Hello! Can someone explain to me why recomposition...

# compose

[Mikolaj]

Hello!
Can someone explain to me why recomposition count in layout inspector is changing while my composable function is not run?

[Mikolaj]

A very basic example will be something like that:

My state class:

data class State(
    val text: String,
    val onClick: () -> Unit
)

My view model:

class ViewModelX : ViewModel() {
    private val _stateFlow: MutableStateFlow<State> = MutableStateFlow(State(text = "Hello, world1", onClick = ::updateStateReference))
    val stateFlow: StateFlow<State> = _stateFlow

    private fun updateStateReference() = viewModelScope.launch {
        _stateFlow.emit(stateFlow.value.copy())
    }
}

My view:

// ... in MainActivity.kt
        setContent {
            val state by viewModelX.stateFlow.collectAsState()
            Screen(state)
        }
// ...

@Composable
fun Screen(state: State) {
    MyButton(text = state.text, onClick = state.onClick)
}

@Composable
fun MyButton(text: String, onClick: () -> Unit) {
    Button(onClick) {
        Text(text = text)
    }
}

[Mikolaj]

Now every time i press button the recomposition count in layout inspector for Button goes up. But when I attach debugger it never runs into breakpoint that i set on Button composable 🤷

[Mikolaj]

In that case it was actually the ripple effect recomposing the Button 🤦

Helpful links:
• https://stackoverflow.com/questions/74294380/button-press-in-jetpack-compose-showing-multiple-recomposition
• https://www.jetpackcompose.app/articles/donut-hole-skipping-in-jetpack-compose