RxJava Single

This is simpler version of an Observable. Singles work almost exactly the same as Observables. But instead of there being an onCompleted(), onNext(), and onError(), there are only two callbacks: onSuccess() and onError().

Code Setup

Make sure you require Internet permission in your manifest file.

<uses-permission android:name="android.permission.INTERNET" />

We need following dependencies for this project. Add the lines below to your app/build.gradle in your app project under dependencies.

def rxjava_version ="2.1.8"
def rxandroid_version = "2.0.1"
def retrofit_version ="2.0.2"
def gson_version ="2.6.2"
def retrofit_adapter ="1.0.0"

dependencies 
{
	// Retrofit, Gson
	implementation "com.google.code.gson:gson:$gson_version"
	implementation "com.squareup.retrofit2:retrofit:$retrofit_version"
	implementation "com.squareup.retrofit2:converter-gson:$retrofit_version"
	implementation "com.jakewharton.retrofit:retrofit2-rxjava2-adapter:$retrofit_adapter"

	// RxJava2
	implementation "io.reactivex.rxjava2:rxjava:$rxjava_version"
	implementation "io.reactivex.rxjava2:rxandroid:$rxandroid_version"
}

val apiService = ApiClient.client!!.create(ApiInterface::class.java)

        apiService.getWeatherReport(apiKey, "$latitude,$longitude").subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(object : SingleObserver<WeatherResponseDO> {
                override fun onSuccess(t: WeatherResponseDO) {
                    // Success case
                }

                override fun onSubscribe(d: Disposable) {
                }

                override fun onError(e: Throwable) {
                    // Failure case
                }
            })

Instead of using an Observer, we’re using a class called SingleObserver. It’s very similar to an Observer except that it just has the two methods we mentioned above: onSuccess()  and  onError(). A SingleObserver is to a Single what an Observer is to an Observable

Output