Mateusz Teteruk’s Post

4 Kotlin Property Delegates You Must Know👇🏻 Yesterday, we covered the delegation pattern in Kotlin. You know how to use it with classes. Today, let's focus on properties.  It's far more interesting! Property delegation in Kotlin allows you to delegate the responsibility of getting and setting a value of a property to a separate class. As you know, Kotlin has a lot to offer in terms of built-in solutions.  Let's go through some of them one by one. -> Lazy Initialization One of the most common use cases for property delegation is lazy initialization using the `lazy` function. This is particularly useful when the property initialization is expensive, and you want to delay it until the property is actually accessed. -> Observable Properties Another scenario is when you want to observe changes to a property, for example, to update the UI or log changes. Kotlin's standard library provides a `Delegates.observable()` that allows you to add a listener that gets notified every time the property value changes. -> Intercept Observable Properties Quite similar to `observable`, but with the possibility to intercept new value assignments, is a `vetoable` delegate. The handler passed to `vetoable` will be called before the assignment of a new property value. -> Storing Properties in a Map Sometimes, you might want to store properties of an object in a map rather than as separate fields. This can be particularly useful in dynamic situations like parsing JSON or working with scripting languages. Kotlin supports this pattern out of the box as well. We can probably find a few more examples, but let's wrap it up for now! Why should you use it? It's all about keeping your code clean and focused! Each class sticks to its responsibilities. Plus, Kotlin's syntax for delegation is super elegant, don't you think? What's your favourite delegate? I'd choose `lazy` for sure! Let me know in the comments! PS If you like such content, follow me for more. #Kotlin #Android