SeekBar.java 文件源码

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    secondaryPaint.setAlpha(255);
    canvas.drawRect(0, 0, canvas.getWidth(), 2, secondaryPaint);

    int currentWidth = (int) (canvas.getWidth() * ((float) progress / maxProgress));
    for (int i = 0; i < maxProgress; i += 10) {
        int width = (int) (canvas.getWidth() * ((float) i / maxProgress));
        secondaryPaint.setAlpha(Math.max(255 - (int) ((float) Math.abs(width - currentWidth) * 1000 / canvas.getWidth()), 0));
        canvas.drawRect(width - 1, 0, width + 1, ConversionUtils.getPixelsFromDp(i % 20 == 0 ? 6 : 4), secondaryPaint);
    }

    canvas.drawRect(0, 0, currentWidth, 2, accentPaint);
    canvas.drawRect(currentWidth - 1, 0, currentWidth + 1, ConversionUtils.getPixelsFromDp(10), accentPaint);
}