findFirstVisibleItemPositions不适用于recycleview android

本文介绍了findFirstVisibleItemPositions不适用于recycleview android的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有这段代码：

mRecycleView.setOnScrollListener(new RecyclerView.OnScrollListener() { @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); int[] firstVisibleItemPositions = new int[getResources().getInteger(R.integer.news_numbers_column)]; int pastVisiblesItems = ((StaggeredGridLayoutManager)getLayoutManager()).findFirstVisibleItemPositions(firstVisibleItemPositions)[0]; } });

当我滚动我的recycleview时出现此错误：

When I scroll my recycleview I get this error:

java.lang.NullPointerException: Attempt to invoke virtual method 'int android.support.v7.widget.OrientationHelper.getStartAfterPadding()' on a null object reference at android.support.v7.widget.StaggeredGridLayoutManager$Span.findOneVisibleChild(StaggeredGridLayoutManager.java:2177) at android.support.v7.widget.StaggeredGridLayoutManager$Span.findFirstVisibleItemPosition(StaggeredGridLayoutManager.java:2153) at android.support.v7.widget.StaggeredGridLayoutManager.findFirstVisibleItemPositions(StaggeredGridLayoutManager.java:806) at info.lanouvelletribune.apps.android.ui.fragments.NewsFragment$1.onScrollStateChanged(NewsFragment.java:90) at android.support.v7.widget.RecyclerView.setScrollState(RecyclerView.java:751) at android.support.v7.widget.RecyclerView.onInterceptTouchEvent(RecyclerView.java:1535) at com.github.ksoichiro.android.observablescrollview.ObservableRecyclerView.onInterceptTouchEvent(ObservableRecyclerView.java:188) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2060) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2431) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2173) at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2390) at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1741) at android.app.Activity.dispatchTouchEvent(Activity.java:2826) at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2351) at android.view.View.dispatchPointerEvent(View.java:8590) at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4098) at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3964) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3488) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3541) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3507) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3515) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3488) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3541) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3507) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3617) at android

如何处理此错误并获得第一个可见项目位置？

How can I do to handle this error and get the first visible item position?

推荐答案

我测试了它这段代码和我一起工作

I tested it with this code and it works fine with me

int positionView = ((LinearLayoutManager)recyclerView.getLayoutManager()).findFirstVisibleItemPosition();

我使用了循环视图参数。

I used the recycle view parameter.