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.MediaPlayer; import android.os.Bundle; import android.os.Handler; public class LyricDemo extends Activity {  private MediaPlayer 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 MediaPlayer();  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  }  }; }