Android RecyclerView.ViewHolder.itemView getWidth（）getHeight（）返回0

我试图在RecyclerView中列出一行图像

下面是一些代码

Java

public class ItemSelectFragment extends Fragment {

  private ArrayList<Item> mItems;
  private RecyclerView mRecyclerView;
  public  ItemAdapter mAdapter;
  private String TAG ="Item_Select_Fragment";


@Override
  public void onCreate(@Nullable Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setRetainInstance(true);
    mItems=new ArrayList<>();
    for(int i=1;i<9;i++) {
        assert mItems != null;
        mItems.add(new Item(i));
    }
    mAdapter = new ItemAdapter();
  }


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

    View view = inflater.inflate(R.layout.item_select_fragment, container, false);
    mRecyclerView = view.findViewById(R.id.item_select_recycler_view);
    mRecyclerView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            Log.d(TAG,"Recycler View Width: "+ mRecyclerView.getWidth()+" Height: "+ mRecyclerView.getHeight());
            LinearLayoutManager manager=new LinearLayoutManager(getActivity(), LinearLayoutManager.HORIZONTAL,false);

            mRecyclerView.setLayoutManager(manager);
            mRecyclerView.setAdapter(mAdapter);
            mRecyclerView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
        }
    });
    return view;
}


private class ItemHolder extends RecyclerView.ViewHolder {
    private ItemBinding itemBinding;

    private ItemHolder(ItemBinding binding) {
        super(binding.getRoot());
        itemBinding = binding;
        itemBinding.setItemViewModel(new ItemViewModel(itemBinding.getRoot(),getContext()));
    }

    public void bind(Item item) {
        itemBinding.getItemViewModel().setItem(item);
        itemBinding.executePendingBindings();
    }

}

public class ItemAdapter extends RecyclerView.Adapter<ItemHolder> {


    public ItemAdapter(){}

    @Override
    public ItemHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater      = LayoutInflater.from(getActivity());
        ItemBinding binding = DataBindingUtil.inflate(inflater, R.layout.item, parent, false);
        return new ItemHolder(binding);
    }

    @Override
    public void onBindViewHolder(ItemHolder holder, int position) {
        Log.d(TAG,"Binding Position: "+position);
            Item item = mItems.get(position);
            holder.bind(item);

    }

    @Override
    public int getItemCount() {
        return mItems.size();
    }

    public void resetAdapter(){this.notifyDataSetChanged();}
}

  @Override
  public void onResume(){
    super.onResume();
    mAdapter.resetAdapter();
  }
  @Override
  public void onDestroy(){
    super.onDestroy();

  }
}

item.xml

<?xml version="1.0" encoding="utf-8"?>
<layout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto">
  <data>
    <variable
        name="ItemViewModel"
        type="com.example.mytestapplication.ItemViewModel" />
  </data>
<android.support.constraint.ConstraintLayout
android:layout_width="120dp"
android:layout_height="100dp">


<ImageButton

    android:id="@+id/imageButton"
    android:layout_width="match_parent"
    android:layout_height="80dp"
    android:scaleType="centerInside"
    app:layout_constraintBottom_toTopOf="@+id/textView"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    android:src="@{ItemViewModel.thumbnail}" />

<TextView
    android:id="@+id/textView"
    android:layout_width="match_parent"
    android:layout_height="20dp"
    android:text="@{ItemViewModel.title}"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@id/imageButton" />

</android.support.constraint.ConstraintLayout>
</layout>

如您所见，按钮7和8处的视图模型没有展开，宽度和高度为0，这导致了问题

---

有人知道如何解决这个问题吗？

您找到解决方案了吗？我也在想同样的问题。我想我有过，但记不得你找到了解决办法吗？我也在想同样的事情。我想我有过，但记不得了

<?xml version="1.0" encoding="utf-8"?>
<layout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto">
  <data>
    <variable
        name="ItemViewModel"
        type="com.example.mytestapplication.ItemViewModel" />
  </data>
<android.support.constraint.ConstraintLayout
android:layout_width="120dp"
android:layout_height="100dp">


<ImageButton

    android:id="@+id/imageButton"
    android:layout_width="match_parent"
    android:layout_height="80dp"
    android:scaleType="centerInside"
    app:layout_constraintBottom_toTopOf="@+id/textView"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    android:src="@{ItemViewModel.thumbnail}" />

<TextView
    android:id="@+id/textView"
    android:layout_width="match_parent"
    android:layout_height="20dp"
    android:text="@{ItemViewModel.title}"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@id/imageButton" />

</android.support.constraint.ConstraintLayout>
</layout>

D/Item_View_Model: The Image Button Tile is  Image Button 5
D/Item_View_Model: Getting Thumbnail
D/Item_View_Model: The Image File Path is  /storage/emulated/0/DCIM/Icons/5.jpg
D/Item_View_Model: View Model Width :240 Height :200
D/Item_View_Model: The Image Button Tile is  Image Button 6
D/Item_View_Model: Getting Thumbnail
D/Item_View_Model: The Image File Path is  /storage/emulated/0/DCIM/Icons/6.jpg
D/Item_View_Model: View Model Width :240 Height :200
D/Item_Select_Fragment: Binding Position: 6
D/Item_View_Model: The Image Button Tile is  Image Button 7
D/Item_View_Model: Getting Thumbnail
D/Item_View_Model: The Image File Path is  /storage/emulated/0/DCIM/Icons/7.jpg
D/Item_View_Model: View Model Width :0 Height :0
D/Item_Select_Fragment: Binding Position: 7
D/Item_View_Model: The Image Button Tile is  Image Button 8
D/Item_View_Model: Getting Thumbnail
D/Item_View_Model: The Image File Path is  /storage/emulated/0/DCIM/Icons/8.jpg
D/Item_View_Model: View Model Width :0 Height :0