Var variablename: datatype = values // It is the regular initialization it accepts non-null values by default In this case, let’s go down the meet in the middle route.Web development, programming languages, Software testing & others fun main() We can meet somewhere in the middle and download the image the first time and again only after some amount of time has passed. We can only request it once and risk showing stale data.ģ. We can always request the image and waste bandwidth.Ģ. Let’s say we want to make a network call to download an avatar which may change from time to time. Since they are resolved statically though they give us another benefit, we can pass in a null reference and handle that without crashing however at the callsite we are just calling the null-safe function on the object. Behind the scenes an extension is resolved statically, if you have ever written a Util class then you are well aware of what this looks like. The typical way you might use an extension is when you want to add functionality to a class that you don’t own, but they allow you call the function directly on that class.
Just the other day I was working on a caching system and found a great way to use (perhaps abuse) another feature of Kotlin known as Extensions to call a function on a null reference without crashing. Not only that, there are still plenty of valid reasons to still use null in our applications, so writing null safe code is unfortunately still part of our job descriptions. However the language doesn’t entirely eradicate NPEs, if you try hard enough (or call non-Kotlin source code) you can still make your application crash from accessing a null reference.
Kotlin solves this problem by having a type system which can represent both nullable (indicated by a ? at the end of the class name) and non-null types. One of the major selling points about Kotlin is the ability to avoid the dreaded NullPointerException(NPE), also known as The Billion Dollar Mistake.
0 kommentar(er)
