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#compose
Title
# compose
g
Grigorii Yurkov
10/27/2020, 7:22 AMHow am I supposed to preview composable function which invokes
viewModel()m
Mikael Alfredsson
10/27/2020, 7:29 AMyou shouldn’t connect them in a “hard” way.
Let your composable take a lambda with the correct signature (same as the function you want to call) and in the preview you can send in a dummy expression, while in the real usage you send in a reference to your viewmodel function.
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Copy code
// function in Viewmodel
fun getText() :String {
return "RealText"
}
// usage in real code
SomeText(textFetcher = model::getText)
@Preview
@Composable
fun previewSomeText(){
SomeText(textFetcher = {"test text"})
}
@Composable
fun SomeText(textFetcher : ()-> String ){
Text(text = textFetcher())
}g
Grigorii Yurkov
10/27/2020, 7:35 AMYeah, thank you, I got it
But, I think, you gave wrong example. Why do we need lambda here.
Copy code
// usage in real code
SomeText(textFetcher = viewModel.getText())
@Preview
@Composable
fun previewSomeText(){
SomeText("test text")
}
@Composable
fun SomeText(text: String){
Text(text = text)
}m
Mikael Alfredsson
10/27/2020, 8:11 AMsorry, that was just an example function, it could be a function that returns different data depending on input, then you need the lambda (I should have added an parameter to the function)
j
Javier
10/27/2020, 8:17 AMI had the same problem and I did previews for each state the screen can have instead of preview de entire screen composable which has the ViewModel
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