Question

我尝试在 SelectionTracker 的帮助下在 RecyclerView 中实现项目选择功能，但是得到了 IllegalArgumentException ，并且堆栈跟踪并不直观，因为仅显示元数据。

这就是我构建跟踪器的方式

wordAdapter.tracker = new SelectionTracker.Builder<Long>(
                "mySelectionId",
                recyclerView,
                new StableIdKeyProvider(recyclerView),
                new MyDetailsLookUp(recyclerView),
                StorageStrategy.createLongStorage()
        ).withSelectionPredicate(
                SelectionPredicates.<Long>createSelectAnything()
        ).build();

MyDetailsLookUp 类

class MyDetailsLookUp extends ItemDetailsLookup<Long> {
        RecyclerView recyclerView;

        MyDetailsLookUp(RecyclerView recyclerView) {
            this.recyclerView = recyclerView;
        }

        @Nullable
        @Override
        public ItemDetails<Long> getItemDetails(@NonNull MotionEvent e) {
            View view = recyclerView.findChildViewUnder(e.getX(), e.getY());
            if (view != null) {
                //  getting individual view holders
                return ((WordAdapter.MyViewHolder) recyclerView.getChildViewHolder(view)).getItemDetails();
            }
            return null;
        }
    }

WordAdapter

中 ViewHolder 中的

getItemDetails 方法

ItemDetailsLookup.ItemDetails<Long> getItemDetails(){
            return new ItemDetailsLookup.ItemDetails<Long>(){
                @Override
                public int getPosition() {
                    return getAdapterPosition();
                }

                @Nullable
                @Override
                public Long getSelectionKey() {
                    return getItemId();
                }
            };
        }

Stacktrace 1

java.lang.IllegalArgumentException
        at androidx.core.util.Preconditions.checkArgument(Preconditions.java:38)
        at androidx.recyclerview.selection.DefaultSelectionTracker.anchorRange(DefaultSelectionTracker.java:269)
        at androidx.recyclerview.selection.MotionInputHandler.selectItem(MotionInputHandler.java:60)
        at androidx.recyclerview.selection.TouchInputHandler.onLongPress(TouchInputHandler.java:132)
        at androidx.recyclerview.selection.GestureRouter.onLongPress(GestureRouter.java:96)
        at android.view.GestureDetector.dispatchLongPress(GestureDetector.java:778)
        at android.view.GestureDetector.-wrap0(Unknown Source:0)
        at android.view.GestureDetector$GestureHandler.handleMessage(GestureDetector.java:293)
        at android.os.Handler.dispatchMessage(Handler.java:105)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6541)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

令人惊讶的是，我已经在Kotlin中实现了相同的代码，并且在那儿运行良好。我发现有类似问题this的SO帖子，该接受的答案建议传递自定义 ItemKeyProvider 而不是 StableIdKeyProvider 。因此，这样做会打我这个错误。

Stacktrace 2

java.lang.IllegalStateException: Two different ViewHolders have the same stable ID. Stable IDs in your adapter MUST BE unique and SHOULD NOT change.
     ViewHolder 1:ViewHolder{987472c position=1 id=-1, oldPos=-1, pLpos:-1} 
     View Holder 2:ViewHolder{e50e5f5 position=2 id=-1, oldPos=-1, pLpos:-1 not recyclable(1)} androidx.recyclerview.widget.RecyclerView{617d73 VFED..... .F....ID 42,42-1038,1542 #7f08007b app:id/recyclerview}, adapter:com.example.roomwordssample.WordAdapter@7ada430, layout:androidx.recyclerview.widget.GridLayoutManager@a15b8a9, context:com.example.roomwordssample.Main2Activity@ca1d275
        at androidx.recyclerview.widget.RecyclerView.handleMissingPreInfoForChangeError(RecyclerView.java:4058)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep3(RecyclerView.java:3982)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3652)
        at androidx.recyclerview.widget.RecyclerView.consumePendingUpdateOperations(RecyclerView.java:1877)
        at androidx.recyclerview.widget.RecyclerView$1.run(RecyclerView.java:407)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:911)
        at android.view.Choreographer.doCallbacks(Choreographer.java:723)
        at android.view.Choreographer.doFrame(Choreographer.java:655)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897)
        at android.os.Handler.handleCallback(Handler.java:789)
        at android.os.Handler.dispatchMessage(Handler.java:98)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6541)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

更新的跟踪器

wordAdapter.tracker = new SelectionTracker.Builder<Long>(
                "mySelectionId",
                recyclerView,
               new GetItemDetails(recyclerView, ItemKeyProvider.SCOPE_MAPPED),
                new MyDetailsLookUp(recyclerView),
                StorageStrategy.createLongStorage()
        ).withSelectionPredicate(
                SelectionPredicates.<Long>createSelectAnything()
        ).build();

CustomItemKeyProvider

class CustomItemKeyProvider extends ItemKeyProvider<Long> {
        RecyclerView recyclerView;

        CustomItemKeyProvider(RecyclerView recyclerView, int scope) {
            super(scope);
            this.recyclerView = recyclerView;
        }

        @Nullable
        @Override
        public Long getKey(int position) {
            return wordAdapter.getItemId(position);
        }

        @Override
        public int getPosition(@NonNull Long key) {
            RecyclerView.ViewHolder viewHolder = recyclerView.findViewHolderForItemId(key);
            return viewHolder == null ? RecyclerView.NO_POSITION : viewHolder.getLayoutPosition();
        }
    }

PS ：在将适配器设置为wordAdapter.setHasStableIds(true)

之前完成RecyclerView

Answer 1

在您的堆栈跟踪中：

2019-05-17 00:00:00.000

在上面的错误中，它表示列表中的位置1和2，您使用的是相同的ID，但必须唯一。为了与选择跟踪器一起使用，请确保您具有唯一的ID。通知列表您具有稳定的ID

java.lang.IllegalStateException: Two different ViewHolders have the same stable ID. Stable IDs in your adapter MUST BE unique and SHOULD NOT change. ViewHolder 1:ViewHolder{987472c **position=1 id=-1**, oldPos=-1, pLpos:-1} View Holder 2:ViewHolder{e50e5f5 **position=2 id=-1**, oldPos=-1, pLpos:-1 not recyclable(1)}

在RecyclerView.Adapter中，您需要确保每个变量都使用唯一

setHasStableIds(true)

RecyclerView项目选择抛出错误

1 个答案: