Can't include a fragment to use in a tabbed activity. Different fragments with FragmentPagerAdapter

Question

I am writing an app using tabbed activity (created with a wizard, Android Studio 1.4.1). I am having troubles trying to put my own fragment for second tab. For the code below, the line (as suggested in [1])

fragment = new ExplanationFragment();

causes following error: Incompatible types. Required: android.support.v4.app.Fragment. Found: ...ExplanationFragment. I tried as well

fragment = ExplanationFragment.newInstance;

with the same result.

public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a PlaceholderFragment (defined as a static inner class below).
//          return PlaceholderFragment.newInstance(position);
            Fragment fragment = null;
            switch (position) {
                case 1:
                    fragment = new ExplanationFragment();
                    break;
                default:
                    fragment = PlaceholderFragment.newInstance(position);
                    break;
            }
            return fragment;
        }

The fragment itself is just created with the wizard:

package ...;

import android.app.Activity;
import android.net.Uri;
import android.os.Bundle;
import android.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;



public class ExplanationFragment extends Fragment {
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";


    private OnFragmentInteractionListener mListener;


    public static ExplanationFragment newInstance(String param1, String param2) {
        ExplanationFragment fragment = new ExplanationFragment();
        Bundle args = new Bundle();
        return fragment;
    }

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

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_explanation_fragment, container, false);
    }

    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mListener = (OnFragmentInteractionListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                                                 + " must implement OnFragmentInteractionListener");
        }
    }

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

    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        public void onFragmentInteraction(Uri uri);
    }

}

I actually expect the solution to lie somewhere completely else (some xml maybe, or particular Fragment class), but can't track it down precisely. Is it at all possible to use several different classes of fragments with a FragmentPagerAdapter?

[1] Android Tabbed Activity: Action Bar Tabs with ViewPager: different layout for each tab

in `ExplanationFragment` you should import `v4.app.Fragment` — Blackbelt, Nov 07 '15 at 19:36
just try changing this line in your fragment `import android.app.Fragment;` to import `android.support.v4.app.Fragment` — Bhargav, Nov 07 '15 at 19:36

score 0 · Answer 1 · answered Nov 07 '15 at 19:37

0

just try changing this line in your fragment import android.app.Fragment; to import android.support.v4.app.Fragment

answered Nov 07 '15 at 19:37

Bhargav

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yeah, realised it just before a while. That did the job. Thanks anyway (: – Antek Nov 07 '15 at 19:39

score 0 · Accepted Answer · answered Nov 07 '15 at 19:39

causes following error: Incompatible types. Required: android.support.v4.app.Fragment. Found: ...ExplanationFragment

That tells you that you are inheriting from the wrong class.

There are two implementations of fragments: the one built into Android as of API Level 11, and the one from the Android support library. You are welcome to use either of those, but you have to be consistent, at least within one activity (though I would recommend being consistent throughout the whole app). What you cannot do is mix and match fragment implementations.

SectionsPagerAdapter is inheriting from android.support.v4.app.FragmentPagerAdapter. It is using the fragment backport.

ExplanationFragment is inheriting from android.app.Fragment. It is using the native fragments. Hence, you are not being consistent.

Assuming that your ViewPager was working with just the one tab before, the simplest answer is to have ExplanationFragment inherit from android.support.v4.app.Fragment, so you consistently are using the fragment backport.

Can't include a fragment to use in a tabbed activity. Different fragments with FragmentPagerAdapter

2 Answers2