在recyclerview中检测开始滚动和结束滚动

问题描述

我需要在recyclerview中检测滚动的开始/结束和方向.滚动侦听器有两种方法:onScrolled()和onScrollStateChanged().在滚动开始后调用第一个方法(实际上称为onScrolled()而不是onScrolling()).第二种方法提供有关状态的信息，但是我没有方向信息.我如何实现我的目标?

I need to detect the start/end and direction of scroll in a recyclerview. The scroll listener has two methods: onScrolled() and onScrollStateChanged(). The first method is called after the scroll is started (indeed is called onScrolled() and not onScrolling()). The second method gives information about the state but I don't have the direction information. How can I achieve my goal?

推荐答案

步骤1您可以创建一个扩展RecyclerView.OnScrollListener的类并覆盖这些方法

step 1 You can create a class extending RecyclerView.OnScrollListener and override these methods

public class CustomScrollListener extends RecyclerView.OnScrollListener {
    public CustomScrollListener() {
    }

    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        switch (newState) {
            case RecyclerView.SCROLL_STATE_IDLE:
                System.out.println("The RecyclerView is not scrolling");
                break;
            case RecyclerView.SCROLL_STATE_DRAGGING:
                System.out.println("Scrolling now");
                break;
            case RecyclerView.SCROLL_STATE_SETTLING:
                System.out.println("Scroll Settling");
                break;

        }

    }

    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        if (dx > 0) {
            System.out.println("Scrolled Right");
        } else if (dx < 0) {
            System.out.println("Scrolled Left");
        } else {
            System.out.println("No Horizontal Scrolled");
        }

        if (dy > 0) {
            System.out.println("Scrolled Downwards");
        } else if (dy < 0) {
            System.out.println("Scrolled Upwards");
        } else {
            System.out.println("No Vertical Scrolled");
        }
    }
}

第2步，因为不赞成使用setOnScrollListener，所以最好使用addOnScrollListener

step 2- Since setOnScrollListener is deprecated It is better to use addOnScrollListener

 mRecyclerView.addOnScrollListener(new CustomScrollListener());

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