java - RecyclerView : Inconsistency detected. 项目位置无效 - 为什么会这样？

Question

我们的 QA 检测到一个错误:发生了以下与 RecyclerView 相关的崩溃:`

java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid item position 2(offset:2).state:3

一个残酷的解决方法可能是在异常发生时捕获异常并从头开始重新创建 RecycverView 实例，以避免留下损坏的状态。

但是，如果可能的话，我想更好地理解问题(并可能从源头上解决它)，而不是掩盖它。

该错误很容易重现，滚动继续快速导致此崩溃，但一旦发生，它是致命的。

我的工作代码是:

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

public static final int VIEW_ITEM = 1;
public static final int VIEW_PROG = -1;
private static final int FADE_DURATION = 500;
int pastVisiblesItems, visibleItemCount, totalItemCount;
private List<VideoEntity> dataList;
private FragmentActivity activity;
private int visibleThreshold = 1;
//private int lastVisibleItem, totalItemCount;
//private boolean loading = false;
private OnLoadMoreListener onLoadMoreListener;
private RecyclerView.OnScrollListener recyclerciewScrollListener;
private RecyclerView recyclerView;
private boolean followLargeItemOnDataRender;
private boolean loading = false;
private boolean isLiveChannel = false;

public MoviesGridRecyclerViewDataAdapter(FragmentActivity fragmentActivity, final List<VideoEntity> dataList, RecyclerView recycler, boolean followLargeItemOnOddData, boolean isLiveChannels) {
    this.dataList = dataList;
    this.activity = fragmentActivity;
    this.followLargeItemOnDataRender = followLargeItemOnOddData;
    this.recyclerView = recycler;
    isLiveChannel = isLiveChannels;

    Log.e("VideoGridRVDataAdapter", "True");

    if (this.recyclerView.getLayoutManager() instanceof GridLayoutManager) {

        final GridLayoutManager gridLayoutManager = (GridLayoutManager) this.recyclerView.getLayoutManager();
        recyclerciewScrollListener = new RecyclerView.OnScrollListener() {

            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);

                if (dy > 0) //check for scroll down
                {
                    visibleItemCount = gridLayoutManager.getChildCount();
                    totalItemCount = gridLayoutManager.getItemCount();
                    pastVisiblesItems = gridLayoutManager.findFirstVisibleItemPosition();

                    if (!loading) {
                        if ((visibleItemCount + pastVisiblesItems) >= totalItemCount) {
                            loading = true;


                            if (onLoadMoreListener != null) {
                                onLoadMoreListener.onLoadMore(visibleItemCount + pastVisiblesItems);
                            }
                        }
                    }
                }
            }
        };

        this.recyclerView.addOnScrollListener(recyclerciewScrollListener);
    }
}


public void notifyDataLoadingStartProgress() {
    dataList.add(null);
    notifyItemInserted(dataList.size() - 1);
}

public void notifyDataLoaded() {
    dataList.remove(dataList.size() - 1);
    notifyItemRemoved(dataList.size());
    setLoaded();
}


public void resetItems(@NonNull List<VideoEntity> newDataSet) {
    loading = false;
    pastVisiblesItems = visibleItemCount = totalItemCount = 0;

    dataList.clear();
    addItems(newDataSet);
}

public void addItems(@NonNull List<VideoEntity> newDataSetItems) {
    dataList.addAll(newDataSetItems);
    postAndNotifyAdapter(new Handler());
}



public void addItem(VideoEntity item) {
    if (!dataList.contains(item)) {
        dataList.add(item);
        notifyItemInserted(dataList.size() - 1);
    }
}

public void removeItem(VideoEntity item) {
    int indexOfItem = dataList.indexOf(item);
    if (indexOfItem != -1) {
        this.dataList.remove(indexOfItem);
        notifyItemRemoved(indexOfItem);
    }
}

private void postAndNotifyAdapter(final Handler handler) {
    handler.post(new Runnable() {
        @Override
        public void run() {
            if (!recyclerView.isComputingLayout()) {
                try {
                    recyclerView.getRecycledViewPool().clear();
                    notifyDataSetChanged();
                } catch (IndexOutOfBoundsException ex) {
                }

            } else {
                postAndNotifyAdapter(handler);
            }
        }
    });
}

public void destroy() {
    this.recyclerView.removeOnScrollListener(recyclerciewScrollListener);
}


@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
    RecyclerView.ViewHolder vh;
    View v;
    if (viewType == VIEW_PROG) {
        v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_progressbar, viewGroup, false);
        vh = new ProgressViewHolder(v);

    } else {
        Integer layoutResourceId;

        if (isLiveChannel) {
            layoutResourceId = R.layout.item_video_grid_norma_hs_overfow_overdraw;

        } else {
            layoutResourceId = R.layout.item_video_linear_overdraw;

        }
        v = LayoutInflater.from(viewGroup.getContext()).inflate(layoutResourceId, viewGroup, false);
        vh = new MoviesItemRowHolder(this, dataList, v, activity);
    }
    return vh;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int i) {

    if (holder instanceof MoviesItemRowHolder) {
        VideoEntity singleItem = dataList.get(i);
        ((MoviesItemRowHolder) holder).bind(singleItem,dataList);
        //setScaleAnimation(holder.itemView);
    } else {
        ((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
    }
}

public boolean isLoading() {
    return loading;
}

public void setLoaded() {
    loading = false;
}

private void setFadeAnimation(View view) {
    AlphaAnimation anim = new AlphaAnimation(0.0f, 1.0f);
    anim.setDuration(FADE_DURATION);
    view.startAnimation(anim);
}

private void setScaleAnimation(View view) {
    ScaleAnimation anim = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
    anim.setDuration(FADE_DURATION);
    view.startAnimation(anim);
}

/**
 * Return the view type of the item at <code>position</code> for the purposes
 * of view recycling.
 * <p/>
 * <p>The default implementation of this method returns 0, making the assumption of
 * a single view type for the adapter. Unlike ListView adapters, types need not
 * be contiguous. Consider using id resources to uniquely identify item view types.
 *
 * @param position position to query
 * @return integer value identifying the type of the view needed to represent the item at
 * <code>position</code>. Type codes need not be contiguous.
 */
@Override
public int getItemViewType(int position) {
    //return position;

    return dataList.get(position) != null ? position : VIEW_PROG;
}

@Override
public int getItemCount() {
    return (null != dataList ? dataList.size() : 0);
}

public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) {
    this.onLoadMoreListener = onLoadMoreListener;
}

public List<VideoEntity> getItems() {
    return dataList;
}
}

请看看我的类(class)，让我知道出了什么问题，当我快速滚动时，这个崩溃发生在更少的设备上。

Stack Trace 是:

Fatal Exception: java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid item position 17(offset:17).state:18 android.support.v7.widget.RecyclerView{4266ee78 VFED.... .F....ID 0,0-480,625 #7f0902db app:id/recycler_view_list}, adapter:com.tapmad.tapmadtv.f.e@425896c0, layout:com.tapmad.tapmadtv.WrapContentLinearLayoutManager@424092b0, context:com.tapmad.tapmadtv.activities.SectionMoreActivityHS@4244c478
   at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline + 5923(RecyclerView.java:5923)
   at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition + 5858(RecyclerView.java:5858)
   at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition + 5854(RecyclerView.java:5854)
   at android.support.v7.widget.LinearLayoutManager$LayoutState.next + 2230(LinearLayoutManager.java:2230)
   at android.support.v7.widget.GridLayoutManager.layoutChunk + 557(GridLayoutManager.java:557)
   at android.support.v7.widget.LinearLayoutManager.fill + 1517(LinearLayoutManager.java:1517)
   at android.support.v7.widget.LinearLayoutManager.scrollBy + 1331(LinearLayoutManager.java:1331)
   at android.support.v7.widget.LinearLayoutManager.scrollVerticallyBy + 1075(LinearLayoutManager.java:1075)
   at android.support.v7.widget.GridLayoutManager.scrollVerticallyBy + 382(GridLayoutManager.java:382)
   at android.support.v7.widget.RecyclerView.scrollStep + 1832(RecyclerView.java:1832)
   at android.support.v7.widget.RecyclerView$ViewFlinger.run + 5067(RecyclerView.java:5067)
   at android.view.Choreographer$CallbackRecord.run + 791(Choreographer.java:791)
   at android.view.Choreographer.doCallbacks + 591(Choreographer.java:591)
   at android.view.Choreographer.doFrame + 560(Choreographer.java:560)
   at android.view.Choreographer$FrameDisplayEventReceiver.run + 777(Choreographer.java:777)
   at android.os.Handler.handleCallback + 725(Handler.java:725)
   at android.os.Handler.dispatchMessage + 92(Handler.java:92)
   at android.os.Looper.loop + 176(Looper.java:176)
   at android.app.ActivityThread.main + 5317(ActivityThread.java:5317)
   at java.lang.reflect.Method.invokeNative(Method.java)
   at java.lang.reflect.Method.invoke + 511(Method.java:511)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run + 1102(ZygoteInit.java:1102)
   at com.android.internal.os.ZygoteInit.main + 869(ZygoteInit.java:869)
   at dalvik.system.NativeStart.main(NativeStart.java)

非常感谢任何潜在客户。

Answer 1

我在你的代码中发现了问题

问题是当你清除arrayList时

dataList.clear();

您必须通知适配器数据集已更改。 else adapter不知道数据集被清空，计算出错

dataList.clear();
notifyDataSetChanged();

因此，recyclerview 适配器会知道发生了数据清除，并且会重新计算位置。当您添加新数据时，不会有任何不一致。