Custom border layout contains half of a circle

Question

I need create xml with two layout title and description. In title layout I need add border have half of circle in bottom left and right, and with description layout border have half of circle in top left and right. Here is my design

I can do it with create two half circle over line of rectangle radius border, but I don't want use this. How I can do it with another solution? Please give me key work or solution to do it! Thank you so much!

Answer 1

You can use the ShapeAppearanceModel defining a custom CornerTreatment to apply to the components. Something like:

    val radius = resources.getDimension(R.dimen.default_corner_radius)
    val title_layout = findViewById<LinearLayout>(R.id.title_layout)
    
    val titleShapeModel = ShapeAppearanceModel().toBuilder()
            .setTopLeftCorner(CornerFamily.ROUNDED, radius)
            .setTopRightCorner(CornerFamily.ROUNDED, radius)
            .setBottomLeftCorner(ConcaveRoundedCornerTreatment()).setBottomLeftCornerSize(radius)
            .setBottomRightCorner(ConcaveRoundedCornerTreatment()).setBottomRightCornerSize(radius)
            .build()
    val titleBackground = MaterialShapeDrawable(titleShapeModel)
    titleBackground.setStroke(1f, ContextCompat.getColor(this, R.color.colorPrimaryDark))

    ViewCompat.setBackground(title_layout, titleBackground)

where the ConcaveRoundedCornerTreatment is:

class ConcaveRoundedCornerTreatment : CornerTreatment() {

    override fun getCornerPath(
            shapePath: ShapePath,
            angle: Float,
            interpolation: Float,
            radius: Float
    ) {
        val interpolatedRadius = radius * interpolation
        shapePath.reset(0f, interpolatedRadius, ANGLE_LEFT, ANGLE_LEFT - angle)
        shapePath.addArc(
                -interpolatedRadius,
                -interpolatedRadius,
                interpolatedRadius,
                interpolatedRadius,
                ANGLE_BOTTOM,
                -angle
        )
    }

    companion object {
        const val ANGLE_LEFT = 180f
        const val ANGLE_BOTTOM = 90f
    }
}

Just do the same with the description layout:

If you are using a view like a CardView which has a built-in shapeAppearanceModel:

cardView.shapeAppearanceModel = cardView.shapeAppearanceModel.toBuilder()
        .setTopRightCorner(concaveRoundedCornerTreatment).
        .........
        .build()