Kotlin Caveats

Calling a toString() on a nullable type

A thing to look out for when using the toString method in Kotlin is the handling of null in combination with the String?.

For example you want to get text from an EditText in Android.

You would have a piece of code like:

// Incorrect:
val text = view.textField?.text.toString() ?: ""

You would expect that if the field did not exists the value would be empty string but in this case it is "null".

// Correct:
val text = view.textField?.text?.toString() ?: ""