问题描述
我正在实现一个扩展 RowsSupportFragment 的片段。
问题陈述：我有一个远程源列表 source，其中包含在绑定列表行时异步获取的列表列表。列表返回后，其中一些是空的，需要从 UI 中删除：它们需要从 ListRowPresenter/ObjectAdapter 中删除，但 我无法确定如何在不使应用程序崩溃的情况下完全删除列表行。 例外情况如下：
at androidx.leanback.widget.ListRowPresenter.onBindRowViewHolder(ListRowPresenter.java:661)
at androidx.leanback.widget.RowPresenter.onBindViewHolder(RowPresenter.java:601)
at androidx.leanback.widget.Presenter.onBindViewHolder(Presenter.java:140)
at androidx.leanback.widget.ItemBridgeAdapter.onBindViewHolder(ItemBridgeAdapter.java:422)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7308)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6175)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6441)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6281)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6277)
at androidx.leanback.widget.GridLayoutManager.getViewForPosition(GridLayoutManager.java:1102)
at androidx.leanback.widget.GridLayoutManager$2.createItem(GridLayoutManager.java:1628)
at androidx.leanback.widget.SingleRow.appendVisibleItems(SingleRow.java:113)
at androidx.leanback.widget.Grid.appendOneColumnVisibleItems(Grid.java:389)
at androidx.leanback.widget.GridLayoutManager.appendOneColumnVisibleItems(GridLayoutManager.java:1852)
at androidx.leanback.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:2282)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4277)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3980)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4546)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1083)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1855)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1855)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.widget.ScrollView.onLayout(ScrollView.java:1552)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1812)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1656)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1565)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
这是我尝试过的：
调用 topLevelRowsAdapter.clear(indexOfRowToRemove) 会使应用程序崩溃。
调用 topLevelRowsAdapter[indexOfRowToRemove] = ListRow(ArrayObjectAdapter()) 会移除可见行，但会留下一个光标在上下滚动时仍可停留的行。
这是我正在尝试做的事情的简化版本：
class MyFragment : RowsSupportFragment() {
private val listRowPresenter = ListRowPresenter(FocusHighlight.ZOOM_FACTOR_NONE)
private val topLevelRowsAdapter = SparseArrayObjectAdapter(listRowPresenter)
override fun onViewCreated(view: View,savedInstanceState: Bundle?) {
super.onViewCreated(view,savedInstanceState)
topLevelRowsAdapter.setHasstableIds(true)
source.forEachIndexed { index,listToGet ->
val adapterForRow =
ArrayObjectAdapter()
// the list to get is bound to the UI,and the index corresponds to the ListRow that the list lives in -- this is passed so we can update
adapterForRow.add(Pair(index,listToGet))
topLevelRowsAdapter[newIndex] =
ListRow(HeaderItem(listToGet.headerText),adapterForRow)
}
}
this.adapter = topLevelRowsAdapter
}
// After a row is bound and the network request comes back this is called.
override fun asyncCallback(listToGet: Pair<Int,CustomListObject>) {
onTransitionPrepare()
onTransitionStart()
if (CustomListObject.listsForRow.isNotEmpty()) {
// List from network is not empty,update the UI with the items that came back. This works!
val updatingRow = (topLevelRowsAdapter[listToGet.first] as? ListRow)
(updatingRow?.adapter as ArrayObjectAdapter).setItems(
CustomListObject.listsForRow,diffUtil
)
} else {
// The list came back empty and it needs to be removed from the UI
// This causes a crash
topLevelRowsAdapter.clear(listToGet.first)
// This works but there is a "blank" row that the cursor can land on
topLevelRowsAdapter[listToGet.first] = ListRow(ArrayObjectAdapter())
}
ontransitionend()
}
}
我也尝试用一个空行子类化 ListRow 来替换该行，如下所示，但滚动时它似乎仍然是可聚焦的：
class EmptyRow : ListRow(HeaderItem(null),ArrayObjectAdapter()) {
override fun isRenderedAsRowView(): Boolean {
return false
}
}
我是否忽略了某些东西，或者我是否遇到了 Leanback RowsSupportFragment 实施的限制？
解决方法
暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！
如果你已经找到好的解决方法，欢迎将解决方案带上本链接一起发送给小编。
小编邮箱:dio#foxmail.com (将#修改为@）