如何控制recyclerView.smoothScrollToPosition(position)的滚动速度? [英] How can I control the scrolling speed of recyclerView.smoothScrollToPosition(position)?

问题描述

我有一个回收站视图，我想平滑向下滚动，然后以编程方式向上滚动到它，以便向用户显示其中的完整内容.

I have a recycler view, and I want a smooth scrolldown and then scrollup to it programatically to show the complete content in it to user.

我可以通过以下方式做到这一点:

I can do this by:

    final int height=recyclerView.getChildAt(0).getHeight();
    recyclerView.smoothScrollToPosition(height);
    recyclerView.postDelayed(new Runnable() {
        public void run() {
            recyclerView.smoothScrollToPosition(0);
                        }
    },200);

但是我想要放慢滚动速度，以使完整的内容清晰可见.

But what I want is to slow down the scrolling speed, so that the complete content gets visible clearly.

推荐答案

只需对答案进行一些改进:

Just to improve on the answer a little:

public class SpeedyLinearLayoutManager extends LinearLayoutManager {

    private static final float MILLISECONDS_PER_INCH = 5f; //default is 25f (bigger = slower)

    public SpeedyLinearLayoutManager(Context context) {
        super(context);
    }

    public SpeedyLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
    }

    public SpeedyLinearLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {

        final LinearSmoothScroller linearSmoothScroller = new LinearSmoothScroller(recyclerView.getContext()) {

            @Override
            public PointF computeScrollVectorForPosition(int targetPosition) {
                return super.computeScrollVectorForPosition(targetPosition);
            }

            @Override
            protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
                return MILLISECONDS_PER_INCH / displayMetrics.densityDpi;
            }
        };

        linearSmoothScroller.setTargetPosition(position);
        startSmoothScroll(linearSmoothScroller);
    }
}

然后将SpeedyLayoutManager设置为您的RecyclerView:

And then set SpeedyLayoutManager to your RecyclerView:

recyclerView.setLayoutManager(new SpeedyLinearLayoutManager(context, SpeedyLinearLayoutManager.VERTICAL, false);

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