Hi All anyone know when I use coroutine on custom view onDraw just for experiment purpose it got drawn at weird coordinate ``` override fun onDraw canvas Canvas super onDraw canvas CoroutineScope Dispatchers Default launch lt add coroutine canvas drawLine 0f 0f width toFloat height toFloat strokePaint ``` More detail with image <https stackoverflow com questions 70014160 why did canvas draw in coroutine background thread draw in weird position|here>

override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        CoroutineScope(Dispatchers.Default).launch { // <-- add coroutine
            canvas.drawLine(
                0f, 0f,
                width.toFloat(), height.toFloat(),
                strokePaint
            )
        }
    }

More detail (with image) here

:not-kotlin: 1

Nick Allen

11/18/2021, 5:02 AM

Looks like you are calling

drawLine

while the "CUSTOM" text view is drawing. Every view draws to the same canvas. Translation and scale can be changed for every view that is drawn. See

Canvas

methods with descriptions that reference "matrix".

👍🏻 1

This is not Kotlin or coroutines related at all. You'd get similar weird behavior with Java code and/or any other background thread.

elye

11/18/2021, 5:24 AM

Makes sense. While it’s on the background, it’s drawn on the same canvas at a different coordinate measurement. Thanks! Sorry, I thought it was coroutine related, apparently it’s generic multithreading. 🙏 Thanks @Nick Allen

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