android - 在 android 回收器 View 中确定快照结束事件

Question

我正在使用 LinearSnapHelper 捕捉到回收器 View 中的下一个项目。 如果捕捉成功，我需要采取行动。成功是指 snap 成功显示了下一个项目。因此，我正在寻找一个表明快照成功并显示下一个项目的事件。有没有这样的事件我可以听，采取适当的行动。

Answer 1

您可以为此使用自定义的 RecyclerView.OnScrollListener 和 findSnapView 通过在 SnapHelper

上做扩展功能

fun SnapHelper.getSnapPosition(recyclerView: RecyclerView): Int {
    val layoutManager = recyclerView.layoutManager ?: return RecyclerView.NO_POSITION
    val snapView = findSnapView(layoutManager) ?: return RecyclerView.NO_POSITION
    return layoutManager.getPosition(snapView)
}

这里是完整的代码

创建一个接口(interface)作为回调

interface OnSnapPositionChangeListener {
fun onSnapPositionChange(position: Int)
}

覆盖 RecyclerView.OnScrollListener()

class SnapOnScrollListener(private var mSnapHelper: SnapHelper, private var mOnSnapPositionChangeListener: OnSnapPositionChangeListener) : RecyclerView.OnScrollListener() {
private var snapPosition = RecyclerView.NO_POSITION

override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
    val snapPosition = mSnapHelper.getSnapPosition(recyclerView)
    val snapPositionChanged = this.snapPosition != snapPosition && snapPosition != RecyclerView.NO_POSITION
    if (snapPositionChanged) {
        mOnSnapPositionChangeListener
                .onSnapPositionChange(snapPosition)
        this.snapPosition = snapPosition
    }

}
}

      var  helper = LinearSnapHelper()
        recyclerview.onFlingListener = null
        helper.attachToRecyclerView(recyclerview)


recyclerview.addOnScrollListener( SnapOnScrollListener(helper, object : OnSnapPositionChangeListener {
        override fun onSnapPositionChange(position: Int) {
            //your code

        }
    }))