在水平回收器视图中捕捉

Question

我有一个水平的回收器视图，我想在它中启用捕捉。我在SO上读了一些线程，发现这段代码工作得很好。我对回收器视图和布局管理器的内部工作原理了解不多，所以想问一下代码是否可以修改为:

1. 无论投掷速度如何，我只想向前或向后移动一件物品

2. 捕获速度慢。如果我将视图移动超过宽度的一半，下一个项目就会进入中心，但速度很慢。是否可以增加这一点，使snap是即时的?

关于如何实现上述行为的任何想法都将非常有帮助。

Answer 1

在其他代码的帮助下终于弄明白了:

public class FlingRecyclerView extends RecyclerView {
    int screenWidth;
    public FlingRecyclerView(Context context) {
        super(context);
        WindowManager windowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
        Display display = windowManager.getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        screenWidth = size.x;
    }
    public FlingRecyclerView(Context context, AttributeSet attrs) {
        super(context, attrs);
        WindowManager windowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
        Display display = windowManager.getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        screenWidth = size.x;
    }
    public FlingRecyclerView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        WindowManager windowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
        Display display = windowManager.getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        screenWidth = size.x;
    }
    @Override
    public boolean fling(int velocityX, int velocityY) {
        LinearLayoutManager linearLayoutManager = (LinearLayoutManager) getLayoutManager();
//these four variables identify the views you see on screen.
        int lastVisibleView = linearLayoutManager.findLastVisibleItemPosition();
        int firstVisibleView = linearLayoutManager.findFirstVisibleItemPosition();
        View firstView = linearLayoutManager.findViewByPosition(firstVisibleView);
        View lastView = linearLayoutManager.findViewByPosition(lastVisibleView);
//these variables get the distance you need to scroll in order to center your views.
//my views have variable sizes, so I need to calculate side margins separately.
//note the subtle difference in how right and left margins are calculated, as well as
//the resulting scroll distances.

        int leftMargin = (screenWidth - lastView.getWidth()) / 2;
        int rightMargin = (screenWidth - firstView.getWidth()) / 2 + firstView.getWidth();
        int leftEdge = lastView.getLeft();
        int rightEdge = firstView.getRight();
        int scrollDistanceLeft = leftEdge - leftMargin;
        int scrollDistanceRight = rightMargin - rightEdge;
//if(user swipes to the left)
        if (velocityX > 0) smoothScrollBy(scrollDistanceLeft, 0);
        else smoothScrollBy(-scrollDistanceRight, 0);
        return true;
    }
}

工作棒极了我的要求。