如何平滑列表项在特定位置的移动

Question

我有列表视图。当项目处于特定位置时，他会改变颜色。（见图）。在顶部（带有蓝色方块）-这就是我现在所拥有的。下来-我需要的。但是当滚动时，当项目在所需位置并改变颜色时，它不会顺利发生。该项目似乎跳到了所需的位置。我怎样才能使这个过程更顺利？谢谢

这是我的部分观点class:

public class TimeView extends View {
...........................

    @Override
    public void setOnScrollChangeListener(OnScrollChangeListener l) {
    }

    AbsListView.OnScrollListener scrollListener = new AbsListView.OnScrollListener() {

        @Override
        public void onScrollStateChanged(final AbsListView view, int scrollState) {
            if (scrollState == SCROLL_STATE_IDLE) {
                View childView = view.getChildAt(0);
                int position = view.getFirstVisiblePosition();
                if (-childView.getTop() > childView.getHeight() / 2) {
                    position++;
                }
             
              view.setSelection(position);
               }
        }

        @Override
        public void onScroll(final AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
            for (int i = 0; i < view.getChildCount(); i++) {
                View childView = view.getChildAt(i);
                if (i == 1) {
                    childView.setBackgroundResource(R.drawable.selected_color);

                } else {
                    childView.setBackgroundResource(R.drawable.no_select_color);
                }
            }
        }

    };

Answer 1

如果您改用 RecyclerView 而不是 ListView（无论如何您都应该这样做），您可以为此使用 SnapHelper：

SnapHelper helper = new LinearSnapHelper();
helper.attachToRecyclerView(recyclerView);

https://youtu.be/MBCuvneFEp0?t=1191

Answer 2

试试这个：

    @Override
    public void onScrollStateChanged(final AbsListView view, int scrollState) {
        if (scrollState == SCROLL_STATE_IDLE) {
            View firstView = view.getChildAt(0);
            Rect rect = new Rect(0, 0, firstView.getWidth(), firstView.getHeight());
            view.getChildVisibleRect(firstView, rect, null);
            int position = view.getFirstVisiblePosition();
            if (rect.height() < (firstView.getHeight() / 2)) {
                position++;
            }
            final int finalPosition = position;
            view.postDelayed(new Runnable() {
                @Override
                public void run() {
                    view.smoothScrollToPositionFromTop(finalPosition, 0, 500);
                }
            }, 1);
        }
    }

更新：上面的代码有一个恒定的稳定时间（500ms）。下面的代码有一个恒定的捕捉速度（0.2 pixel/ms，这意味着滚动 up/down 一个像素需要 5ms）。

    final static int SCROLL_TIME_PER_PIXEL = 5; // Time(ms) to snap a pixel.
    @Override
    public void onScrollStateChanged(final AbsListView view, int scrollState) {
        if (scrollState == SCROLL_STATE_IDLE) {
            View firstView = view.getChildAt(0);
            Rect rect = new Rect(0, 0, firstView.getWidth(), firstView.getHeight());
            view.getChildVisibleRect(firstView, rect, null);
            int position = view.getFirstVisiblePosition();
            int offset = rect.height();
            if (rect.height() < (firstView.getHeight() / 2)) {
                position++;
            } else offset = firstView.getHeight() - rect.height();
            final int finalPosition = position; // Snap to position.
            final int finalOffset = offset; // Snap distance in pixels.
            view.postDelayed(new Runnable() {
                @Override
                public void run() {
                    view.smoothScrollToPositionFromTop(finalPosition, 0, finalOffset * SCROLL_TIME_PER_PIXEL);
                }
            }, 1);
        }
    }

如何平滑列表项在特定位置的移动

How to smooth the movement of a list item at a specific position

android

scroll

android-listview

smooth-scrolling