Android实现字幕滚动的方法

package com.tony.autoscroll;import android.content.Context;import android.os.Handler;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.widget.ScrollView;/** * @author Tony */public class AutoScrollView extends ScrollView { private final Handler handler   = new Handler(); private long     duration   = 50; private boolean    isScrolled  = false; private int      currentIndex = 0; private long     period    = 1000; private int      currentY   = -1; private double   x; private double   y; private int type = -1; /** * @param context */ public AutoScrollView(Context context) { this(context, null); } /** * @param context * @param attrs */ public AutoScrollView(Context context, AttributeSet attrs) { this(context, attrs, 0); } /** * @param context * @param attrs * @param defStyle */ public AutoScrollView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } public boolean onTouchEvent(MotionEvent event) { int Action = event.getAction(); switch (Action) {  case MotionEvent.ACTION_DOWN:  x=event.getX();  y=event.getY();  if (type == 0) {   setScrolled(false);        }  break;  case MotionEvent.ACTION_MOVE:  double moveY = event.getY() - y;  double moveX = event.getX() - x;  Log.d("test", "moveY = " + moveY + " moveX = " + moveX );  if ((moveY>20||moveY<-20) && (moveX < 50 || moveX > -50) && getParent() != null) {   getParent().requestDisallowInterceptTouchEvent(true);         }  break;  case MotionEvent.ACTION_UP:  if (type == 0) {   currentIndex = getScrollY();   setScrolled(true);        }  break;  default:  break; }    return super.onTouchEvent(event);  }  @Override    public boolean onInterceptTouchEvent(MotionEvent p_event)    {   Log.d("test", "onInterceptTouchEvent");     return true;    }  /** * 判断当前是否为滚动状态 * @return the isScrolled */ public boolean isScrolled() { return isScrolled; } /** * 开启或者关闭自动滚动功能 * @param isScrolled *      true为开启，false为关闭 */ public void setScrolled(boolean isScrolled) { this.isScrolled = isScrolled; autoScroll(); } /** * 获取当前滚动到结尾时的停顿时间，单位：毫秒 * @return the period */ public long getPeriod() { return period; } /** * 设置当前滚动到结尾时的停顿时间，单位：毫秒 * @param period *the period to set */ public void setPeriod(long period) { this.period = period; } /** * 获取当前的滚动速度，单位：毫秒，值越小，速度越快。 * @return the speed */ public long getSpeed() { return duration; } /** * 设置当前的滚动速度，单位：毫秒，值越小，速度越快。 * @param speed *the duration to set */ public void setSpeed(long speed) { this.duration = speed; } public void setType(int type){ this.type = type; } private void autoScroll() { handler.postDelayed(new Runnable() {  @Override  public void run() {  boolean flag = isScrolled;  if (flag) {   //Log.d("test", "currentY = " + currentY + " getScrollY() = "+ getScrollY() );   if (currentY == getScrollY()) {   try {    Thread.sleep(period);   } catch (InterruptedException e) {    e.printStackTrace();   }   currentIndex = 0;   scrollTo(0, 0);   handler.postDelayed(this, period);   } else {   currentY = getScrollY();   handler.postDelayed(this, duration);   currentIndex++;   scrollTo(0, currentIndex * 1);   }  } else {  //currentIndex = 0;  //scrollTo(0, 0);  }  } }, duration); }}