根据int颜色值获取带透明度的颜色

/**
 * 获取带透明度的颜色
 * @param color 不带透明度的颜色
 * @param alpha 透明度 0-1.0f
 * @return
 */
fun getAlphaColor(color: Int, alpha: Float): Int {
    val mAlpha = (255 * alpha).toInt()
    val red = color and 0xff0000 shr 16
    val green = color and 0x00ff00 shr 8
    val blue = color and 0x0000ff
    return Color.argb(mAlpha, red, green, blue)
}

Java版：

public static int getAlphaColor(int color, float alpha) {
    int mAlpha = (int) (255 * alpha);
    int red = (color & 0xff0000) >> 16;
    int green = (color & 0x00ff00) >> 8;
    int blue = (color & 0x0000ff);
    return Color.argb(mAlpha, red, green, blue);
}