用Kotlin帮我写一个Android自定义View进度条，进度条颜色是渐变色，宽高可以自行设置

好的，以下是用 Kotlin 编写的 Android 自定义 View 进度条的代码，进度条颜色为渐变色，宽高可以自行设置：

class GradientProgressBar(context: Context, attrs: AttributeSet) : View(context, attrs) {

    private var progress = 0f
    private var barWidth = 0f
    private var barHeight = 0f
    private var gradientColors = intArrayOf(Color.RED, Color.YELLOW, Color.GREEN)

    private val paint = Paint(Paint.ANTI_ALIAS_FLAG)
    private val rectF = RectF()

    init {
        val typedArray = context.obtainStyledAttributes(attrs, R.styleable.GradientProgressBar)
        barWidth = typedArray.getDimension(R.styleable.GradientProgressBar_barWidth, 0f)
        barHeight = typedArray.getDimension(R.styleable.GradientProgressBar_barHeight, 0f)
        gradientColors = typedArray.getIntArray(R.styleable.GradientProgressBar_gradientColors) ?: gradientColors
        typedArray.recycle()
    }

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)

        paint.shader = LinearGradient(0f, 0f, width.toFloat(), 0f, gradientColors, null, Shader.TileMode.CLAMP)

        rectF.set(0f, 0f, progress / 100 * width, barHeight)
        canvas.drawRoundRect(rectF, barHeight / 2, barHeight / 2, paint)
    }

    fun setProgress(progress: Float) {
        this.progress = progress
        invalidate()
    }
}

注意：该代码仅供参考，可能需要根据实际需求进行修改和优化。