How can I access localised strings from within a static FragmentPagerAdapter

Question

I have followed official documentation on how to implement swipe views with TabStrip instead of Tabs in order to create a Fragment (FragmentMyAccount.class) that contains Nested Fragments (FragmentMyProfile.class and FragmentMyLibrary.class). These nested fragments correspond to the two tabs managed by a childFragmentManager.

The two tabs and astuetz's pagerSlidingTabStrip work fine, but adapter's getPageTitle method doesn't have access to String resources and can only return a hardcoded string for each tab title (see on the bottom of the code). The compile-time error that appears when I try to access the xml resources reads:

"FragmentMyAccount.this cannot be referenced from a static context"

If the code below is not possible to tweak, what alternative implementation would be adequate to achieve my goal?

package com.kouretinho.myapp;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.astuetz.PagerSlidingTabStrip;


public class FragmentMyAccount extends Fragment {

private static final int NUM_ITEMS = 2;

MyAccountAdapter mAdapter;
ViewPager mPager;
PagerSlidingTabStrip mTabStrip;

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

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_my_account, container, false);

    // Initialize the FragmentPager Adapter
    mAdapter = new MyAccountAdapter(getChildFragmentManager());

    // Initialize the ViewPager and set an adapter
    mPager = (ViewPager) rootView.findViewById(R.id.viewpager_my_account);
    mPager.setAdapter(mAdapter);

    // Initialize the TabStrip and bind the tabs to the ViewPager
    mTabStrip = (PagerSlidingTabStrip) rootView.findViewById(R.id.viewpager_tab_strip);
    mTabStrip.setViewPager(mPager);

    return rootView;
}

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

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
}

public static class MyAccountAdapter extends FragmentPagerAdapter{

    private static final int MY_PROFILE = 0;
    private static final int MY_LIBRARY = 1;
    private static final String sExceptionMessage = "FragmentPagerAdapter was asked to getItem " +
            "with position other than 0 or 1. This FragmentPagerAdapter can only return one of" +
            "two Fragments at position 0 or 1.";

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

    @Override
    public int getCount() {
        return FragmentMyAccount.NUM_ITEMS;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position){
            case MY_PROFILE:
                return new UserProfileFragment();
            case MY_LIBRARY:
                return new UserBooksFragment();
            default:
                throw new IllegalStateException(sExceptionMessage);
        }
    }

    @Override
    public CharSequence getPageTitle(int position) {

        switch (position){
            case MY_PROFILE:
// **********  THIS LINE IS PROBLEMATIC, cannot get Localised String resources
               return  FragmentMyAccount.this.getActivity().getResources().getString(R.id.my_profile);
            case MY_LIBRARY:
                return "my_library";
            default:
                return "no_title";
        }
    }
}

}

Ayzen · Accepted Answer · 2014-09-20T19:03:59.507

1

In your case you have to replace:

public static class MyAccountAdapter extends FragmentPagerAdapter

with

public class MyAccountAdapter extends FragmentPagerAdapter

Another way to fix this is to pass Context to MyAccountAdapter in constructor (like you do with FragmentManager).

edited Sep 20 '14 at 19:03

answered Sep 20 '14 at 18:57

Ayzen

933
7
10

Wow, so simple and so correct! I removed the static keyword and it worked great. I still don't understand though, why the documentation proposes a "public static class" vs a plain "public class" – kouretinho Sep 20 '14 at 19:33
1

Maybe they simply don't need to access instance methods or fields of a parent class... – Ayzen Sep 20 '14 at 19:37

How can I access localised strings from within a static FragmentPagerAdapter

1 Answers1