How would I write this in idiomatic Kotlin? - 2

Question

I asked a question: How would I write this in idiomatic Kotlin?

and now I had an idea for short this idiom. like below

private fun getTouchX(): Int = when(arguments) 
     containsKey(KEY_DOWN_X) -> getInt(KEY_DOWN_X)
     else -> centerX() 
}

containsKey and getInt are arguments's method.

Of course this is not correct idiom for when.
is there any possible way to do this?

arguments is Bundle class in Android framework. you can see at below https://developer.android.com/reference/android/os/Bundle.html https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/os/Bundle.java https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/os/BaseBundle.java

Answer 1

From the information you've provided I can only give you this answer:

private fun getTouchX(): Int = arguments.run {
    if (containsKey(KEY_DOWN_X)) getInt(KEY_DOWN_X)
    else centerX()
}

If arguments is nullable, it can be like this:

private fun getTouchX(): Int = arguments?.run {
    if (containsKey(KEY_DOWN_X)) getInt(KEY_DOWN_X)
    else null
} ?: centerX()