android - 将新适配器分配给我的 ViewPager 时应用程序崩溃

Question

我有一个 ViewPager，它在应用程序启动时由 FragmentStatePagerAdapter 填充:

    ViewPager mViewPager;

    ...

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) 
    {
        super.onViewCreated(view, savedInstanceState);

        mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
        mViewPager.setAdapter(new PageAdapter(getChildFragmentManager()));
        //PageAdapter extends from FragmentStatePagerAdapter
    }

这可以正常工作。

现在，当用户更改应用程序的设置时，我想像这样为 ViewPager 分配一个新的适配器:

@Override
public void updateObserver(SETTING_KEY key) 
{
    mViewPager.setAdapter(new PageAdapter(getChildFragmentManager()));
    Log.d("info", "updating");
}

不幸的是，应用程序在调用 updateObserver 后崩溃，出现以下异常:

01-22 23:22:45.957: E/AndroidRuntime(13131): FATAL EXCEPTION: main 01-22 23:22:45.957: E/AndroidRuntime(13131): java.lang.IllegalStateException: Fragement no longer exists for key f0: index 0 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.support.v4.app.FragmentManagerImpl.getFragment(FragmentManager.java:575) 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.support.v4.app.FragmentStatePagerAdapter.restoreState(FragmentStatePagerAdapter.java:211) 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.support.v4.view.ViewPager.onRestoreInstanceState(ViewPager.java:1281) 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.view.View.dispatchRestoreInstanceState(View.java:13188) 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2850) 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2856) 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.view.View.restoreHierarchyState(View.java:13166) 01-22 23:22:45.957: E/AndroidRuntime(13131): at android.support.v4.app.Fragment.restoreViewState(Fragment.java:425) ...

如何在不使应用程序崩溃的情况下将新适配器分配给 ViewPager？

Answer 1

使用 getFragmentManager() 而不是 getChildFragmentManager()。