java - RecyclerView异步设置holder时插入新项崩溃

Question

viewholder有一个textview和imageview
textview显示用户姓名
imageview显示用户头像

在onbindviewholder时会根据item的id向服务器请求该用户的信息
由于请求是异步的，当请求成功回调设置textview和imageview的时候列表插入新信息，就会报错

错误信息如下：

java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder{a2d62b7 position=2 id=-1, oldPos=1, pLpos:1 scrap [attachedScrap] tmpDetached no parent}
    at android.support.v7.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:5046)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5177)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5158)
    at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2061)
    at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1445)
    at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1408)
    at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:580)
    at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3330)
    at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3186)
    at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3632)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.support.v4.view.ViewPager.onLayout(ViewPager.java:1799)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1077)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
    at android.view.View.layout(View.java:15718)
    at android.view.ViewGroup.layout(ViewGroup.java:5039)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2129)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1886)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1103)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5949)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:788)
    at android.view.Choreographer.doCallbacks(Choreographer.java:601)
    at android.view.Choreographer.doFrame(Choreographer.java:571)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:774)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5308)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:913)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:708)

Answer 1

報錯資訊不足, 無法判斷是什麼原因造成的.

所有的圖片非同步載入框架都不會考慮下面這個問題:

目前ViewHolder是否仍是請求前的ViewHolder

不論是AdapterView還是RecyclerView都有視圖重用的機制, 重用的視圖肯定是ItemViewType相同的視圖, 既然ItemViewType相同, 那麼用戶代碼的處理邏輯應當就是相同的.

如果自己實作一套圖片非同步載入框架的話, 可以參考Android官網文檔: Processing Bitmaps Off the UI Thread
另外, 不建議佔用View的tag屬性, 因為你有可能需要使用tag作為它用.

Answer 2

你報錯是因為在非ui線程更新介面吧...

為了防止非同步載入出現圖片錯亂，可以給view加入tag，在非同步任務完成後根據tag決定是否載入。

Answer 3

這種應該是先判斷本地是否有緩存，沒有則向伺服器取得。取得完畢後更新adapter對應的數據，更新列表即可。