自动轮询的recycleView

最新推荐文章于 2024-07-15 23:29:12 发布

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最新推荐文章于 2024-07-15 23:29:12 发布

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CC 4.0 BY-SA版权

文章标签：移动开发 java

原文链接：http://www.cnblogs.com/loaderman/p/9679827.html

本文介绍了一个自定义的Android RecyclerView组件，名为AutoRecyclerView，它能够实现自动滚动功能。通过内部的AutoPollTask任务，该组件每隔设定的时间间隔自动向下滚动特定的像素距离。文章详细展示了如何在构造函数中初始化AutoPollTask，并提供了start和stop方法来控制自动滚动的状态。此外，还覆盖了onTouchEvent方法，确保在用户触摸屏幕时自动滚动暂停，提升用户体验。

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.MotionEvent;
import com.shiwen.oil.util.LoggerUtil;
import java.lang.ref.WeakReference;


public class AutoRecyclerView extends RecyclerView {
    private static final long TIME_AUTO_POLL = 16;
    AutoPollTask autoPollTask;
    private boolean running; //标示是否正在自动轮询
    private boolean canRun;//标示是否可以自动轮询,可在不需要的是否置false
    public AutoRecyclerView(Context context,  AttributeSet attrs) {
        super(context, attrs);
        autoPollTask = new AutoPollTask(this);
    }
    static class AutoPollTask implements Runnable {
        private final WeakReference<AutoRecyclerView> mReference;
        //使用弱引用持有外部类引用->防止内存泄漏
        public AutoPollTask(AutoRecyclerView reference) {
            this.mReference = new WeakReference<AutoRecyclerView>(reference);
        }
        @Override
        public void run() {
            AutoRecyclerView recyclerView = mReference.get();
            if (recyclerView != null && recyclerView.running &&recyclerView.canRun) {
                recyclerView.scrollBy(2, 2);
                recyclerView.postDelayed(recyclerView.autoPollTask,recyclerView.TIME_AUTO_POLL);
            }
        }
    }
    //开启:如果正在运行,先停止->再开启
    public void start() {
        if (running)
            stop();
        canRun = true;
        running = true;
        postDelayed(autoPollTask,TIME_AUTO_POLL);
    }
    public void stop(){
        running = false;
        removeCallbacks(autoPollTask);
    }
    @Override
    public boolean onTouchEvent(MotionEvent e) {

        switch (e.getAction()){
            case MotionEvent.ACTION_DOWN:
                if (running)
                    stop();
                break;
            case MotionEvent.ACTION_MOVE:
                if (running){
                    stop();
                }
                break;
            case MotionEvent.ACTION_UP:
                if (canRun)
                    start();
                break;
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_OUTSIDE:
                if (canRun)
                    start();
                break;
        }
        return super.onTouchEvent(e);
    }
}