Call function when condition pass - ViewModel, LiveData, Transformations

Asked Apr 11 '19 at 08:35

Active Apr 11 '19 at 09:15

Viewed 447 times

I want to call a function in a ViewModel which returns nothing when a value is different from 0.

Here is the code I have so far, but it doesn't get triggered.

val categoryId = MutableLiveData<Int>()

val waitToCallApi: LiveData<Unit> = Transformations.map(categoryId) {
    if(it != 0) {
        getData()
    } else {
        // nothing
    }
}

I need this because categoryId gets its value after the init method call.

edited Apr 11 '19 at 09:15

asked Apr 11 '19 at 08:35

Robert Pal

why not return -1 ? – coroutineDispatcher Apr 11 '19 at 08:39
A `LiveData` has no real sense to me. If you need to listen to some events why not simply use something different than livedata? – MatPag Apr 11 '19 at 08:46
Any other idea that has the same effect in a ViewModel without a context reference would be ok. – Robert Pal Apr 11 '19 at 08:47
You probably need to handle those things with wrapper classes like those ones: https://github.com/google/iosched/tree/master/shared/src/main/java/com/google/samples/apps/iosched/shared/result – MatPag Apr 11 '19 at 08:59

Call function when condition pass - ViewModel, LiveData, Transformations

0 Answers0