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#compose
Title
# compose
a
Artur Matsehor
06/16/2020, 2:45 PMHi everyone
I'm making a Compose-MVVM application and trying to implement network requests and make UI react to responses. And now I'm struggling on how to do it properly
So here's my pseudo-code
Copy code
@Composable
fun SampleScreen() {
SampleScreenBody(viewModel = SampleViewModel())
}
@Composable
fun SampleScreenBody(viewModel: SampleViewModel) {
Button(onClick = {
viewModel.doSmth("Parameter") { response ->
if (response == "Success") {
//TODO: this is where I want to, for ex, move to another screen
//or show a dialog.
//How?
}
}
}) {
Text("Text")
}
}a
andylamax
06/16/2020, 2:48 PMSpeaking as a rookie in this, so bare with me on this one
First: I don't think you should pass your viewmodel to a compose function. But do pass your exposed live data
☝️ 1
a
Artur Matsehor
06/16/2020, 2:48 PMAnd what if I don't want to use neither Rx or LiveData ?
a
andylamax
06/16/2020, 2:49 PMIf it is MVVM you are doing, you must have an observable pattern in your viewmodel
then, the exposed observable should be passed down
h
henrikhorbovyi
06/16/2020, 2:51 PMIf you don't want to use
LiveDataRXobservableStateFlowBut as @andylamax said: If you are doing MVVM you have to use the observable pattern
a
Artur Matsehor
06/16/2020, 2:53 PMWell, even if I'll use LiveData/Rx/Flow/Channel, how it is got to change things ?
Okay, I can use LiveData.observeAsState to get some State<T> object. But where and how should I declare the state variable ?
Copy code
@Composable
fun SampleScreenBody(viewModel: SampleViewModel) {
Button(onClick = {
val resultState = viewModel.doSmth("Parameter").observeAsState()
// ???
}) {
Text("Text")
}
}a
andylamax
06/16/2020, 3:03 PM Copy code
// If you are using viewModel
data class User(val name: String)
class VM : ViewModel {
private val _user = MutableLiveData<User>
val user : LiveData get() = _value
fun updateUser(name: String) {
_user.value = User(name)
}
}
class Activity : AppCompatActivity {
private lateinit var vm:VM
override fun onCreate(bundle: Bundle?) {
vm = ViewModelProvidors.of(this)
setContent {
SampleScreen(vm.user.value) {vm.updateUser(it)}
}
}
}
@Composable
fun SampleScreen(user:User,onUserNameChanged:(String)->Unit) {
// . . . User UI Implementation
Button(onClick = {
onUserNameChanged("New User")
}) {
Text(user.name)
}
}➕ 1
Sorry for the late response. I am relatively new to slack
Copy code
// Or Even this
data class User(val name: String)
class VM : ViewModel {
private val _user = MutableLiveData<User>
val user : LiveData get() = _value
fun updateUser(name: String) {
_user.value = User(name)
}
}
class Activity : AppCompatActivity {
private lateinit var vm:VM
override fun onCreate(bundle: Bundle?) {
vm = ViewModelProvidors.of(this)
setContent {
SampleScreen(vm.user) {vm.updateUser(it)}
}
}
}
@Composable
fun SampleScreen(u:LiveData<User>,onUserNameChanged:(String)->Unit) {
// . . . User UI Implementation
val user = u.asObservableState()
Button(onClick = {
onUserNameChanged("New User")
}) {
Text(user.name)
}
}a
Artur Matsehor
06/17/2020, 9:31 PMThanks for your help!
I did pretty much what you've gave (with some complications) and it worked)
a
andylamax
06/18/2020, 11:53 AMwelcome @Artur Matsehor
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