Call method in fragment from another fragment/activity

Question

I made swipe PageView with fragment like that http://www.androidhive.info/2013/10/android-tab-layout-with-swipeable-views-1/

Fragment2 have function myUpdate() which updates some data in Fragment2 (data from sql to list). I could call it easely in Fragment2, but I also need to run myUpdate() from Fragment1 or from other Activity and i don't know how.

I found a few ways but then need R.id. * or tag and i have no idea where to find it.

  FragmentManager fm = getFragmentManager();
  Fragment2 fragment = (Fragment2) fm.findFragmentByTag(<...>);
  fragment.myUpdate();

or same with findViewById ... I suppose I should make some changes in xml, but i don't know what to change... Thanks.

Answer 1

There are multiple ways to achieve this, one would be local broadcasts. Implementing a BroadcastReceiver for local broadcasts is exactly the same as for normal broadcasts:

private BroadcastReceiver receiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {

        String action = intent.getAction();
        if(action != null && action.equals("update")) {
            // perform your update
        }

    }
};

You can register a BroadcastReceiver for your local broadcasts in the first Fragment like this:

LocalBroadcastManager broadcastManager = LocalBroadcastManager.getInstance(context);

IntentFilter intentFilter = new IntentFilter("update");
// Here you can add additional actions which then would be received by the BroadcastReceiver

broadcastManager.registerReceiver(receiver, intentFilter);

and you can send local broadcasts like this:

Intent intent = new Intent("update");

LocalBroadcastManager broadcastManager = LocalBroadcastManager.getInstance(context);
broadcastManager.sendBroadcast(intent);