Android Development with Kotlin

The let function

Another tool to deal with nullable variables is the let function. This is actually not an operator, nor a language special construct. It is a function defined in the Kotlin standard library. Let's see the syntax of let combined with the safe call operator:

    override fun onCreate(savedInstanceState: Bundle?) { 
        super.onCreate(savedInstanceState) 
 
        savedInstanceState?.let { 
            println(it.getBoolean("isLocked")) // 1 
        } 
    } 

1. savedInstanceState inside the let function can be accessed using the it variable.

As mentioned before, the right-hand expression of the safe call operator will be only evaluated if the left-hand side is not null. In this case, the right-hand side is a let function that takes another function (lambda) as a parameter. ...