Null safety operator for function variable in Kotlin

Question

In my Kotlin app I have nullable variable like this

private var myCallback : (() -> Unit)? = null

Is it possible to use null safety operator ? to call it? This gives me a compilation error.

myCallback?()

I found only this ugly way for a call if it is not null

 if(myCallback != null)
     myCallback!!()

Possible duplicate of [How do I idiomatically call a nullable lambda in Kotlin?](https://stackoverflow.com/questions/51733552/how-do-i-idiomatically-call-a-nullable-lambda-in-kotlin) — Alexey Soshin, Aug 15 '18 at 20:09

score 7 · Accepted Answer · answered Aug 15 '18 at 20:06

7

You can call it as follows:

 myCallback?.invoke()

The () syntax on variables of function types is simply syntax sugar for the invoke() operator, which can be called using the regular safe call syntax if you expand it.

answered Aug 15 '18 at 20:06

yole

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Null safety operator for function variable in Kotlin

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