RecyclerVIew 自动滚动以显示新闻提要等中的所有元素， [英] RecyclerVIew auto scroll to display all the elements as in News Feed etc.,

问题描述

如何平滑地自动滚动 RecyclerView 以便用户可以看到 RecyclerView 的所有元素并从头开始再次滚动 - 如新闻提要等

How to auto scroll RecyclerView smoothly so that user can see all the elements of the RecyclerView and scroll again from the start - as in News Feed etc.

我知道 smoothScrollToPosition() 和 scrollToPosition() 但它们最终滚动到最后一个元素的速度太快了.

I know smoothScrollToPosition() and scrollToPosition() but they would just end up scrolling too fast to the last element.

我希望 RecyclerView 具有动画效果并缓慢移动.

I want the RecyclerView to be animated and move slowly.

推荐答案

只是为了稍微改进一下答案，它是具有平滑动画的自动滚动无穷大.

final int speedScroll = 1200;
final Handler handler = new Handler();
final Runnable runnable = new Runnable() {
    int count = 0;
    boolean flag = true;
    @Override
    public void run() {
        if(count < adapter.getItemCount()){
            if(count==adapter.getItemCount()-1){
                flag = false;
            }else if(count == 0){
                flag = true;
            }
            if(flag) count++;
            else count--;

            recyclerView.smoothScrollToPosition(count);
            handler.postDelayed(this,speedScroll);
        }
    }
};

handler.postDelayed(runnable,speedScroll);

这正是您的答案，但如果您链接到更流畅的动画，请使用 LayoutManager

This is exactly your answer but if you link to more smooth animation then use LayoutManager

recyclerView.setLayoutManager(new CustomLinearLayoutManager(mContext, LinearLayoutManager.HORIZONTAL, false));

控制动画改变 MILLISECONDS_PER_INCH 值.

public class CustomLinearLayoutManager extends LinearLayoutManager {
    public CustomLinearLayoutManager(Context context) {
        super(context);
    }

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

    public CustomLinearLayoutManager(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()) {
                    private static final float MILLISECONDS_PER_INCH = 200f;

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

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

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