unregister receiver in SelectCurrentDbActivity, closes https://github.com/PhilippC/keepass2android/issues/1111

src/keepass2android/SelectCurrentDbActivity.cs

@@ -259,6 +259,16 @@ namespace keepass2android
 
         }
 
+        protected override void OnStop()
+        {
+            if (_intentReceiver != null)
+            {
+                UnregisterReceiver(_intentReceiver);
+                _intentReceiver = null;
+            }
+            base.OnStop();
+        }
+
         private bool GetIocFromViewIntent(Intent intent)
         {
             IOConnectionInfo ioc = new IOConnectionInfo();
@@ -437,6 +447,7 @@ namespace keepass2android
             //by leaving the app with the back button, the user probably wants to cancel the task
             //The activity might be resumed (through Android's recent tasks list), then use a NullTask:
             AppTask = new NullTask();
+            if (!IsFinishing)
                 Finish();
         }
 
@@ -497,10 +508,12 @@ namespace keepass2android
                 case KeePass.ExitCloseAfterTaskComplete:
                     // Do not lock the database
                     SetResult(KeePass.ExitCloseAfterTaskComplete);
+                    if (!IsFinishing)
                         Finish();
                     break;
                 case KeePass.ExitClose:
                     SetResult(KeePass.ExitClose);
+                    if (!IsFinishing)
                         Finish();
                     break;
                 case KeePass.ExitReloadDb: