Communicating between a fragment and an activity - best practices

Question

This question is mostly to solicit opinions on the best way to handle my app. I have three fragments being handled by one activity. Fragment A has one clickable element th

Answer 1

I made a annotation library that can do the cast for you. check this out. https://github.com/zeroarst/callbackfragment/

@CallbackFragment
public class MyFragment extends Fragment {

    @Callback
    interface FragmentCallback {
       void onClickButton(MyFragment fragment);
    }    
    private FragmentCallback mCallback;

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.bt1
                mCallback.onClickButton(this);
                break;
            case R.id.bt2
                // Because we give mandatory = false so this might be null if not implemented by the host.
                if (mCallbackNotForce != null)
                mCallbackNotForce.onClickButton(this);
                break;
        }
    }
}

It then generates a subclass of your fragment. And just add it to FragmentManager.

public class MainActivity extends AppCompatActivity implements MyFragment.FragmentCallback {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        getSupportFragmentManager().beginTransaction()
            .add(R.id.lo_fragm_container, MyFragmentCallbackable.create(), "MY_FRAGM")
            .commit();
    }

    Toast mToast;

    @Override
    public void onClickButton(MyFragment fragment) {
        if (mToast != null)
            mToast.cancel();
        mToast = Toast.makeText(this, "Callback from " + fragment.getTag(), Toast.LENGTH_SHORT);
        mToast.show();
    }
}