I have a repository setup like this
class ServerTimeRepo @Inject constructor(private val retrofit: Retrofit){
var liveDataTime = MutableLiveData<TimeResponse>()
fun getServerTime(): LiveData<TimeResponse> {
val serverTimeService:ServerTimeService = retrofit.create(ServerTimeService::class.java)
val obs = serverTimeService.getServerTime()
obs.subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).unsubscribeOn(Schedulers.io())
.subscribe(object : Observer<Response<TimeResponse>> {
override fun onComplete() {
}
override fun onSubscribe(d: Disposable) {
}
override fun onNext(t: Response<TimeResponse>) {
val gson = Gson()
val json: String?
val code = t.code()
val cs = code.toString()
if (!cs.equals("200")) {
json = t.errorBody()!!.string()
val userError = gson.fromJson(json, Error::class.java)
} else {
liveDataTime.value = t.body()
}
}
override fun onError(e: Throwable) {
}
})
return liveDataTime
}
}
Then I have a viewmodel calling this repo like this
class ServerTimeViewModel @Inject constructor(private val serverTimeRepo: ServerTimeRepo):ViewModel() {
fun getServerTime(): LiveData<TimeResponse> {
return serverTimeRepo.getServerTime()
}
}
Then I have an activity where I have an onClickListener where I am observing the livedata, like this
tvPWStart.setOnClickListener {
val stlv= serverTimeViewModel.getServerTime()
stlv.observe(this@HomeScreenActivity, Observer {
//this is getting called multiple times??
})
}
I don't know what's wrong in this. Can anyone point me in the right direction? Thanks.
Issue is that every time your ClickListener gets fired, you observe LiveData again and again. So, you can solve that problem by following solution :
Take a MutableLiveData object inside your ViewModel privately & Observe it as LiveData.
class ServerTimeViewModel @Inject constructor(private val serverTimeRepo: ServerTimeRepo):ViewModel() {
private val serverTimeData = MutableLiveData<TimeResponse>() // We make private variable so that UI/View can't modify directly
fun getServerTime() {
serverTimeData.value = serverTimeRepo.getServerTime().value // Rather than returning LiveData, we set value to our local MutableLiveData
}
fun observeServerTime(): LiveData<TimeResponse> {
return serverTimeData //Here we expose our MutableLiveData as LiveData to avoid modification from UI/View
}
}
Now, we observe this LiveData directly outside of ClickListener and we just call API method from button click like below :
//Assuming that this code is inside onCreate() of your Activity/Fragment
//first we observe our LiveData
serverTimeViewModel.observeServerTime().observe(this@HomeScreenActivity, Observer {
//In such case, we won't observe multiple LiveData but one
})
//Then during our ClickListener, we just do API method call without any callback.
tvPWStart.setOnClickListener {
serverTimeViewModel.getServerTime()
}