把ViewPager 从一个fragment切换到另一个fragment中

Question

Viewpager 中有两个pages，在每一个 fragment中，我放入一个按钮到switching fragment中，但是如果我改变方向，switching不能运行。对于switching fragment，我使用的是 OnChangePageButtonClick 接口。为什么会出现这种情况呢？
ViewPager Activity:

public class ViewPagerMusic extends FragmentActivity implements OnChangePageButtonClick {
    private ViewPager vp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.view_pager_music);
        ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(super.getSupportFragmentManager(), fragments);

        vp = (ViewPager)findViewById(R.id.viewpager);
        vp.setAdapter(viewPagerAdapter);
    }
    private class ViewPagerAdapter extends FragmentStatePagerAdapter {

        public ViewPagerAdapter(FragmentManager fm) {
            super(fm);
        }
        @Override
    public Fragment getItem(int position) {
        switch(position) {
            case 0:
                MainPage mainPage = new MainPage();
                mainPage.setOnChengeButtonListener(ViewPagerMusic.this);
                return mainPage;
            case 1:
                PlaylistPage playlistPage = new PlaylistPage();
                playlistPage.setOnChengeButtonListener(ViewPagerMusic.this);
                return playlistPage;
        }
        return null;
    }
       @Override
        public int getCount() {
            return 2;
        }
    }
    @Override
    public void selectPage(int page) {
        vp.setCurrentItem(page);        
    }
}

Frgamnets:

public class MainPage extends Fragment {
    public MainPage() {
        setRetainInstance(true);
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.music_main_page, container, false);
        ImageButton btnPlaylist = (ImageButton)v.findViewById(R.id.btnGoPlaylist2);
        btnPlaylist.setOnClickListener(onButtonListener);
        return v;
    }
    private OnClickListener onButtonListener = new OnClickListener() {

        @Override
        public void onClick(View view) {
            onChangePageButtonClick.selectPage(1);
        }
    };
    public void setOnBackButtonListener(OnChangePageButtonClick onChangePageButtonClick) {
        this.onChangePageButtonClick = onChangePageButtonClick;
    }
    private OnChangePageButtonClick onChangePageButtonClick;
}

Playlist fragment 与 MainPage fragment相似。

Answer 1

没明白你那switching 的意思，是不能切换fragment ？有没有可能是你的代码有问题? OnChangePageButtonClick 设置那一设置错了item index ?