Tab+ViewPager 未更新而是显示奇怪的警告 expected state 3 found 2

Question

我有一个主要活动，其中包括一个带 ViewPager 的 TabLayout

我添加了 3 个选项卡，每个选项卡都有单独的片段，其中包含一个 recyclerview，并且这些 recyclerviews 有一个复选框，每当我滑动 viewpager（我保存选中共享偏好中的位置并通过共享偏好更新）。

我的问题是每当我选中 tab1 中的复选框时，tab2 都不是 updating/refreshing，直到我向下滚动 Recyclerview。 tab3 工作正常。 我也在 logcat 中收到一个奇怪的警告。

 03-05 09:35:53.345 4317-4327/com.example.rubin W/art: Suspending all threads took: 6.805ms
    03-05 09:35:58.310 4317-4317/com.example.rubin W/FragmentManager: moveToState: Fragment state for Tab3{10a5f1f0 #2 id=0x7f0d00b6} not updated inline; expected state 3 found 2
    03-05 09:36:01.363 4317-4317/com.example.rubin W/FragmentManager: moveToState: Fragment state for Tab1{2d9aa887 #1 id=0x7f0d00b6} not updated inline; expected state 3 found 2

我的 PagerAdapter

public class PagerAdapter1 extends FragmentStatePagerAdapter {
    int mNumOfTabs;
    public PagerAdapter1(FragmentManager fm, int NumOfTabs) {
        super(fm);
        this.mNumOfTabs = NumOfTabs;
    }
    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
               return new Tab1();
            case 1:
               return new Tab2();
            case 2:
               return new Tab3();

            default:
                return null;

        }
    }

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

Tablayout OnPageChangelistener

final PagerAdapter1 adapter = new PagerAdapter1
                (getSupportFragmentManager(), tabLayout1.getTabCount(), getApplicationContext());
        viewPager1.setAdapter(adapter);
        viewPager1.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout1));
        tabLayout1.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager1.setCurrentItem(tab.getPosition());
                adapter.notifyDataSetChanged();
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {
            }
        });
    }

每个片段的代码。

 public class Tab1 extends Fragment {

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            View v = inflater.inflate(R.layout.home_tab1_recycler, container, false);
            RecyclerView rv = (RecyclerView) v.findViewById(R.id.home_recyclerview);   
            LinearLayoutManager llm = new LinearLayoutManager(getContext());
            rv.setLayoutManager(llm);
            rv.setHasFixedSize(true); // to improve performance
            rv.setAdapter(new HomeManager()); // the projectdatabase manager is assigner to the RV
            return v;
        }

        public class HomeManager extends RecyclerView.Adapter<HomeManager.RecyclerViewHolder> {
    int Length,h;
 View v1;
        ArrayList<String> PROJECT_ID = new ArrayList<String>();
Set<String> set;
        List<String> selected;
     public class RecyclerViewHolder extends RecyclerView.ViewHolder {
     CheckBox mCheck;
      RecyclerViewHolder(final View itemView) {
                    super(itemView);
      mCheck = (CheckBox) itemView.findViewById(R.id.PROJECT_fav);
     SharedPreferences pref = getContext().getSharedPreferences("MirSP", Context.MODE_PRIVATE);
                    set = pref.getStringSet("FAV", null);
      if (set != null) {
                        selected = new ArrayList<String>(set);
                    } else {
                        selected = new ArrayList<String>();
                    }
    mCheck.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
     h = getAdapterPosition();
    check = PROJECT_ID.get(h); // for saving the project id from json.
     if (selected.contains(check)) {
                                    selected.remove(check);
                                    mCheck.setBackgroundResource(R.drawable.ic_favorite_white1_24dp);
                                    Snackbar snackbar = Snackbar.make(v, "Property Unfavorited", Snackbar.LENGTH_SHORT);
                                    snackbar.show();
                                } else {
                                    selected.add(check);
                                    mCheck.setBackgroundResource(R.drawable.ic_favorite_white_24dp);
                                    Snackbar snackbar = Snackbar.make(v, "Property Favorited", Snackbar.LENGTH_SHORT);
                                    snackbar.show();

                                }
                                Log.e("HF update checked", String.valueOf(selected));
                                Set<String> set = new HashSet<String>();
                                set.addAll(selected);
                                SharedPreferences pref = getContext().getSharedPreferences("MirSP", Context.MODE_PRIVATE);
                                SharedPreferences.Editor editor = pref.edit();
                                editor.putStringSet("FAV", set);
                                editor.commit();
                            }
         }
                    });
     @Override
            public RecyclerViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
                v1 = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.recyclerview_item, viewGroup, false);
                return new RecyclerViewHolder(v1);
            }

            @Override
            public void onBindViewHolder(final RecyclerViewHolder viewHolder, int i) {
    SharedPreferences pref = getContext().getSharedPreferences("MirSP", Context.MODE_PRIVATE);
                set = pref.getStringSet("FAV", null);
                if (set != null) {
                    selected = new ArrayList<String>(set);
                } else {
                    selected = new ArrayList<String>();
                }
                Log.e("HF update UI", String.valueOf(selected));
    if (String.valueOf(selected).contains(String.valueOf(PROJECT_ID.get(i)))) {
                        viewHolder.mCheck.setBackgroundResource(R.drawable.ic_favorite_white_24dp);
                    } else {
                        viewHolder.mCheck.setBackgroundResource(R.drawable.ic_favorite_white1_24dp);
                    }
                }
     @Override
            public int getItemCount() {
                //Code for Total length of json
                return Length;
            }

Answer 1

FragmentPagerAdapter 调用 setUserVisibleHint(true|false) 在活动片段的邻域上，这会改变该片段的状态。这至少是 "weird warning messages" 的答案，但它可能无法解决您的问题。

关于您关于如何解决该警告消息的评论，我创建了自己的 FragmentPagerAdapter，如下所示：

public abstract class AbstractTabPagerAdapter extends PagerAdapter {

    private static final String TAG = AbstractTabPagerAdapter.class.getCanonicalName();

    private final FragmentManager mFragmentManager;

    private FragmentTransaction mCurTransaction;

    private Fragment mCurrentPrimaryItem = null;

    public AbstractTabPagerAdapter(FragmentManager fragmentManager) {
        mFragmentManager = fragmentManager;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        if (mCurTransaction == null) {
            throw new IllegalArgumentException("current transaction must not be null");
        }
        String fragmentTag = makeFragmentName(container.getId(), position);
        Fragment fragment = (Fragment) mFragmentManager.findFragmentByTag(fragmentTag);
        if (fragment != null) {
            mCurTransaction.attach(fragment);
            Log.d(TAG, "Attaching existing fragment " + fragment + " at position " + position);
            //mCurTransaction.add(container.getId(), fragment, makeFragmentName(container.getId(), position));
        } else {
            fragment = getItem(position);
            mCurTransaction.add(container.getId(), fragment, fragmentTag);
            Log.d(TAG, "Attaching new fragment " + fragment + " at position " + position);
        }

        if (fragment != mCurrentPrimaryItem) {
            fragment.setMenuVisibility(false);
            //fragment.setUserVisibleHint(false);
        }

        return fragment;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        if (mCurTransaction == null) {
            throw new IllegalArgumentException("current transaction must not be null");
        }
        mCurTransaction.detach((Fragment) object);
        //mCurTransaction.remove((Fragment)object);
    }

    @Override
    public void setPrimaryItem(ViewGroup container, int position, Object object) {
        //super.setPrimaryItem(container, position, object);
        Fragment fragment = (Fragment) object;
        if (fragment != mCurrentPrimaryItem) {
            Log.d(TAG, "set Primary item " + position + " to " + fragment);
            if (mCurrentPrimaryItem != null) {
                mCurrentPrimaryItem.setMenuVisibility(false);
                // this command unexpectedly changes the state of the fragment which leads to a warning message and possible some strange behaviour
                //mCurrentPrimaryItem.setUserVisibleHint(false);
            }
            if (fragment != null) {
                fragment.setMenuVisibility(true);
                //fragment.setUserVisibleHint(true);
            }
            mCurrentPrimaryItem = fragment;
        }
    }

    @Override
    public boolean isViewFromObject(View view, Object fragment) {
        return ((Fragment) fragment).getView() == view;
    }

    public abstract Fragment getItem(int position);

    @Override
    public void startUpdate(ViewGroup container) {
        super.startUpdate(container);
        if (mCurTransaction != null) {
            throw new IllegalArgumentException("current transaction must not be null");
        }
        mCurTransaction = mFragmentManager.beginTransaction();
        Log.d(TAG, "FragmentTransaction started");
    }

    @Override
    public void finishUpdate(ViewGroup container) {
        if (mCurTransaction != null) {
            mCurTransaction.commit();
            mCurTransaction = null;
            //mFragmentManager.executePendingTransactions();
            Log.d(TAG, "FragmentTransaction committed");
        } else {
            throw new IllegalArgumentException("current transaction must not be null");
        }
    }

    private String makeFragmentName(int viewId, int position) {
        if (viewId <= 0)
            throw new IllegalArgumentException("viewId " + viewId);
        return "tabpageradptr:" + getPageTitle(position) + ":" + viewId + ":" + position;
    }

}

警告消息现在消失了，目前我没有遇到任何缺陷 - 但我仍在研究中。

Answer 2

不重要。这只是一个警告。请尝试将 ViewPager 布局的背景更改为空（不设置背景）。

Answer 3

这个问题我花了很多时间。问题是您尝试在 OnPageChangeListener 侦听器中更新 viewpager，它会抛出警告

not update in line

解决方案：

所有数据更改和更新视图都应调用 OnPageChangeListener，例如：片段的 onCreateView

我的警告消失了！ viewpager 更新完全

Answer 4

已经晚了，但我想出了使用 FragmentPagerAdapter 的最佳方法，虽然它没有消除警告，但它解决了目的，如果有人能告诉我该警告的实际含义以及实际导致警告的原因，它会符合我的最大利益。

首先在viewpager创建方法中使用的所有片段如下。

public void updateView() {
  //Update whatever views or data you want to update
}

同时覆盖 FragmentPagerAdapter 中使用的方法 setUserVisibleHint 以通知用户片段是否可见。

 @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        this.isVisibleToUser = isVisibleToUser;
        super.setUserVisibleHint(isVisibleToUser);
    }

最后在您的片段中添加以下代码以在片段可见时更新 view/date。

@Override
    public void onStart() {
            if (isVisibleToUser)
                updateView();
    }

然后在您的 TabFragment 或 Activity

中实现它

viewpager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {

                switch (position) {
                    case 0: {
                         ((Fragment) mFragmentList.get(0)).updateView();
                        break;
                    }
                    case 1: {
                         ((Fragment) mFragmentList.get(1)).updateView();
                        break;
                    }
                }
            }

这将负责持续更新数据，无论是滑动还是单击选项卡，如果有人发现任何问题或错误，请发表评论并让我知道或随时编辑解决方案

并且我投票赞成上面的解决方案，它为我提供了应用此解决方案的方法。谢谢@mikes

Answer 5

"W/FragmentManager: moveToState: … expected state 3 found 2" 警告可以忽略并已在支持库 v24.0.0 中删除。

引用官方开发者answer:

You don't need to do anything additional; this is an informational log message only. […]

The log itself as described here does not affect behavior. Please open a new bug if you are having other issues; conflating different issues in the same bug makes those separate issues more difficult to track.

Closing comments as the log issue has been resolved for a future release.

Answer 6

在视图寻呼机中同时加载相邻的标签。因此，您在选项卡 1 中的操作不会反映在选项卡 2 中，因为它已经加载。您应该使用广播接收器来解决这个问题。在选项卡 1 中广播事件并在选项卡 2 中接收事件

Tab+ViewPager 未更新而是显示奇怪的警告 expected state 3 found 2

Tab+ViewPager not updating instead shows weird warning expected state 3 found 2

android

android-fragments

android-viewpager

android-tabs