TriangleShapeView

TriangleShapeView.kt

package your.package.name

import android.content.Context
import android.graphics.*
import android.util.AttributeSet
import android.view.View

class TriangleShapeView @JvmOverloads constructor(
        context: Context,
        attrs: AttributeSet? = null,
        defStyle: Int = 0
) : View(context, attrs, defStyle) {

    var text = ""
        set(value) {
            field = value
            textPaint.getTextBounds(value, 0, value.length, textBounds)
            invalidate()
        }

    private val fillPaint = Paint()
    private val textPaint = Paint()
    private val textBounds = Rect()
    private val fillPath = Path()

    init {
        val scale = resources.displayMetrics.density

        fillPaint.color = Color.parseColor("#4d000000")
        fillPaint.isAntiAlias = true

        textPaint.isAntiAlias = true
        textPaint.color = Color.WHITE
        textPaint.textSize = 16 * scale
        textPaint.typeface = Typeface.create(Typeface.DEFAULT, Typeface.BOLD)
        textPaint.getTextBounds(text, 0, text.length, textBounds)
    }

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        val desiredWidth = Math.round(textBounds.width() * 2f)

        val widthMode = MeasureSpec.getMode(widthMeasureSpec)
        val widthSize = MeasureSpec.getSize(widthMeasureSpec)
        val width: Int
        if (widthMode == MeasureSpec.EXACTLY) {
            width = widthSize
        } else if (widthMode == MeasureSpec.AT_MOST) {
            width = Math.min(desiredWidth, widthSize)
        } else {
            width = desiredWidth
        }
        setMeasuredDimension(width, width)
    }

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

        fillPath.reset()
        fillPath.moveTo(0f, 0f)
        fillPath.lineTo(width.toFloat(), height.toFloat())
        fillPath.lineTo(width.toFloat(), 0f)
        fillPath.close()

        canvas?.let {
            it.drawPath(fillPath, fillPaint)
            it.save()
            it.rotate(45f, width / 2f, height / 2f)
            it.drawText(text, width / 2f - textBounds.width() / 2f, height / 4f + textBounds.height() / 2f, textPaint)
            it.restore()
        }
    }
}