DialogFragment中的ViewPager,IllegalStateException:Fragment没有视图

Question

EDIT3:似乎只有API17及以上才能让ViewPager与ChildFragmentManager一起正常工作.........

我正在尝试添加一个ViewPager我的DialogFragment:

public class FirstLaunchDialogFragment extends DialogFragment {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setStyle(DialogFragment.STYLE_NORMAL, R.style.Theme_Sherlock_Light_Dialog);
}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    final View v = getActivity().getLayoutInflater().inflate(
            R.layout.fragment_dialog_first_launch, null);
    ViewPager viewPager = (ViewPager) v.findViewById(R.id.pager);

    viewPager.setAdapter(new FirstLaunchFragmentsAdapter(getChildFragmentManager()));

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v).setInverseBackgroundForced(true);
    return builder.create();
}
}

由于某些原因,它会崩溃说:

04-06 00:00:49.600: E/AndroidRuntime(3734): java.lang.IllegalStateException: Fragment does not have a view
04-06 00:00:49.600: E/AndroidRuntime(3734):     at android.support.v4.app.Fragment$1.findViewById(Fragment.java:1425)
04-06 00:00:49.600: E/AndroidRuntime(3734):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:901)
04-06 00:00:49.600: E/AndroidRuntime(3734):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
04-06 00:00:49.600: E/AndroidRuntime(3734):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
04-06 00:00:49.600: E/AndroidRuntime(3734):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
04-06 00:00:49.600: E/AndroidRuntime(3734):     at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:461)
.....

现在我一直在谷歌搜索Fragment does not have a view异常半天没有结果

在我看来,适配器不能膨胀布局或东西......

这是我的片段和适配器

public static class UserWelcomeFragment extends Fragment {

    public static UserWelcomeFragment newInstance() {
        return new UserWelcomeFragment();
    }

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

        return v;
    }

}

private class FirstLaunchFragmentsAdapter extends FragmentPagerAdapter {

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

    @Override
    public Fragment getItem(int arg0) {
        switch (arg0) {
        case 0:
            return UserWelcomeFragment.newInstance();

        case 1:
            return new IntegrationSelectingDialogFragment();

        default:
            return UserWelcomeFragment.newInstance();
        }

    }

    @Override
    public int getCount() {
        return 2;
    }

}

编辑:https://code.google.com/p/android/issues/detail？ id = 42601看起来相关

编辑2:我正在测试API 16,该项目正在使用支持库v4修订版12

Answer 1

您正在哪个 Android 版本上进行测试？ViewPager 使用片段，并且由于您的 ViewPager 本身位于片段中，因此您正在嵌套片段。仅 API 17 (Jellybean) 支持嵌套片段，因此此实现仅适用于 Android 4.1+ 的设备。