Android 如何使用其他组件的位置来定位自定义弹出窗口

我有一个自定义弹出窗口:

        if (expanded) {
            Popup(
                onDismissRequest = {},
                properties = PopupProperties(
                    clippingEnabled = false
                ),
                popupPositionProvider = object : PopupPositionProvider {
                    override fun calculatePosition(
                        anchorBounds: IntRect,
                        windowSize: IntSize,
                        layoutDirection: LayoutDirection,
                        popupContentSize: IntSize
                    ): IntOffset {
                        return IntOffset(
                            x = textXPosition,
                            y = barYPosition
                        )
                    }
                }
            ) {
                Text(
                    text = "This is the popup content.",
                    modifier = Modifier.background(Color.White)
                )
            }
        }

式中，textXPosition和barYPosition的取值如下:

textXPosition:

        var textXPosition by remember { mutableStateOf(0) }

        Text(
            text = state.currentFileName,
            modifier = Modifier
                .weight(1f)
                .padding(start = 8.dp)
                .clickable { expanded = !expanded }
                .onGloballyPositioned { coordinates ->
                    textXPosition = coordinates.positionInRoot().x.toInt()
                }
        )

        if (expanded) {...}

barYPosition:

    var barYPosition by remember {
        mutableStateOf(0)
    }

    ActionBar(
        modifier = Modifier
            .height(36.dp)
            .background(Color(0xfffafafa))
            .onGloballyPositioned { coordinates ->
                barYPosition = coordinates.positionInRoot().y.toInt()
            }
    ...)

我最后得到的是图片上的:

这个 idea 是弹出窗口将直接在文本上方，但实际上有一个小缺口，我不知道为什么..