[英]LinearLayoutManager.findLastVisibleItemPosition() returns false position
我正在使用以下方法在RecyclerView
实现分页的 延迟加载 :
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition(); // starts with 0
if (!mIsLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
if (mOnLoadMoreListener != null) {
mOnLoadMoreListener.onLoadMore();
}
mIsLoading = true;
}
}
});
它在API级别> 22时可以正常工作。 但是,在API 22及以下版本上, onScrolled()
会被自身多次调用,直到所有页面都加载onScrolled()
。 最终导致应用崩溃,并显示以下错误:
java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder{52d05fac position=6 id=-1, oldPos=5, pLpos:5 scrap [attachedScrap] tmpDetached no parent} android.support.v7.widget.RecyclerView{52820a2c VFED.... .F....ID 0,213-656,3401 #7f0a0122 app:id/
at android.support.v7.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:5610)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5792)
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$LayoutState.next(LinearLayoutManager.java:2232)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1559)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1519)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:614)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3763)
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:3219)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15848)
at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1217)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.widget.ScrollView.onMeasure(ScrollView.java:321)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:739)
at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:91)
at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1361)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:809)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:141)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189)
at andro
另一方面,当我添加dy> 0条件时, onScrolled()
仅被调用一次:
if (!mIsLoading && totalItemCount <= (lastVisibleItem + visibleThreshold) && dy>0) {
.
.
.
}
如果有人遇到这样的问题或解决方案,可以分享他们的意见,我将不胜感激。 谢谢。
找到了答案:
我在xml布局的ScrollView内使用RecyclerView 。 我认为ScrollView滚动动作侦听器比API <= 22中的RecyclerView优先。 无论如何,我发现这个答案很有帮助。
注意:如果给RecyclerView一个固定的高度,它也可以在ScrollView中使用。
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