Android 开源在线音乐播放器

@Override
protected void onDraw(Canvas canvas) {
  // 1.绘制顶部虚线
  mTopLine.setBounds(0, getTop(), getWidth(), getTop() + mTopLineHeight);
  mTopLine.draw(canvas);
  // 2.绘制黑胶唱片外侧半透明边框
  mCoverBorder.setBounds(mDiscPoint.x - mCoverBorderWidth, mDiscPoint.y - mCoverBorderWidth,
      mDiscPoint.x + mDiscBitmap.getWidth() + mCoverBorderWidth, mDiscPoint.y +
          mDiscBitmap.getHeight() + mCoverBorderWidth);
  mCoverBorder.draw(canvas);
  // 3.绘制黑胶
  // 设置旋转中心和旋转角度，setRotate和preTranslate顺序很重要
  mDiscMatrix.setRotate(mDiscRotation, mDiscCenterPoint.x, mDiscCenterPoint.y);
  // 设置图片起始坐标
  mDiscMatrix.preTranslate(mDiscPoint.x, mDiscPoint.y);
  canvas.drawBitmap(mDiscBitmap, mDiscMatrix, null);
  // 4.绘制封面
  mCoverMatrix.setRotate(mDiscRotation, mCoverCenterPoint.x, mCoverCenterPoint.y);
  mCoverMatrix.preTranslate(mCoverPoint.x, mCoverPoint.y);
  canvas.drawBitmap(mCoverBitmap, mCoverMatrix, null);
  // 5.绘制指针
  mNeedleMatrix.setRotate(mNeedleRotation, mNeedleCenterPoint.x, mNeedleCenterPoint.y);
  mNeedleMatrix.preTranslate(mNeedlePoint.x, mNeedlePoint.y);
  canvas.drawBitmap(mNeedleBitmap, mNeedleMatrix, null);
}

@Override
protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  // 中心Y坐标
  float centerY = getHeight() / 2 + mTextSize / 2 + mAnimOffset;
 
  // 无歌词文件
  if (!hasLrc()) {
    float centerX = (getWidth() - mCurrentPaint.measureText(label)) / 2;
    canvas.drawText(label, centerX, centerY, mCurrentPaint);
    return;
  }
 
  // 画当前行
  String currStr = mLrcTexts.get(mCurrentLine);
  float currX = (getWidth() - mCurrentPaint.measureText(currStr)) / 2;
  canvas.drawText(currStr, currX, centerY, mCurrentPaint);
 
  // 画当前行上面的
  for (int i = mCurrentLine - 1; i >= 0; i--) {
    String upStr = mLrcTexts.get(i);
    float upX = (getWidth() - mNormalPaint.measureText(upStr)) / 2;
    float upY = centerY - (mTextSize + mDividerHeight) * (mCurrentLine - i);
    // 超出屏幕停止绘制
    if (upY - mTextSize < 0) {
      break;
    }
    canvas.drawText(upStr, upX, upY, mNormalPaint);
  }
 
  // 画当前行下面的
  for (int i = mCurrentLine + 1; i < mLrcTimes.size(); i++) {
    String downStr = mLrcTexts.get(i);
    float downX = (getWidth() - mNormalPaint.measureText(downStr)) / 2;
    float downY = centerY + (mTextSize + mDividerHeight) * (i - mCurrentLine);
    // 超出屏幕停止绘制
    if (downY > getHeight()) {
      break;
    }
    canvas.drawText(downStr, downX, downY, mNormalPaint);
  }
}