片段內的ViewPager返回IllegalStateException

Question

我想在片段內使用PagerView創建選項卡，但運行以下代碼將返回IllegalStateException：

源代碼：

public class HomeFragment extends Fragment {

private TabLayout tabs;
private ClassesFragment classesFragment;
private ExamsFragment examsFragment;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    classesFragment = new ClassesFragment();
    examsFragment = new ExamsFragment();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View v = inflater.inflate(R.layout.fragment_main_classes, container, false);
    Toolbar toolbar = getActivity().findViewById(R.id.toolbar);

    ViewPager viewPager = new ViewPager(getContext());
    viewPager.setLayoutParams(new Toolbar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
    setupViewPager(viewPager);
    toolbar.addView(viewPager);

    tabs = new TabLayout(getContext());
    tabs.setLayoutParams(new Toolbar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
    toolbar.addView(tabs);
    tabs.setupWithViewPager(viewPager);
    return v;
}

// Add Fragments to Tabs
private void setupViewPager(ViewPager viewPager) {
    PagerAdapter adapter = new PagerAdapter(getChildFragmentManager());
    adapter.addFragment("Занятия", ExamsFragment.newInstance());
    viewPager.setAdapter(adapter);
}

private class PagerAdapter extends FragmentPagerAdapter {
    private List<Fragment> fragments = new ArrayList<>();
    private List<String> titles = new ArrayList<>();

    public PagerAdapter(FragmentManager fm) {
        super(fm);
        fragments.add(ExamsFragment.newInstance());
        titles.add("new");
    }

    @Override
    public Fragment getItem(int position) {
        return fragments.get(position);
    }

    public void addFragment(String title, Fragment fragment)
    {
        titles.add(title);
        fragments.add(fragment);
    }

    @Override
    public int getCount() {
        return fragments.size();
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return titles.get(position);
    }
}

---

IllegalStateException：

流程：com.company.user.blabla，PID：22256 java.lang.IllegalStateException：帶有適配器com.company.user.blabla.fragments.HomeFragment$PagerAdapter@ca3cef6的ViewPager需要在android.support.v4.app上具有視圖ID。 android.support.v4.view.ViewPager.populate（ViewPager.java:1119）上的FragmentPagerAdapter.startUpdate（FragmentPagerAdapter.java:81）在android.support.v4.view.ViewPager.populate（ViewPager.java:1087） .support.v4.view.ViewPager.onMeasure（ViewPager.java:1613）在android.view.View.measure（View.java:21998）在android.support.v7.widget.Toolbar.measureChildCollapseMargins（Toolbar.java:1547） ）在android.support.v7.widget.Toolbar.onMeasure（Toolbar.java:1655）在android.view.View.measure（View.java:21998）在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:6580）在android.widget.LinearLayout.measureVertical（LinearLayout.java:806）在android.widget.LinearLayout.measureVertical（LinearLayout.java:806）在android.widget.LinearLayout.onMeasure（LinearLayout.java ：685），位於android.support.design.widget.AppBarLayout.onMeasure（AppBarLayout.java:223），位於android.view.View.measure（View.java:21998），位於android.view.ViewGroup.measureChildWithMargins（ViewGroup.java： 6580），位於android.support.design.widget.AppBarLayout $ Behavior.onMeasureChild（AppBarLayout.java:1040），位於android.support.design.widget.CoordinatorLayout.onMeasureChild（CoordinatorLayout.java:713），位於android.support.design.widget .AppBarLayout $ Behavior.onMeasureChild（AppBarLayout.java:770）在android.support.design.widget.CoordinatorLayout.onMeasure（CoordinatorLayout.java:783）在android.view.View.measure（View.java:21998）在android。在android.view.view.ViewGroup.measureChildWithMargins（ViewGroup.java:6580）在android.view.View.measure（View.java:21998）在support.v4.widget.DrawerLayout.onMeasure（DrawerLayout.java:1080） .FrameLayout.onMeasure（FrameLayout.java:185）在android.support.v7.widget.ContentFrameLayout.onMeasure（ContentFrameLayout.java:139）在android.view.View.measure（View.java:2） 1998年）在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:6580）在android.widget.LinearLayout.measureChildBeforeLayout（LinearLayout.java:1514）在android.widget.LinearLayout.measureVertical（LinearLayout.java:806）在android。在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:6580）在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:6580）在android.view.View.measure（View.java:21998）的widget.LinearLayout.onMeasure（LinearLayout.java:685） （FrameLayout.java:185）在android.view.View.measure（View.java:21998）在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:6580）在android.widget.LinearLayout.measureChildBeforeLayout（LinearLayout.java： 1514），位於android.widget.LinearLayout.measureVertical（LinearLayout.java:806），位於android.widget.LinearLayout.onMeasure（LinearLayout.java:685），位於android.view.View.measure（View.java:21998）。 com.android.inter上android.widget.FrameLayout.onMeasure（FrameLayout.java:185）上的view.ViewGroup.measureChildWithMargins（ViewGroup.java:6580） nal.policy.DecorView.onMeasure（DecorView.java:721）在android.view.View.measure（View.java:21998）在android.view.ViewRootImpl.performMeasure（ViewRootImpl.java:2410）在android.view.ViewRootImpl android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:1751）處的.measureHierarchy（ViewRootImpl.java:1498）android.view.ViewRootImpl $ TraversalRunnable處的android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1386） android.view.Choreographer $ CallbackRecord.run（Choreographer.java:911）的ViewRootImpl.java:6733）android.view.Choreographer.doCallbacks（Choreographer.java:723）的android.view.Choreographer.doFrame（Choreographer.java） ：658）在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:897）在android.os.Handler.handleCallback（Handler.java:789）在android.os.Handler.dispatchMessage（Handler.java:98）在android.os.Looper.loop（Looper.java:164）

我在android上沒有太多經驗。 搜索沒有用，或者我搜索不正確。 我該怎么做才能解決這個問題？

Answer 1

您的pagerAdapter流量不正確。

https://guides.codepath.com/android/ViewPager-with-FragmentPagerAdapter

希望這個能對您有所幫助..