将片段链接到活动错误

Question

Im trying to attach a fragment to an activity, I've followed multiple tutorials and my code seems exactly the same (adapted to my app) than the ones in the tutorials and I cant find where my error is.

  import android.os.Bundle;
  import android.support.design.widget.FloatingActionButton;
  import android.support.design.widget.Snackbar;
  import android.content.Intent;
  import android.support.v4.app.FragmentActivity;
  import android.view.View;


protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_comments);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.id_layout_comments, new CommentsFragment())
                .commit();
    }

I get the error at the ".add(R.id.id_layout_comments, new CommentsFragment())" and it says: "cant resolve method add(int, package.CommentsFragment)".

This is the header of the class where I want to invoke the fragment:

 public class CommentsActivity extends FragmentActivity 

And this is the one of the fragment itself:

 public class CommentsFragment extends Fragment

If you need any more information, let me know. Thanks a lot in advanced!

Answer 1

Really you didn't need to extend FragmentActivity, just extend Activity is enough.

Look at this example:

CommentsActivity:

public class CommentsActivity extends FragmentActivity {
...
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_comments);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.id_layout_comments, new CommentsFragment())
                .commit();
    }
...
}

CommentsFragment:

public class CommentsFragment extends Fragment{
...
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.your_resource, container, false);
    return view;
}
...
}

That's it :D