Android-使用RecyclerView左右横向滚动

Question

我制作了一个自定义LayoutManager，用于在单击左键或右键后平滑滚动。仅向左滚动时一切正常！对，computeScrollVectorForPosition从不调用事件。什么东西？我试过在正确的时候设置mReverseLayout，但这没有帮助。有什么我没有做/忽略的吗？

public class SmoothScrollLayoutManager extends LinearLayoutManager {
private static final float MILLISECONDS_PER_INCH =  50f;
private Context context;
public boolean shouldGoRight = false;
public SmoothScrollLayoutManager(Context context, int orientation, boolean reverseLayout) {
    super(context, orientation, reverseLayout);
    this.context = context;
}
@Override
public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {
    LinearSmoothScroller smoothScroller = new LinearSmoothScroller(context) {
        @Override
        public PointF computeScrollVectorForPosition(int targetPosition) {
            if (getChildCount() == 0) {
                return null;
            }
            final int firstChildPos = getPosition(getChildAt(0));
            final int direction = targetPosition < firstChildPos != shouldGoRight ? -1 : 1;
            return new PointF(direction, 0);
        }
        @Override
        protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
            return MILLISECONDS_PER_INCH / displayMetrics.densityDpi;
        }
    };
    smoothScroller.setTargetPosition(position);
    startSmoothScroll(smoothScroller);
}

}

Answer 1

comupteScrollVectorForPosition只是为了找出LinearSmoothScroller必须滚动才能最终找到元素的方向。如果LinearSmoothScroller已经想知道元素在哪里，它将不会调用此函数。对于要显示的已经加载的元素，例如右侧的元素，就是这种情况。