CODEWITHSUNDEEP
androidnullkotlinkotlin-null-safety
Fanale
Fanale

Reputation: 845

Kotlin !! Operator usage makes code not clear

I am writing a Kotlin application, I've been studying this language for a little bit and I noticed that to create a variable you have to explicitly define if it can be null and then you use the ? operator.

Now, my question. Sometimes I have to define a global variable (a Fragment in this case), so I need to make it null, because I cannot initialize it yet

In java I don't have this problem because the first thing I do after declaring it is initializing in the onCreate() like this

TurboFragment fragment = null;

@Override
public void onCreate(Bundle savedInstanceState) {

    ...

    fragment = adapter.getCurrentFragment();
}

And then I can use it without syntax problems In Kotlin is different, because I have to do like that

private var fragment: TurboFragment? = null

override fun onCreate(savedInstanceState: Bundle?) {

    ...

    fragment = adapter!!.currentFragment
    fragment!!.foo()
    var x = fragment!!.sampleInt
}

Now, every time I call an instance of fragment i have to use the null-safe !! operator. This makes my code a mess, because for every line I have at least one !! operator and it looks really unclear if it's so frequent, especially if you have 5 or more variables like that. Is there a way to simplify the code or the nature of this language is like that?

Upvotes: 4

Views: 188

Answers (1)

Alex Romanov
Alex Romanov

Reputation: 11963

Consider using Late-Initialized Properties. They're intended for your use-case.

private lateinit var fragment: TurboFragment

However, you should keep in mind that accessing a lateinit property before it has been initialized throws an exception. That means you should use them only if you are absolutely sure, they will be initialized.

print(fragment)  // UninitializedPropertyAccessException is thrown

Upvotes: 6

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