Question
How can I define a Kotlin property that has a private getter while allowing a public setter?
var status: String = ""
private set()
Answer
In Kotlin, you can achieve a private getter and a public setter by utilizing a backing field. A property can have its getter and setter visibility adjusted, but the visibility of the getter cannot be more restrictive than the property itself. To accomplish the requirement of having a private getter and a public setter, we will use a custom getter and setter on the property. Below, I’ll explain how to do this step-by-step.
class MyClass {
var status: String = ""
private set
// Public setter
fun setStatus(value: String) {
status = value
}
}
Causes
- Kotlin properties enforce visibility rules which state that the getter cannot be less visible than the property itself.
- The default generated getter and setter for a property have the same visibility level as the property.
Solutions
- Define a property with a custom visibility for the setter while providing a private setter within its declaration.
- Use a backing property that allows the getter to remain private and the setter to be public.
Common Mistakes
Mistake: Attempting to declare a property with a private getter directly which causes visibility errors.
Solution: Use a private backing field or a method for getting while maintaining the public setter.
Mistake: Not recognizing that the Kotlin generated getter cannot be more private than the property itself.
Solution: Use a custom method or logic that ensures the property can still be modified if required.
Helpers
- Kotlin private getter public setter
- Kotlin property visibility
- Kotlin Java interoperability
- Kotlin property handling
- Kotlin getter and setter example