Suppose I have ScanActivity using jetpack compose that can scan Barcode, the result will shown in TextField and result will survive from configuration change(e.g screen rotation). I won't use StateFlow because after the result shown then I rotate my screen it will call API again, but the result become empty I want to keep the result.
ScanActivity:
class ScanActivity : BaseActivity(){
private val scanViewModel: ScanViewModel by viewModels()
override fun onCreate(savedInstanceState: Bundle?) {
setContent {
val detectedBarcode by scanViewModel.detectedBarcode.collectAsState(initial = null)
LaunchedEffect(detectedBarcode){
//API Call
...
//
scanViewModel.setBarcodeField(detectedBarcode?.rawValue ?: "")
}
MyTextField()
}}
ScanViewModel:
class ScanViewModel: ViewModel(){
val detectedBarcode = MutableSharedFlow<Barcode>()
val barcodeResultField = MutableLiveData<String>()
fun setBarcodeField(barcode: String) {
barcodeResultField.postValue(barcode)
}
}
My TextField:
@Composable
fun MyTextField(scanViewModel: ScanViewModel = viewModel()){
val barcode by scanViewModel.barcodeResultField.observeAsState("")
TextField(value = barcode, onValueChange = {brc ->
scanViewModel.setBarcodeField(brc)
},
label = {
Text(text = "Barcode Field")
})
}
