更新到API 27后，RecyclerView Adapter遇到困难

Question

Everything was fine until I updated Sdk Version to 27. It says here that ViewHolder views must not be attached when created. But the attachToRoot parameter in my LayoutInflater is already set 'true'. Please explain me what could have caused this problem? Logcat :

06-02 11:40:15.669 22801-22801/com.bestworldgames.bestwordgame E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.bestworldgames.bestwordgame, PID: 22801
java.lang.IllegalStateException: ViewHolder views must not be attached when created. Ensure that you are not passing 'true' to the attachToRoot parameter of LayoutInflater.inflate(..., boolean attachToRoot)
at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6687)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5869)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5752)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5748)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2232)
at android.support.v7.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:556)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1519)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:614)
at android.support.v7.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3812)
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:3225)
at android.view.View.measure(View.java:18788)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:715)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
at android.view.View.measure(View.java:18788)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:715)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:141)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2643)
at android.view.View.measure(View.java:18788)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2100)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1216)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1452)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6013)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
at android.view.Choreographer.doCallbacks(Choreographer.java:670)
at android.view.Choreographer.doFrame(Choreographer.java:606)

Here is my RecyclerView Adapter :

public class GameTableAdapter extends RecyclerView.Adapter<GameTableAdapter.ViewHolder> {


private ArrayList<Litera> literas;
private LayoutInflater mInflater;
private Map<Integer, Integer> hashMap;
private Context context;
private ArrayList<Button> adapterItems;
private View mainView;
private int itemSize;

public GameTableAdapter(Context context, ArrayList<Litera> literas, Map<Integer, Integer> hashMap, int itemSize) {
    this.mInflater = LayoutInflater.from(context);
    this.literas = literas;
    this.hashMap = hashMap;
    this.context = context;
    this.adapterItems = new ArrayList<>();
    this.itemSize = itemSize;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = mInflater.inflate(R.layout.but_item, parent, false);
    parent.removeView(view);
    parent.addView(view);
    mainView = parent;
    return new ViewHolder(view);
}

@Override
public void onBindViewHolder(ViewHolder holder, final int position) {
    char mChar = literas.get(position).getCharValue();
    holder.item.setText(String.valueOf(mChar));
    if (this.hashMap.containsKey(position) && (hashMap.get(position)!=null)) {
        setImg(hashMap.get(position), holder.item);
        holder.item.setTextColor(context.getResources().getColor(R.color.colorWhite));
    }
}

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

public class ViewHolder extends RecyclerView.ViewHolder {
    Button item;
    ViewHolder(View itemView) {
        super(itemView);
        item = (Button) itemView.findViewById(R.id.item);
        item.setLayoutParams(new RecyclerView.LayoutParams(itemSize, itemSize));
        item.setTextSize(TypedValue.COMPLEX_UNIT_PX,(float)itemSize/2);
        adapterItems.add(item);
    }

}

public Litera getItem(int id) {
    return literas.get(id);
}

public Button getButItem(int id) {
    return adapterItems.get(id);
}

public View getMainView() {
    return mainView;
}

public void animateItem(int id) {
    adapterItems.get(id).setVisibility(View.INVISIBLE);
    adapterItems.get(id).setVisibility(View.VISIBLE);
}

}

in Fragment :

    recyclerView = (TouchableRecyclerView) rootView.findViewById(R.id.rv_chars);

...

public void setUpAdapter() {
        numberOfColumns = col;
        int itemSize = screenWidth / numberOfColumns;
        recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), numberOfColumns));
        adapter = new GameTableAdapter(getActivity(), literas, hashMapAllColors, itemSize);
        recyclerView.setAdapter(adapter);
        recyclerView.setNestedScrollingEnabled(false);
        recyclerView.setOnTouchListener(this);
    }

TouchableRecyclerView.java

public class TouchableRecyclerView extends RecyclerView {
    public TouchableRecyclerView(Context context) {
        super(context);
    }

    public TouchableRecyclerView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public TouchableRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public boolean performClick() {
        return super.performClick();
    }

}

in xml :

 <com.bestworldgames.bestwordgame.widgets.TouchableRecyclerView
        android:id="@+id/rv_chars"
        android:layout_below="@+id/tapped_word"
        android:paddingLeft="5dp"
        android:layout_centerHorizontal="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:overScrollMode="never"
        android:clickable="true"
        android:focusable="true"
        android:longClickable = "false">

    </com.bestworldgames.bestwordgame.widgets.TouchableRecyclerView>

but_item.xml

<?xml version="1.0" encoding="utf-8"?>
<Button xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/item"
    android:paddingRight="6dp"
    android:paddingBottom="8dp"
    android:animateLayoutChanges="true"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:background="@drawable/button_color_1"
    android:longClickable="false"
    android:clickable="false"
    android:focusable="false">
</Button>

This error occurs after working constructor public ViewHolder(View itemView) and before method onBindViewHolder(ViewHolder holder, final int position) . That's all I can say at the moment.

Answer 1

Try this: The parent.addView() method used here attach the view to the parent, so the problem aren't onCreateItemViewHolder custom implementation.

override onCreateMyViewHolder method into custom adapter like the others

 public class MyViewHolder extends RecyclerView.ViewHolder {
    public  Button item;

    public MyViewHolder(View view) {
        super(view);
        item = (Button) itemView.findViewById(R.id.item);
    item.setLayoutParams(new RecyclerView.LayoutParams(itemSize, itemSize));
    item.setTextSize(TypedValue.COMPLEX_UNIT_PX,(float)itemSize/2);
    adapterItems.add(item);
    }
}

Overide onCreate viewHolder like below:

@Override
public MyViewHolder onCreateMyViewHolder (ViewGroup parent) {

LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View mView= inflater.inflate(R.layout.but_item, parent, false);


return new MyViewHolder (mView);
}

Answer 2

Thanks Jarvis_J for helping me solve my problem! The solution is to set return type of overriding method by refer to a class.

Instead of:

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = mInflater.inflate(R.layout.but_item, parent, false);
    parent.removeView(view);
    parent.addView(view);
    mainView = parent;
    return new ViewHolder(view);
}

I had to do it:

@Override
public GameTableAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    LayoutInflater inflater = LayoutInflater.from(parent.getContext());
    View view = inflater.inflate(R.layout.but_item, parent, false);
    mainView = parent;
    return new GameTableAdapter.ViewHolder(view);
}

And there's really no need to be parent.removeView(view) parent.addView(view) .

I hope it'll help someone!