInstance();
+        status.mStateListeners.add(listener);
+    }
+
+    /**
+     * Unregisters the given listener from receiving activity state changes.
+     * @param listener Listener that doesn't want to receive state changes.
+     */
+    public static void unregisterStateListener(StateListener listener) {
+        ActivityStatus status = getInstance();
+        status.mStateListeners.remove(listener);
     }
 }
diff --git a/base/android/java/src/org/chromium/base/ChromiumActivity.java b/base/android/java/src/org/chromium/base/ChromiumActivity.java
new file mode 100644
index 0000000..f857e12
--- /dev/null
+++ b/base/android/java/src/org/chromium/base/ChromiumActivity.java
@@ -0,0 +1,50 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base;
+
+import android.app.Activity;
+import android.os.Bundle;
+
+// All Chromium main activities should extend this class.
+// This allows various sub-systems to properly react to activity
+// state changes.
+public class ChromiumActivity extends Activity {
+
+  @Override
+  protected void onCreate(Bundle savedInstance) {
+    super.onCreate(savedInstance);
+    ActivityStatus.onStateChange(this, ActivityStatus.CREATED);
+  }
+
+  @Override
+  protected void onStart() {
+    super.onStart();
+    ActivityStatus.onStateChange(this, ActivityStatus.STARTED);
+  }
+
+  @Override
+  protected void onResume() {
+    super.onResume();
+    ActivityStatus.onStateChange(this, ActivityStatus.STARTED);
+  }
+
+  @Override
+  protected void onPause() {
+    ActivityStatus.onStateChange(this, ActivityStatus.STARTED);
+    super.onPause();
+  }
+
+  @Override
+  protected void onStop() {
+    ActivityStatus.onStateChange(this, ActivityStatus.STARTED);
+    super.onStop();
+  }
+
+  @Override
+  protected void onDestroy() {
+    ActivityStatus.onStateChange(this, ActivityStatus.DESTROYED);
+    super.onDestroy();
+  }
+}
diff --git a/chrome/android/testshell/java/src/org/chromium/chrome/testshell/ChromiumTestShellActivity.java b/chrome/android/testshell/java/src/org/chromium/chrome/testshell/ChromiumTestShellActivity.java
index 68f9f04..e754bb8 100644
--- a/chrome/android/testshell/java/src/org/chromium/chrome/testshell/ChromiumTestShellActivity.java
+++ b/chrome/android/testshell/java/src/org/chromium/chrome/testshell/ChromiumTestShellActivity.java
@@ -11,6 +11,7 @@ import android.text.TextUtils;
 import android.util.Log;
 import android.view.KeyEvent;
 
+import org.chromium.base.ChromiumActivity;
 import org.chromium.chrome.browser.DevToolsServer;
 import org.chromium.chrome.browser.TabBase;
 import org.chromium.content.app.LibraryLoader;
@@ -22,7 +23,7 @@ import org.chromium.ui.gfx.ActivityNativeWindow;
 /**
  * The {@link Activity} component of a basic test shell to test Chrome features.
  */
-public class ChromiumTestShellActivity extends Activity {
+public class ChromiumTestShellActivity extends ChromiumActivity {
     private static final String TAG = ChromiumTestShellActivity.class.getCanonicalName();
     private static final String COMMAND_LINE_FILE =
             "/data/local/tmp/chromium-testshell-command-line";
diff --git a/content/public/android/java/src/org/chromium/content/browser/LocationProvider.java b/content/public/android/java/src/org/chromium/content/browser/LocationProvider.java
index 75be3dd..6efcb95 100644
--- a/content/public/android/java/src/org/chromium/content/browser/LocationProvider.java
+++ b/content/public/android/java/src/org/chromium/content/browser/LocationProvider.java
@@ -37,7 +37,7 @@ class LocationProvider {
      * ensures that the start/stop calls into this class are done in the UI thread.
      */
     private static class LocationProviderImpl
-            implements LocationListener, ActivityStatus.Listener {
+            implements LocationListener, ActivityStatus.StateListener {
 
         private Context mContext;
         private LocationManager mLocationManager;
@@ -49,11 +49,11 @@ class LocationProvider {
             mContext = context;
         }
 
-        public void onActivityStatusChanged(boolean isPaused) {
-            if (isPaused) {
+        public void onActivityStateChange(int state) {
+            if (state == ActivityStatus.PAUSED) {
                 mShouldRunAfterActivityResume = mIsRunning;
                 unregisterFromLocationUpdates();
-            } else {
+            } else if (state == ActivityStatus.RESUMED) {
                 assert !mIsRunning;
                 if (mShouldRunAfterActivityResume) {
                     registerForLocationUpdates();
@@ -68,7 +68,7 @@ class LocationProvider {
         private void start(boolean gpsEnabled) {
             if (!mIsRunning && !mShouldRunAfterActivityResume) {
                 // Currently idle so start listening to activity status changes.
-                ActivityStatus.getInstance().registerListener(this);
+                ActivityStatus.registerStateListener(this);
             }
             mIsGpsEnabled = gpsEnabled;
             if (ActivityStatus.getInstance().isPaused()) {
@@ -84,7 +84,7 @@ class LocationProvider {
          */
         private void stop() {
             unregisterFromLocationUpdates();
-            ActivityStatus.getInstance().unregisterListener(this);
+            ActivityStatus.unregisterStateListener(this);
             mShouldRunAfterActivityResume = false;
         }
 
diff --git a/content/public/android/javatests/src/org/chromium/content/browser/LocationProviderTest.java b/content/public/android/javatests/src/org/chromium/content/browser/LocationProviderTest.java
index 0fa6c06..5dde1f2 100644
--- a/content/public/android/javatests/src/org/chromium/content/browser/LocationProviderTest.java
+++ b/content/public/android/javatests/src/org/chromium/content/browser/LocationProviderTest.java
@@ -60,9 +60,9 @@ public class LocationProviderTest extends InstrumentationTestCase {
     public void testStartPauseResumeStop() throws Exception {
         mLocationProvider.start(false);
         assertTrue("Should be running", mLocationProvider.isRunning());
-        ActivityStatus.getInstance().onPause();
+        ActivityStatus.onStateChange(null, ActivityStatus.PAUSED);
         assertFalse("Should have paused", mLocationProvider.isRunning());
-        ActivityStatus.getInstance().onResume();
+        ActivityStatus.onStateChange(null, ActivityStatus.RESUMED);
         assertTrue("Should have resumed", mLocationProvider.isRunning());
         mLocationProvider.stop();
         assertFalse("Should have stopped", mLocationProvider.isRunning());
@@ -76,10 +76,10 @@ public class LocationProviderTest extends InstrumentationTestCase {
     @UiThreadTest
     @Feature({"Location"})
     public void testPauseStartResumeStop() throws Exception {
-        ActivityStatus.getInstance().onPause();
+        ActivityStatus.onStateChange(null, ActivityStatus.PAUSED);
         mLocationProvider.start(false);
         assertFalse("Should not be running", mLocationProvider.isRunning());
-        ActivityStatus.getInstance().onResume();
+        ActivityStatus.onStateChange(null, ActivityStatus.RESUMED);
         assertTrue("Should have resumed", mLocationProvider.isRunning());
         mLocationProvider.stop();
         assertFalse("Should have stopped", mLocationProvider.isRunning());
@@ -94,11 +94,11 @@ public class LocationProviderTest extends InstrumentationTestCase {
     public void testStartPauseUpgradeResumeStop() throws Exception {
         mLocationProvider.start(false);
         assertTrue("Should be running", mLocationProvider.isRunning());
-        ActivityStatus.getInstance().onPause();
+        ActivityStatus.onStateChange(null, ActivityStatus.PAUSED);
         assertFalse("Should have paused", mLocationProvider.isRunning());
         mLocationProvider.start(true);
         assertFalse("Should be paused", mLocationProvider.isRunning());
-        ActivityStatus.getInstance().onResume();
+        ActivityStatus.onStateChange(null, ActivityStatus.RESUMED);
         assertTrue("Should have resumed", mLocationProvider.isRunning());
         mLocationProvider.stop();
         assertFalse("Should have stopped", mLocationProvider.isRunning());
diff --git a/content/shell/android/java/src/org/chromium/content_shell/ContentShellActivity.java b/content/shell/android/java/src/org/chromium/content_shell/ContentShellActivity.java
index 22456af..bddb70f 100644
--- a/content/shell/android/java/src/org/chromium/content_shell/ContentShellActivity.java
+++ b/content/shell/android/java/src/org/chromium/content_shell/ContentShellActivity.java
@@ -11,6 +11,7 @@ import android.text.TextUtils;
 import android.util.Log;
 import android.view.KeyEvent;
 
+import org.chromium.base.ChromiumActivity;
 import org.chromium.content.app.LibraryLoader;
 import org.chromium.content.browser.ActivityContentVideoViewDelegate;
 import org.chromium.content.browser.ContentVideoView;
@@ -22,7 +23,7 @@ import org.chromium.ui.gfx.ActivityNativeWindow;
 /**
  * Activity for managing the Content Shell.
  */
-public class ContentShellActivity extends Activity {
+public class ContentShellActivity extends ChromiumActivity {
 
     public static final String COMMAND_LINE_FILE = "/data/local/tmp/content-shell-command-line";
     private static final String TAG = ContentShellActivity.class.getName();
diff --git a/net/android/java/src/org/chromium/net/NetworkChangeNotifierAutoDetect.java b/net/android/java/src/org/chromium/net/NetworkChangeNotifierAutoDetect.java
index c5fd033..90aa753 100644
--- a/net/android/java/src/org/chromium/net/NetworkChangeNotifierAutoDetect.java
+++ b/net/android/java/src/org/chromium/net/NetworkChangeNotifierAutoDetect.java
@@ -21,7 +21,7 @@ import org.chromium.base.ActivityStatus;
  * ACCESS_NETWORK_STATE permission.
  */
 public class NetworkChangeNotifierAutoDetect extends BroadcastReceiver
-        implements ActivityStatus.Listener {
+        implements ActivityStatus.StateListener {
 
     /** Queries the ConnectivityManager for information about the current connection. */
     static class ConnectivityManagerDelegate {
@@ -73,11 +73,10 @@ public class NetworkChangeNotifierAutoDetect extends BroadcastReceiver
         mConnectivityManagerDelegate = new ConnectivityManagerDelegate(context);
         mConnectionType = currentConnectionType(context);
 
-        ActivityStatus status = ActivityStatus.getInstance();
-        if (!status.isPaused()) {
+        if (ActivityStatus.getState() != ActivityStatus.PAUSED) {
           registerReceiver();
         }
-        status.registerListener(this);
+        ActivityStatus.registerStateListener(this);
     }
 
     /**
@@ -168,12 +167,12 @@ public class NetworkChangeNotifierAutoDetect extends BroadcastReceiver
         }
     }
 
-    // AcitivityStatus.Listener
+    // ActivityStatus.StateListener
     @Override
-    public void onActivityStatusChanged(boolean isPaused) {
-        if (isPaused) {
+    public void onActivityStateChange(int state) {
+        if (state == ActivityStatus.PAUSED) {
             unregisterReceiver();
-        } else {
+        } else if (state == ActivityStatus.RESUMED) {
             registerReceiver();
         }
     }
diff --git a/testing/android/java/src/org/chromium/native_test/ChromeNativeTestActivity.java b/testing/android/java/src/org/chromium/native_test/ChromeNativeTestActivity.java
index 77022506..fef3dce 100644
--- a/testing/android/java/src/org/chromium/native_test/ChromeNativeTestActivity.java
+++ b/testing/android/java/src/org/chromium/native_test/ChromeNativeTestActivity.java
@@ -11,6 +11,7 @@ import android.os.Environment;
 import android.os.Handler;
 import android.util.Log;
 
+import org.chromium.base.ChromiumActivity;
 import org.chromium.base.PathUtils;
 import org.chromium.base.SystemMonitor;
 
@@ -19,7 +20,7 @@ import java.io.File;
 // Android's NativeActivity is mostly useful for pure-native code.
 // Our tests need to go up to our own java classes, which is not possible using
 // the native activity class loader.
-public class ChromeNativeTestActivity extends Activity {
+public class ChromeNativeTestActivity extends ChromiumActivity {
     private final String TAG = "ChromeNativeTestActivity";
     private final String EXTRA_RUN_IN_SUB_THREAD = "RunInSubThread";
     // We post a delayed task to run tests so that we do not block onCreate().