Check shortcut action for null

app/src/main/java/org/traccar/client/ShortcutActivity.java

@@ -93,6 +93,7 @@ public class ShortcutActivity extends Activity {
         } else {
             action = intent.getStringExtra(EXTRA_ACTION);
         }
+        if (action != null) {
             switch (action) {
                 case EXTRA_ACTION_START:
                     PreferenceManager.getDefaultSharedPreferences(this)
@@ -110,6 +111,7 @@ public class ShortcutActivity extends Activity {
                     sendAlarm();
                     break;
             }
+        }
         finish();
     }