Observable fields mapping

ObservableFields.kt

    val nameText = ObservableBoolean(nameHint) { it.isEmpty() }
    
    fun <T: Any> ObservableBoolean(o: ObservableField<T>, f:(T) -> Boolean): ObservableBoolean {
        return ObservableBoolean()
                .apply {
                    o.observe {
                        this.set(f(it!!))
                    }
                }
    }