How to pass data from current fragment to previous fragment

This method is also called the Delegate Pattern

• Create an interface with one method like this one:

public interface FragmentCallback {
    void onDataSent(String yourData);
}

• Implement this interface in your FragmentA and implement onDataSent() method:

public class FragmentA implements FragmentCallback {

    @Override
    void onDataSent(String yourData){
        //Do something with your data
    }
}

• Declare this interface variable in Fragment B and create a public setter method:

public class FragmentB {

private FragmentCallback fragmentCallback;

    public void setFragmentCallback(FragmentCallback callback) {
        this.fragmentCallback = callback;
    }
}

• Somewhere withing FragmentA set it as a callback on FragmentB instance:

fragmentB.setFragmentCallback(this);

• Path data from FragmentB to FragmentA (you can do it from one of fragment's lifecycle method if data should be sent when FragmentB is about to be closed):

public class FragmentB {

    public void onDestroy() {
        if(fragmentCallback != null){
            fragmentCallback.onDataSent("Some data from FragmentB");
        }
        super.onDestroy();
    }
}