class MyClass {
object IO {
fun makeSomethingWithIO() { /* ... */ }
}
object Factory {
fun createSomething() { /* ... */ }
}
}
To instantly create a singleton instance that is scoped to a class, I often write /*...*/ which seems like an unidiomatic way of doing it. What's the better way?
It depends on what you need in each particular case. Your code suits well for storing state bound to a class which is initialized upon the first call to it.
If you don't need it to be connected with a class, just use object declaration:
data class User(val id: String, val name: String) {
class UserAccess : UserDao {
override fun add(user: User) { }
override fun remove(id: String) { }
}
}
用法:
fun main() {
val john = User("34", "John")
val userAccess = User.UserAccess()
userAccess.add(john)
}
data class User(val id: Long, val name: String) {
companion object {
val list by lazy {
print("Fetching user list...")
listOf("John", "Jane")
}
val settings by lazy {
print("Fetching settings...")
mapOf("Dark Theme" to "On", "Auto Backup" to "On")
}
}
}