Fixes several bugs in the lifecycle management of RosActivities.

Makes it possible to launch multiple RosActivities in the same process.

android_10/AndroidManifest.xml

@@ -1,25 +1,30 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="org.ros.android.android_10">
-    <uses-sdk android:targetSdkVersion="10" android:minSdkVersion="10"/>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.ros.android.android_10">
 
-    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
-    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
-    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
-    <uses-permission android:name="android.permission.WAKE_LOCK" />
+    <uses-sdk
+        android:minSdkVersion="10"
+        android:targetSdkVersion="10"/>
+
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
+    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>
+    <uses-permission android:name="android.permission.WAKE_LOCK"/>
+    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
 
     <application
         android:icon="@drawable/icon"
-        android:label="@string/app_name" >
+        android:label="@string/app_name">
         <activity
             android:name="MasterChooser"
             android:label="@string/app_name"
-            android:launchMode="singleTask" />
+            android:launchMode="singleTask"/>
 
-        <service android:name="org.ros.android.NodeMainExecutorService" >
+        <service android:name="org.ros.android.NodeMainExecutorService">
             <intent-filter>
-                <action android:name="org.ros.android.NodeMainExecutorService" />
+                <action android:name="org.ros.android.NodeMainExecutorService"/>
             </intent-filter>
         </service>
     </application>
 
-</manifest>
+</manifest>

android_10/src/org/ros/android/NodeMainExecutorService.java

@@ -18,17 +18,23 @@ package org.ros.android;
 
 import com.google.common.base.Preconditions;
 
+import android.app.AlertDialog;
 import android.app.Notification;
 import android.app.PendingIntent;
 import android.app.Service;
+import android.content.DialogInterface;
+import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
 import android.net.wifi.WifiManager;
 import android.net.wifi.WifiManager.WifiLock;
 import android.os.Binder;
+import android.os.Handler;
 import android.os.IBinder;
 import android.os.PowerManager;
 import android.os.PowerManager.WakeLock;
 import android.util.Log;
+import android.view.WindowManager;
+import android.widget.Toast;
 import org.ros.RosCore;
 import org.ros.android.android_10.R;
 import org.ros.concurrent.ListenerGroup;
@@ -63,6 +69,7 @@ public class NodeMainExecutorService extends Service implements NodeMainExecutor
   private final IBinder binder;
   private final ListenerGroup<NodeMainExecutorServiceListener> listeners;
 
+  private Handler handler;
   private WakeLock wakeLock;
   private WifiLock wifiLock;
   private RosCore rosCore;
@@ -89,6 +96,7 @@ public class NodeMainExecutorService extends Service implements NodeMainExecutor
 
   @Override
   public void onCreate() {
+    handler = new Handler();
     PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
     wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
     wakeLock.acquire();
@@ -127,20 +135,31 @@ public class NodeMainExecutorService extends Service implements NodeMainExecutor
 
   @Override
   public void shutdown() {
+    handler.post(new Runnable() {
+      @Override
+      public void run() {
+        AlertDialog.Builder builder = new AlertDialog.Builder(NodeMainExecutorService.this);
+        builder.setMessage("Continue shutting down?");
+        builder.setPositiveButton("Shutdown", new OnClickListener() {
+          @Override
+          public void onClick(DialogInterface dialog, int which) {
+            forceShutdown();
+          }
+        });
+        builder.setNegativeButton("Cancel", new OnClickListener() {
+          @Override
+          public void onClick(DialogInterface dialog, int which) {
+          }
+        });
+        AlertDialog alertDialog = builder.create();
+        alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
+        alertDialog.show();
+      }
+    });
+  }
+
+  public void forceShutdown() {
     signalOnShutdown();
-    // NOTE(damonkohler): This may be called multiple times. Shutting down a
-    // NodeMainExecutor multiple times is safe. It simply calls shutdown on all
-    // NodeMains.
-    nodeMainExecutor.shutdown();
-    if (rosCore != null) {
-      rosCore.shutdown();
-    }
-    if (wakeLock.isHeld()) {
-      wakeLock.release();
-    }
-    if (wifiLock.isHeld()) {
-      wifiLock.release();
-    }
     stopForeground(true);
     stopSelf();
   }
@@ -160,7 +179,17 @@ public class NodeMainExecutorService extends Service implements NodeMainExecutor
 
   @Override
   public void onDestroy() {
-    shutdown();
+    toast("Shutting down...");
+    nodeMainExecutor.shutdown();
+    if (rosCore != null) {
+      rosCore.shutdown();
+    }
+    if (wakeLock.isHeld()) {
+      wakeLock.release();
+    }
+    if (wifiLock.isHeld()) {
+      wifiLock.release();
+    }
     super.onDestroy();
   }
 
@@ -225,4 +254,13 @@ public class NodeMainExecutorService extends Service implements NodeMainExecutor
     }
     masterUri = rosCore.getUri();
   }
+
+  public void toast(final String text) {
+    handler.post(new Runnable() {
+      @Override
+      public void run() {
+        Toast.makeText(NodeMainExecutorService.this, text, Toast.LENGTH_SHORT).show();
+      }
+    });
+  }
 }

android_10/src/org/ros/android/RosActivity.java

@@ -24,7 +24,6 @@ import android.content.Intent;
 import android.content.ServiceConnection;
 import android.os.AsyncTask;
 import android.os.IBinder;
-import android.widget.Toast;
 import org.ros.exception.RosRuntimeException;
 import org.ros.node.NodeMain;
 import org.ros.node.NodeMainExecutor;
@@ -53,12 +52,18 @@ public abstract class RosActivity extends Activity {
       nodeMainExecutorService.addListener(new NodeMainExecutorServiceListener() {
         @Override
         public void onShutdown(NodeMainExecutorService nodeMainExecutorService) {
-          if ( !isFinishing() ) {
+          // We may have added multiple shutdown listeners and we only want to
+          // call finish() once.
+          if (!RosActivity.this.isFinishing()) {
             RosActivity.this.finish();
           }
         }
       });
-      startMasterChooser();
+      if (getMasterUri() == null) {
+        startMasterChooser();
+      } else {
+        init();
+      }
     }
 
     @Override
@@ -76,10 +81,10 @@ public abstract class RosActivity extends Activity {
   @Override
   protected void onStart() {
     super.onStart();
-    startNodeMainExecutorService();
+    bindNodeMainExecutorService();
   }
 
-  private void startNodeMainExecutorService() {
+  private void bindNodeMainExecutorService() {
     Intent intent = new Intent(this, NodeMainExecutorService.class);
     intent.setAction(NodeMainExecutorService.ACTION_START);
     intent.putExtra(NodeMainExecutorService.EXTRA_NOTIFICATION_TICKER, notificationTicker);
@@ -92,18 +97,22 @@ public abstract class RosActivity extends Activity {
 
   @Override
   protected void onDestroy() {
-    if (nodeMainExecutorService != null) {
-      nodeMainExecutorService.shutdown();
-      unbindService(nodeMainExecutorServiceConnection);
-      // NOTE(damonkohler): The activity could still be restarted. In that case,
-      // nodeMainExectuorService needs to be null for everything to be started
-      // up again.
-      nodeMainExecutorService = null;
-    }
-    Toast.makeText(this, notificationTitle + " shut down.", Toast.LENGTH_SHORT).show();
+    unbindService(nodeMainExecutorServiceConnection);
     super.onDestroy();
   }
 
+  private void init() {
+    // Run init() in a new thread as a convenience since it often requires
+    // network access.
+    new AsyncTask<Void, Void, Void>() {
+      @Override
+      protected Void doInBackground(Void... params) {
+        RosActivity.this.init(nodeMainExecutorService);
+        return null;
+      }
+    }.execute();
+  }
+
   /**
    * This method is called in a background thread once this {@link Activity} has
    * been initialized with a master {@link URI} via the {@link MasterChooser}
@@ -135,13 +144,12 @@ public abstract class RosActivity extends Activity {
 
   @Override
   protected void onActivityResult(int requestCode, int resultCode, Intent data) {
-    super.onActivityResult(requestCode, resultCode, data);
-    if (resultCode == RESULT_OK) {
-      if (requestCode == MASTER_CHOOSER_REQUEST_CODE) {
+    if (requestCode == MASTER_CHOOSER_REQUEST_CODE) {
+      if (resultCode == RESULT_OK) {
         if (data.getBooleanExtra("NEW_MASTER", false) == true) {
           AsyncTask<Boolean, Void, URI> task = new AsyncTask<Boolean, Void, URI>() {
             @Override
-            protected URI doInBackground(Boolean[] params) {
+            protected URI doInBackground(Boolean... params) {
               RosActivity.this.nodeMainExecutorService.startMaster(params[0]);
               return RosActivity.this.nodeMainExecutorService.getMasterUri();
             }
@@ -163,20 +171,12 @@ public abstract class RosActivity extends Activity {
           }
           nodeMainExecutorService.setMasterUri(uri);
         }
-        // Run init() in a new thread as a convenience since it often requires
-        // network access.
-        new AsyncTask<Void, Void, Void>() {
-          @Override
-          protected Void doInBackground(Void... params) {
-            RosActivity.this.init(nodeMainExecutorService);
-            return null;
-          }
-        }.execute();
+        init();
       } else {
         // Without a master URI configured, we are in an unusable state.
-        nodeMainExecutorService.shutdown();
-        finish();
+        nodeMainExecutorService.forceShutdown();
       }
     }
+    super.onActivityResult(requestCode, resultCode, data);
   }
 }