add isRunning method to see if Lantern is already running in the back…

…ground

src/github.com/getlantern/lantern-mobile/app/src/main/java/org/getlantern/lantern/activity/LanternMainActivity.java

@@ -64,7 +64,9 @@ protected void onCreate(Bundle savedInstanceState) {
         // since onCreate is only called when the main activity
         // is first created, we clear shared preferences in case
         // Lantern was forcibly stopped during a previous run
-        LanternUI.clearPreferences();
+        if (!Service.isRunning(context)) {
+            LanternUI.clearPreferences();
+        }
 
         // the ACTION_SHUTDOWN intent is broadcast when the phone is
         // about to be shutdown. We register a receiver to make sure we
@@ -141,7 +143,6 @@ protected void onDestroy() {
             if (mReceiver != null) {
                 unregisterReceiver(mReceiver);
             }
-            stopLantern();
         } catch (Exception e) {
 
         }

src/github.com/getlantern/lantern-mobile/app/src/main/java/org/getlantern/lantern/vpn/Service.java

@@ -1,5 +1,8 @@
 package org.getlantern.lantern.vpn;
 
+import android.app.ActivityManager;
+import android.app.ActivityManager.RunningServiceInfo;
+import android.content.Context;
 import android.content.Intent;
 import android.util.Log;
 
@@ -27,6 +30,18 @@ public int onStartCommand(Intent intent, int flags, int startId) {
         return super.onStartCommand(intent, flags, startId);
     }
 
+    // isRunning checks to see if the VPN service is already running
+    // in the background.
+    public static boolean isRunning(Context c) {
+        ActivityManager manager = (ActivityManager)c.getSystemService(Context.ACTIVITY_SERVICE);
+        for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
+            if (Service.class.getName().equals(service.service.getClassName())) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     @Override
     public synchronized void run() {
         try {