android实现歌词自动滚动效果

package ru.org.piaozhiye.lyric; 
import java.io.File; 
import java.util.List; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.Path; 
import android.graphics.Typeface; 
import android.util.AttributeSet; 
import android.widget.TextView; 
/** 
 * @author root 
 * 
 */ 
public class LyricView extends TextView { 
 private Paint mPaint; 
 private float mX; 
 private static Lyric mLyric; 
 private Paint mPathPaint; 
 public String test = \"test\"; 
 public int index = 0; 
 private List<Sentence> list; 
 public float mTouchHistoryY; 
 private int mY; 
 private long currentDunringTime; // 当前行歌词持续的时间，用该时间来sleep 
 private float middleY;// y轴中间 
 private static final int DY = 50; // 每一行的间隔 
 public LyricView(Context context) { 
  super(context); 
  init(); 
 } 
 public LyricView(Context context, AttributeSet attr) { 
  super(context, attr); 
  init(); 
 } 
 public LyricView(Context context, AttributeSet attr, int i) { 
  super(context, attr, i); 
  init(); 
 } 
 private void init() { 
  setFocusable(true); 
  PlayListItem pli = new PlayListItem(\"Because Of You\", 
    \"/sdcard/MP3/Because Of You.mp3\", 0L, true); 
  mLyric = new Lyric(new File(\"/sdcard/MP3/Because Of You.lrc\"), pli); 
  list = mLyric.list; 
  // 非高亮部分 
  mPaint = new Paint(); 
  mPaint.setAntiAlias(true); 
  mPaint.setTextSize(22); 
  mPaint.setColor(Color.WHITE); 
  mPaint.setTypeface(Typeface.SERIF); 
  // 高亮部分 当前歌词 
  mPathPaint = new Paint(); 
  mPathPaint.setAntiAlias(true); 
  mPathPaint.setColor(Color.RED); 
  mPathPaint.setTextSize(22); 
  mPathPaint.setTypeface(Typeface.SANS_SERIF); 
 } 
 protected void onDraw(Canvas canvas) { 
  super.onDraw(canvas); 
  canvas.drawColor(0xEFeffff); 
  Paint p = mPaint; 
  Paint p2 = mPathPaint; 
  p.setTextAlign(Paint.Align.CENTER); 
  if (index == -1) 
   return; 
  p2.setTextAlign(Paint.Align.CENTER); 
  // 先画当前行，之后再画他的前面和后面，这样就保持当前行在中间的位置 
  canvas.drawText(list.get(index).getContent(), mX, middleY, p2); 
  float tempY = middleY; 
  // 画出本句之前的句子 
  for (int i = index - 1; i >= 0; i--) { 
   // Sentence sen = list.get(i); 
   // 向上推移 
   tempY = tempY - DY; 
   if (tempY < 0) { 
    break; 
   } 
   canvas.drawText(list.get(i).getContent(), mX, tempY, p); 
   // canvas.translate(0, DY); 
  } 
  tempY = middleY; 
  // 画出本句之后的句子 
  for (int i = index + 1; i < list.size(); i++) { 
   // 往下推移 
   tempY = tempY + DY; 
   if (tempY > mY) { 
    break; 
   } 
   canvas.drawText(list.get(i).getContent(), mX, tempY, p); 
   // canvas.translate(0, DY); 
  } 
 } 
 protected void onSizeChanged(int w, int h, int ow, int oh) { 
  super.onSizeChanged(w, h, ow, oh); 
  mX = w * 0.5f; // remember the center of the screen 
  mY = h; 
  middleY = h * 0.5f; 
 } 
 // 
 /** 
  * @param time 
  *   当前歌词的时间轴 
  * 
  * @return currentDunringTime 歌词只需的时间 
  */ 
 public long updateIndex(long time) { 
  // 歌词序号 
  index = mLyric.getNowSentenceIndex(time); 
  if (index == -1) 
   return -1; 
  Sentence sen = list.get(index); 
  // 返回歌词持续的时间，在这段时间内sleep 
  return currentDunringTime = sen.getDuring(); 
 } 
} 

package ru.org.piaozhiye; 
import java.io.IOException; 
import ru.org.piaozhiye.lyric.LyricView; 
import android.app.Activity; 
import android.media.MediaP ; 
import android.os.Bundle; 
import android.os.Handler; 
public class LyricDemo extends Activity { 
 private MediaP  mp; 
 private LyricView lyricView; 
 private String path = \"/sdcard/MP3/Because Of You.mp3\"; 
 /** Called when the activity is first created. */ 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.main); 
  lyricView = (LyricView) findViewById(R.id.audio_lrc); 
  mp = new MediaP (); 
  mp.reset(); 
  try { 
   mp.setDataSource(path); 
   mp.prepare(); 
  } catch (IllegalArgumentException e) { 
   // TODO Auto-generated catch block 
   e.printStackTrace(); 
  } catch (IllegalStateException e) { 
   // TODO Auto-generated catch block 
   e.printStackTrace(); 
  } catch (IOException e) { 
   // TODO Auto-generated catch block 
   e.printStackTrace(); 
  } 
  mp.start(); 
  new Thread(new UIUpdateThread()).start(); 
 } 
 class UIUpdateThread implements Runnable { 
  long time = 100; // 开始 的时间，不能为零，否则前面几句歌词没有显示出来 
  public void run() { 
   while (mp.isPlaying()) { 
    long sleeptime = lyricView.updateIndex(time); 
    time += sleeptime; 
    mHandler.post(mUpdateResults); 
    if (sleeptime == -1) 
     return; 
    try { 
     Thread.sleep(sleeptime); 
    } catch (InterruptedException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
   } 
  } 
 } 
 Handler mHandler = new Handler(); 
 Runnable mUpdateResults = new Runnable() { 
  public void run() { 
   lyricView.invalidate(); // 更新视图 
  } 
 }; 
}