从片段启动活动

Question

I have an Activity with a single Fragment that asks the user to login. Once the person logs in, a new Activity is launched. My question is, once the the person enters their credentials and hits the login button on the Fragment should

A)the fragment alert its current Activity first and then from there start the new Activity. For example, here is my Fragment:

public class LoginFragment extends Fragment implements View.OnClickListener {
private Button loginButton;
private ClickedInterface clickedInterface;

public LoginFragment() {
    // Required empty public constructor
}

static interface ClickedInterface{
    public void buttonClicked(View v);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_login, container, false);
    loginButton = (Button)view.findViewById(R.id.fragment_login_loginButton);
    loginButton.setOnClickListener(this);
    return view;
}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    this.clickedInterface = (ClickedInterface)activity;
}

@Override
public void onDetach() {
    super.onDetach();
    clickedInterface = null;
}

@Override
public void onClick(View v) {
    switch (v.getId()){
        case R.id.fragment_login_loginButton:{
            clickedInterface.buttonClicked(v);
            break;
        }
    }
}

And Here is the Activity using the ClickedInterface method:

    @Override
public void buttonClicked(View v) {
    switch (v.getId()){
        case R.id.fragment_login_loginButton:{
            //Do Stuff
            break;
        }
    }
}

OR

B)launch the new Activity right from the Fragment?

Thank you

Answer 1

It totally depends on what business logic you have in your fragment, and whether you're using it in multiple activities. For example, you might have a share button, and a button that sends an Intent to rate your app in the Play Store.

In the sharing scenario, you might want each activity to have a different share text. In this case, you would get a reference of the activity, check that it implements an interface, then delegate everything to the activity:

// share scenario (delegate to Activity)

if (getActivity() instanceof MyCallback) {
    ((MyCallback)getActivity()).launchMyIntent(); // TODO handle callback in activity
}

However, if you know for a fact that you only want one behaviour regardless of where you are in the app (like with a rating button), it might make sense to just send your intent straight from the Fragment.

// rating scenario (send intent from fragment

getActivity().startActivity(myIntent);

Answer 2

The best way is to pass the control to MainActivity and then let the activity do the rest.

Second way of doing is--> Create a static method like openPostLoginActivity inside MainActivity and call it from your fragment. This way you can ensure that the global action is always residing in parent. This would mostly help you when you will be having multiple fragments. I have seen this type of approach used by pubnub sample android app

Third is the one which you mentioned. Opening it from fragment itself.

Frankly speaking in your scenario you can use any one of above. It depends whether you want to stuck with the standards or just want your work to get done. All the best!!1