LiveData2Observable

private val number = MutableLiveData<Int>().also { it.value = 1 }
number.toObservable(this).map { "$it" }.subscribe(textView.text())

dependency:

allprojects {
	repositories {
		...
		maven { url 'https://jitpack.io' }
	}
}

dependencies {
        compile 'com.github.adgvcxz:livedata2observable:0.1.0'
}