ScrollView监听滑动到哪个子控件

来源：互联网发布：mahout算法库编辑：程序博客网时间：2024/04/30 00:55

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">情景：在一个scrollview里面有多个可以播放视频的item，可以上下滑动，当item可以见的时候视频自动开始播放。</span>

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);"></span>

<span style="font-family:Arial, Helvetica, sans-serif;"><span style="background-color: rgb(255, 255, 255);">一共3个文件</span></span>

show code

package com.example.beteng.scrollview;import android.os.Handler;import android.os.Message;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.widget.LinearLayout;import android.widget.ScrollView;public class MainActivity extends AppCompatActivity {    private boolean isScoll;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ScrollView myScrollview = (ScrollView) findViewById(R.id.scrollView);        myScrollview.setOnTouchListener(new View.OnTouchListener() {            private int lastY = 0;            private int touchEventId = -9983761;            Handler handler = new Handler() {                @Override                public void handleMessage(Message msg) {                    super.handleMessage(msg);                    View scroller = (View) msg.obj;                    if (msg.what == touchEventId) {                        if (lastY == scroller.getScrollY()) {                            //停止了                            double i = DensityUtils.px2dp(MainActivity.this, lastY);                            int itemShow = 0;                            if ((i<=50)) {                                itemShow = 1;                                Log.e("MainActivity", "显示了第" + 1 + "个");                            }else if (i>50&&i<=250) {                                itemShow = 2;                                Log.e("MainActivity", "显示了第" + 2 + "个");                            }else if (i>250&&i<=450) {                                itemShow = 3;                                Log.e("MainActivity", "显示了第" + 3 + "个");                            }else {

                                itemShow = (int) (i / (200+8))+2;                            }                            Log.e("MainActivity", "lastY:" + i);                            Log.e("MainActivity", "显示了第" + itemShow + "个");                        } else {                            handler.sendMessageDelayed(handler.obtainMessage(touchEventId, scroller), 1);                            lastY = scroller.getScrollY();                        }                    }                }            };            @Override            public boolean onTouch(View v, MotionEvent event) {                isScoll = false;                int eventAction = event.getAction();                int y = (int) event.getRawY();                switch (eventAction) {                    case MotionEvent.ACTION_UP:                        handler.sendMessageDelayed(handler.obtainMessage(touchEventId, v), 5);                        break;                    default:                        break;                }                return false;            }        });    }}

package com.example.beteng.scrollview;import android.content.Context;import android.util.TypedValue;/** * 常用单位转换的辅助类 * * * */public class DensityUtils{    private DensityUtils()    {        /* cannot be instantiated */        throw new UnsupportedOperationException("cannot be instantiated");    }    /**     * dp转px     *     * @param context     * @param val     * @return     */    public static int dp2px(Context context, float dpVal)    {        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,                dpVal, context.getResources().getDisplayMetrics());    }    /**     * sp转px     *     * @param context     * @param val     * @return     */    public static int sp2px(Context context, float spVal)    {        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,                spVal, context.getResources().getDisplayMetrics());    }    /**     * px转dp     *     * @param context     * @param pxVal     * @return     */    public static float px2dp(Context context, float pxVal)    {        final float scale = context.getResources().getDisplayMetrics().density;        return (pxVal / scale);    }    /**     * px转sp     *     * @param fontScale     * @param pxVal     * @return     */    public static float px2sp(Context context, float pxVal)    {        return (pxVal / context.getResources().getDisplayMetrics().scaledDensity);    }}

源码下载地址：https://github.com/yogkin/Scrollview.git

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