Accessing main activity in Broadcast Reciever without using intent

Question

I am stuck in a problem. I have a broadcast receiver that calls the method of class takes in context and main activity reference in constructor. I dont know how to access main activity in broadcast receiver.Here is my code:

public void onReceive(@NonNull Context context, @NonNull Intent intent) {
        if (context == null) {
            throw new IllegalArgumentException();
        }
        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = cm.getActiveNetworkInfo();

        if (info != null) {
            if (info.isConnected()) { 
                if (info.getType() == ConnectivityManager.TYPE_WIFI) {
                     Class myclass = new Class(context,mainactivity reference); //dont know how to get main activity here
                }

            }
        }
    }

Is there is any way that I can get it without Intent or there is some other method. I am in learning phase any help will be appreciated.

In manifest:

<receiver android:name="myreceiver">
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
        </receiver>

score 0 · Answer 1 · answered May 15 '17 at 14:52

0

I dont know how to access main activity in broadcast receiver

You don't. If this is a manifest-registered receiver, you may not have an instance of this activity, anyway.

Either:

Register the receiver from inside the Activity, via registerReceiver(), in which case your nested BroadcastReceiver class can reference the outer Activity instance, or
Use an event bus (greenrobot's EventBus, LocalBroadcastManager, etc.) to publish your event, and have your activity subscribe on that bus (if the activity happens to be around)

answered May 15 '17 at 14:52

CommonsWare

986,068
189
2,389
2,491

I could not understand your first line about registration. I have registered it in manifest see my edited code in the post – exceptionnotgood May 15 '17 at 14:56
@exceptionnotgood: Your process does not live forever. So, the user starts your app from the home screen launcher. The user then leaves your app. Your process is terminated. Then a connectivity change occurs. At this point, you receive the broadcast (at least on older Android devices), but you have no activity. A `BroadcastReceiver` registered in the manifest, as yours is, cannot make *any* assumptions about what activities may or may not exist in the process. – CommonsWare May 15 '17 at 15:03
thank you for you detailed explanation. So what should I do now? – exceptionnotgood May 15 '17 at 15:05

score 0 · Accepted Answer · answered May 15 '17 at 15:11

0

Try this hope it works:
in Main Activity:
public class MainActivity extends Activity {

public static MainActivity getInstance() {
    return new MainActivity();
}
}
And in your receiver:
MainActivity reference=MainActivity.getInstance();

answered May 15 '17 at 15:11

Malika

74
3

The method you proposed will not in my case because in my case I am updating a textview in main activity from "Class" class and it will throw null pointer in that case – exceptionnotgood May 15 '17 at 15:29
then you have to give reference to main activity in on create method after inistialize ui..and use this reference in getInstance(). – Malika May 15 '17 at 15:41
hope it work: static MainActivity ref=null ; @Override protected void onCreate(Bundle savedInstanceState) { setContentView(R.layout.activity_main); //// Initialize ui ref=this; super.onCreate(savedInstanceState); } public static MainActivity getInstance() { return ref; } – Malika May 15 '17 at 16:15
Thank you very much. you solved my problem. Thank you – exceptionnotgood May 15 '17 at 16:55

Accessing main activity in Broadcast Reciever without using intent

2 Answers2

Linked