Android實現字幕滾動的方法

本文實例介紹了安卓Android實現字幕滾動效果的方法。主要是一個現成的Java類文件實現的，該程序由Android達人Tony編寫，本次是轉發，還望原作者Tony不要介意。這個Android字幕滾動類的自定義功能比較多，可定義當前滾動到結尾時的停頓時間，單位：毫秒，還可設置當前的滾動速度，值越小，速度越快。

主要實現代碼如下：

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; 
   } 
 /**
 * 判斷當前是否為滾動狀態
 * @return the isScrolled
 */
 public boolean isScrolled() {
 return isScrolled;
 }
 /**
 * 開啟或者關閉自動滾動功能
 * @param isScrolled
 *      true為開啟，false為關閉
 */
 public void setScrolled(boolean isScrolled) {
 this.isScrolled = isScrolled;
 autoScroll();
 }
 /**
 * 獲取當前滾動到結尾時的停頓時間，單位：毫秒
 * @return the period
 */
 public long getPeriod() {
 return period;
 }
 /**
 * 設置當前滾動到結尾時的停頓時間，單位：毫秒
 * @param period
 *the period to set
 */
 public void setPeriod(long period) {
 this.period = period;
 }
 /**
 * 獲取當前的滾動速度，單位：毫秒，值越小，速度越快。
 * @return the speed
 */
 public long getSpeed() {
 return duration;
 }
 /**
 * 設置當前的滾動速度，單位：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);
 }
}