How to update the UI of Activity from BroadCastReceiver

Question

I am learning Android concepts Activity and BroadCastReceiver. I want to update the content of Activity from the Br

Answer 1

Squonk-s answer only works, if the Activity is active currently. If you dont want to declare / define your BroadcastReceiver (BR) in an other Activity, or if you want to make some changes even if the app is not foreground, than your solution would look something like this.

First, you declare the BR, and save, or override the data needed to show in Acitvity.

public class MyBR extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // override the data. Eg: save to SharedPref
    }
}

Then in Activity, you show the data

TextView tv = findViewById(R.id.tv);
tv.setText(/*get the data Eg: from SharedPref*/);

And you should use a Timer to refresh the tv as well:

    Timer timer = new Timer();
    timer.schedule(new TimerTask() {
        @Override
        public void run() {
            runOnUiThread(new Runnable() {
                @Override
                 public void run() {
                    TextView tv = findViewById(R.id.tv);
                    tv.setText(/*get the data Eg: from SharedPref*/);
                }
            });
        }
    }, REFRESH_RATE, REFRESH_RATE);

REFRESH_RATE could be something like 1 second, but you decide.