When trying to make a gradient from the background, the background is filled with one color-CodePudding

I'm creating an Android application and I needed to create a Drawable with a gradient background and text inside, but for some reason I don't have a gradient, and the entire background is filled with solid color
Class code:

class TestDrawable(textSize: Int = 16) : Drawable() {
    private val rect = RectF()
    private val paint = Paint(Paint.ANTI_ALIAS_FLAG)
    private val textPaint = TextPaint(Paint.ANTI_ALIAS_FLAG)
    private val textWidth: Int
    private val text: String

    private var backgroundGradient: LinearGradient = LinearGradient(
        0f, 0f, intrinsicWidth.toFloat(), 0f,
        intArrayOf(-0xb73320, -0xafa523, -0x41bf40, -0x457d5),
        floatArrayOf(0.06f, 0.34f, 0.73f, 1f),
        Shader.TileMode.CLAMP
    )

    override fun draw(canvas: Canvas) {
        rect.set(bounds)
        canvas.drawRoundRect(rect,
            AndroidUtilities.dp(2f).toFloat(),
            AndroidUtilities.dp(2f).toFloat(), paint)
        canvas.drawText(
            text,
            rect.left   AndroidUtilities.dp(5f),
            rect.top   AndroidUtilities.dp(12f),
            textPaint
        )
    }

    override fun getIntrinsicWidth(): Int {
        return textWidth   AndroidUtilities.dp((5 * 2).toFloat())
    }

    override fun getIntrinsicHeight(): Int {
        return AndroidUtilities.dp(16f)
    }

    init {
        textPaint.textSize = AndroidUtilities.dp(textSize.toFloat()).toFloat()
        textPaint.typeface = AndroidUtilities.getTypeface("fonts/rmedium.ttf")
        textPaint.color = -0x1000000

        //paint.style = Paint.Style.FILL
        paint.color = -0x1
        paint.shader = backgroundGradient
        backgroundGradient.setLocalMatrix(Matrix())

        text = "plus".uppercase()
        textWidth = ceil(textPaint.measureText(text).toDouble()).toInt()
    }
}

CodePudding user response：

You're initialising backgroundGradient when you declare the variable, and that sets the gradient width with a call to getIntrinsicWidth, which itself relies on textWidth having been initialised. But that initialisation happens in the init block, which is below backgroundGradient, so it hasn't run yet.

I haven't tested it but I'm guessing textWidth is still zero (they behave like Java objects/primitives in this situation) so you're getting a very tiny gradient and the rest of your background is just the end colour. Try initialising your gradient in init, after textWidth has been set