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Modifier in Compose Ui



Invoked with the size of the modified Compose UI element when the element is first measured or when the size of the element changes.

There are no guarantees onSizeChanged will not be re-invoked with the same size.

Using the onSizeChanged size value in a [MutableState] to update layout causes the new size value to be read and the layout to be recomposed in the succeeding frame, resulting in a one frame lag.

You can use onSizeChanged to affect drawing operations. Use [Layout] or [SubcomposeLayout] to enable the size of one component to affect the size of another.

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dependencies {


fun Modifier.onSizeChanged(
    onSizeChanged: (IntSize) -> Unit

Code Example


fun OnSizeChangedSample(name: String) {
    // Use onSizeChanged() for diagnostics. Use Layout or SubcomposeLayout if you want
    // to use the size of one component to affect the size of another component.
        "Hello $name",
        Modifier.onSizeChanged { size ->
            println("The size of the Text in pixels is $size")