<#C04TPPEQKEJ|compose-android> Hi, I write a custo...

# compose-android

[dan]

#compose-android Hi, I write a custom Slider, after init data in LaunchedEffect, the mOffsetX is no 0, when I first time draw and the onHorizontalDrag callback, the value of mOffsetX is 0, what is the problem?

@Composable
fun Slider(percent: Float, modifier: Modifier = Modifier, onDragEnd:(percent:Float) -> Unit){
    var mOffsetX = remember { 0f }
    var mWidth = remember { 0 }
    var mOffsetInt by remember{ mutableStateOf(0) }
    val thumbWidth =with(LocalDensity.current) {14.dp.toPx().toInt()}
    LogUtil.i("Slider# percent:$percent")

    LaunchedEffect(key1 = percent > 0.0f) {
        if(percent > 0.0f && mOffsetInt == 0) {
            mOffsetX = mWidth * percent
            mOffsetInt = mOffsetX.roundToInt()
        }
        LogUtil.i("Slider# LaunchedEffect mWidth:$mWidth mOffsetX:$mOffsetX mOffsetInt:$mOffsetInt")
    }

    Box(modifier = modifier
        .onGloballyPositioned { coordinates ->
            val width = coordinates.boundsInParent().width
            mWidth = width.toInt() - thumbWidth
        },
    ){
        Spacer(
            modifier = Modifier
                .fillMaxWidth()
                .height(3.dp)
                .align(Alignment.Center)
                .background(BaseColor.graySlider, RoundedCornerShape(50))
                .drawWithContent {
                    drawContent()
                    drawRect(
                        color = BaseColor.bluePrimary,
                        size = Size(mOffsetInt.toFloat(), size.height)
                    )
                }
        )

        Spacer(
            modifier = Modifier
                .offset {
                    IntOffset(mOffsetInt, 0)
                }
                .size(14.dp)
                .background(BaseColor.bluePrimary, RoundedCornerShape(50))
                .drawWithContent {
                    drawContent()
                    drawCircle(
                        Color.White,
                        size.minDimension / 4.0f
                    )
                }
                .pointerInput(mOffsetX) {
                    detectHorizontalDragGestures(
                        onDragEnd = {
//                            LogUtil.i("Drag#onDragEnd")
                            onDragEnd(mOffsetInt / mWidth.toFloat())

                        },
                        onHorizontalDrag = { change: PointerInputChange, dragAmount: Float ->
//                            LogUtil.i("Drag#onHorizontalDrag: change:${change} dragAmount:${dragAmount}")
                            LogUtil.i("Slider# before dragAmount:$dragAmount mOffsetX:$mOffsetX")
                            mOffsetX += dragAmount
                            var offerInt = mOffsetX.roundToInt()
                            offerInt = if (offerInt > 0) offerInt else 0
                            offerInt = if (offerInt < mWidth) offerInt else mWidth
                            mOffsetInt = offerInt
                            LogUtil.i("Slider# dragAmount:$dragAmount mOffsetX:$mOffsetX offerInt:$offerInt")
                        }
                    )
                }
        )
    }
}