RecyclerVIew自动滚动显示新闻Feed等中的所有元素,

Question

如何自动RecyclerView平滑滚动,以便用户可以看到RecyclerView的所有元素并从头开始再次滚动 - 如同News Feed等.

我知道smoothScrollToPosition(),scrollToPosition()但他们最终会滚动到最后一个元素.

我希望RecyclerView能够动画并且移动缓慢.

Answer 1

只是为了改善答案,它是自动滚动无限和平滑动画.

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,但如果链接到更流畅的动画,则使用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);
    }
}

Answer 2

我认为这是最好的解决方案.

    final int speedScroll = 150;
    final Handler handler = new Handler();
    final Runnable runnable = new Runnable() {
        int count = 0;
        @Override
        public void run() {
            if(count < list.size()){
                recyclerView.scrollToPosition(++count);
                handler.postDelayed(this,speedScroll);
            }


        }
    };

    handler.postDelayed(runnable,speedScroll);

Answer 3

这是自动滚动 RecyclerView及其100%工作的最佳方式：

  RecyclerView recyclerView = findViewById(R.id.rv_id);

  final int time = 4000; // it's the delay time for sliding between items in recyclerview

    final Adapter adapter = new Adapter(dataItems);
    recyclerView.setAdapter(adapter);

    final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(rootView.getContext(), LinearLayoutManager.HORIZONTAL, false);
    recyclerView.setLayoutManager(linearLayoutManager);

    //The LinearSnapHelper will snap the center of the target child view to the center of the attached RecyclerView , it's optional if you want , you can use it
    final LinearSnapHelper linearSnapHelper = new LinearSnapHelper();
    linearSnapHelper.attachToRecyclerView(recyclerView); 

    final Timer timer = new Timer();
    timer.schedule(new TimerTask() {

        @Override
        public void run() {

            if (linearLayoutManager.findLastCompletelyVisibleItemPosition() < (adapter.getItemCount() - 1)) {

                linearLayoutManager.smoothScrollToPosition(recyclerView, new RecyclerView.State(), linearLayoutManager.findLastCompletelyVisibleItemPosition() + 1);
            }

            else if (linearLayoutManager.findLastCompletelyVisibleItemPosition() == (adapter.getItemCount() - 1)) {

                linearLayoutManager.smoothScrollToPosition(recyclerView, new RecyclerView.State(), 0);
            }
        }
    }, 0, time);