Question

名为NewsCenterFragment的片段将替换DrawerActivity中的FramLayout。问题是当我将viewPager滑动到下一张幻灯片时，程序将崩溃。给出的异常如下：java.lang.IllegalStateException：指定的子节点已经有父节点。您必须首先在子节点的父节点上调用removeView（）。

public class DrawerActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener,Serializable {
private FragmentManager fm;
private NavigationView navigationView;
private NewsMenu data;
private RadioGroup radioGroup;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_drawer);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    radioGroup = (RadioGroup) findViewById(R.id.content_drawer_radioGroup);
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
    checkCacheForNewsCenterSlideBar();
    changeNewsSlideBar();
    Fragment homeFragment = new HomeFragment();
    fm = getFragmentManager();
    fm.beginTransaction().replace(R.id.content_drawer_content,homeFragment).commit();
    getSupportActionBar().setTitle("Home page");
    radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            switch (checkedId){

                case R.id.content_drawer_radioGroup_shouye:
                    Fragment homeFragment = new HomeFragment();
                    fm.beginTransaction().replace(R.id.content_drawer_content,homeFragment).commit();
                    getSupportActionBar().setTitle("Home page");
                    break;
                case R.id.content_drawer_radioGroup_newscenter:

                    Fragment newsCenterFragment = new NewsCenterFragment(findNewsTabTitle(),DrawerActivity.this);
                    fm.beginTransaction().replace(R.id.content_drawer_content,newsCenterFragment).commit();
                    getSupportActionBar().setTitle("News center");
                    break;
                case R.id.content_drawer_radioGroup_smartservice:

                    break;
                case R.id.content_drawer_radioGroup_goveraffairs:

                    break;
                case R.id.content_drawer_radioGroup_setting:

                    break;
            }
        }
    });
}

public class NewsCenterFragment extends Fragment {
private ViewPager viewPager;
private Activity mActivity;
private ArrayList<String> title;
private ArrayList<View> views;

public NewsCenterFragment(ArrayList<String> title, Activity activity){
    this.title = title;
    this.mActivity = activity;
}


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

    LayoutInflater inflater = (LayoutInflater) mActivity.getSystemService(mActivity.LAYOUT_INFLATER_SERVICE);
    View view = inflater.inflate(R.layout.fragment_newscenter_layout,container,false);

    viewPager = (ViewPager) view.findViewById(R.id.fragment_newscenter_viewPager);
    views = new ArrayList<View>();
    View tempLayout = inflater.inflate(R.layout.news_title_layout,container,false);


    for(int i=0;i<title.size();i++){
        views.add(tempLayout);
    }
    viewPager.setAdapter(new NewsMenuDetailAdapter());
    return view;
}
class NewsMenuDetailAdapter extends PagerAdapter{

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

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view==(LinearLayout)object;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {


        String tabTitle = title.get(position);
               View view = views.get(position);
                TextView textView = (TextView) view.findViewById(R.id.news_title_layout_title);
                textView.setText(tabTitle);
       container.addView(view);
        return view;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((LinearLayout)object);
    }

}

}

java.lang.IllegalStateException：指定的子级已有父级。您必须先在孩子的父母身上调用removeView（）。

我一直在寻找解决方案几个小时。请帮帮我。谢谢。

Answer 1

看起来你的views array中的一个对象有N个引用，从这里开始：

View tempLayout = inflater.inflate(R.layout.news_title_layout,container,false);

for(int i=0;i<title.size();i++){
    views.add(tempLayout);
}

因此，当您的适配器开始返回项目时，它首次成功附加了此视图（tempLayout），但在第二次失败时，因为tempLayout (i.e. views[i])已经拥有上一次调用的父项{{1 }}

您应该提供另一个虚增的视图，或在致电instantiateItem

之前致电((ViewGroup)child.getParent()).removeView(child)

ViewPager无法删除片段

1 个答案: