Call fragment method inside an activity from another activity

Question

I have an Activity A with a Fragment and an Activity B.

When I click a button inside the Fragment, the Activity B is starting and i assume that the Activity A is onPause.

What I want to do is to click on a button inside the Activity B which will finish() this Activity and then go back to the Activity A.

Doing so would automatically call a method inside the fragment. After research I tried to implements Interface and Fragment transactions but I always get null objects.

How can I make my activities communicating and pass the information to the fragment in this configuration?

score 1 · Accepted Answer · answered Dec 27 '19 at 10:29

Call ActivityB from FragmentA (which is part of ActivityA) as startActivityForResult() instead of startActivity() call.

Using this, you would be able to pass back result from Activity B to Fragment A.

Fragment A (Part of ActivityA) :

// Calling Activity B
Intent intent = new Intent(this, ActivityB.class); 
intent.putExtras(b);    
startActivityForResult(intent, ANY_ID);

// Overriding callback for result
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == ANY_ID && resultCode == Activity.RESULT_OK) {
        // Your logic of receiving data from Activity B
    }
}

Important Point : The Fragment A is the one making the startActivityForResult() call, but it is part of Activity A so Activity A gets the first shot at handling the result. It has to call super.onActivityResult() so that the callback can come to Fragment A

In Activity A :

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    // This is required, in order to get onActivityResult callback in Fragment A
}

Setting result back from Activity B :

Intent resultIntent = new Intent();
// You can pass any data via this intent's bundle by putting as key-value pair
resultIntent.putExtra("Key", Value);
setResult(Activity.RESULT_OK, resultIntent);
finish();

Reference :

Call fragment method inside an activity from another activity

1 Answers1