Question

When I set a time,how to start an activity or do some actions like button click actions(not toast) at that specific time using broadcast receiver??

Answer 1

You might need AlarmManager + Service to do that.
you can look it here

http://android-er.blogspot.com/2010/10/simple-example-of-alarm-service-using.html

and in Service class (in the link) that display Toast,
just make some new intent and startActivity(intent) there
PS. before start. It’s important that you must add this line also

youintent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

like this

public class AlarmService extends Service {

private Intent alarmIntent;

@Override
public void onCreate() {
    alarmIntent = new Intent(this, AlarmActivity.class);
    alarmIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
}

@Override
public void onStart(Intent intent, int startId) {
    super.onStart(intent, startId);

    //Toast.makeText(this, "MyAlarmService.onStart()", Toast.LENGTH_LONG)
    //      .show();

    startActivity(alarmIntent);
}

// another implement method......
}