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[英]Android: HorizontalScrollView smoothScroll animation time
[英]Catch Animation Event of SmoothScroll in RecyclerView [Android]
我有一个带有PageSnapHelper的GridLayout RecyclerView,它基本上就像一个Vertical Linear RecyclerView(我继承了代码,不知道为什么这样做)。 目标是突出显示当前居中在视图中的项目。 滚动是由两个菜单项驱动的代码完成的,以模拟远程前进和后退。 滚动视图效果很好。 问题似乎是当我听到滚动事件的结束时,会出现动画,这会影响我的代码以在项目周围绘制突出显示。 这是我用来根据菜单项滚动视图的代码:
@Override
public boolean onOptionsItemSelected(MenuItem item) {
//Get which arrow was pressed
int id = item.getItemId();
//Get count of items
int itemCount = recyclerView.getAdapter().getItemCount();
//Condition to moving down the list
if (id == R.id.next) {
//Make sure we're within bounds of the of the view from the top
if(count>=itemCount-1) {
return super.onOptionsItemSelected(item);
}
//Increment to count to next ViewHolder
count++;
//Condition for moving up list
} else if (id == R.id.prev) {
//Make sure we're within bounds
if(count == 0){
return super.onOptionsItemSelected(item);
}
//Decremennt to previous ViewHolder
count--;
}
//Scroll the RecyclerView to the position we want
layoutManager.setIsNext(id == R.id.next);
recyclerView.smoothScrollToPosition(count);
//If the item is already in view, then no scroll event is necessary and we can access the ViewHolder
HighlightViewHolder(count);
//In the event that the ViewHolder is off-screen listen for the end of the scrolling event to ensure the ViewHolder
//is created and in correct position on the screen
RecyclerView.OnScrollListener scrollListener = new RecyclerView.OnScrollListener() {
//Add a listener to that looks out for when the scrolling is complete
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
Log.i("ScrollListener", "Scrolling has ended");
HighlightViewHolder(count);
recyclerView.removeOnScrollListener(this);
}
};
recyclerView.addOnScrollListener(scrollListener);
return super.onOptionsItemSelected(item);
当应用程序第一次开始并且我是前进按钮时,第一项突出显示正常:
我期望发生的是当滚动事件结束时,项目处于其居中位置。 基于我所看到的,我认为有一些动画事件仍在发生,我应该寻找完成。 我的突出显示代码依赖于所讨论的视图位于其预期位置。 我是android的新手,我对RecyclerView动画的搜索把我带到了ItemAnimator。 但阅读文档,我不确定这是否是我正在寻找的。 有任何想法吗?
我找不到任何与我正在寻找的事件相关的事件所以我继续使用Handler等待任意时间,然后再绘制高亮显示。 我更新了Listener,如下所示:
//Add a listener to that looks out for when the scrolling is complete
@Override
public void onScrolled(final RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
Handler handler = new Handler();
Runnable task = new Runnable() {
@Override
public void run() {
HighlightViewHolder(count);
}
};
handler.postDelayed(task, 500);
recyclerView.removeOnScrollListener(this);
}
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