Kotlin/Android: Finding all Views of type T recursively

Question

So I have this extension function for ViewGroup :

inline fun <reified T : View> ViewGroup.allViewsOfType(action: (T) -> Unit) 
{
    val views = Stack<View>()

    afterMeasured {
        views.addAll((0 until childCount).map(this::getChildAt))
    }

    while (!views.isEmpty()) {
        views.pop().let {
            if (it is T) action(it)
            if (it is ViewGroup) {
                afterMeasured {
                    views.addAll((0 until childCount).map(this::getChildAt))
                }
            }
        }
    }
}

And I use it like this:

tabs.allViewsOfType<Button> { Log.i("Dale", it.text.toString()) }

But somehow it doesn't work. Anything that I'm doing wrong?

Btw, tabs is a LinearLayout that contains three Buttons in it.

score 2 · Accepted Answer · answered Oct 18 '18 at 03:55

Why do you use afterMeasure in the particular case?

I just removed afterMeasure:

inline fun <reified T : View> ViewGroup.allViewsOfType(action: (T) -> Unit) {
    val views = Stack<View>()

    views.addAll((0 until childCount).map(this::getChildAt))

    while (!views.isEmpty()) {
        views.pop().let {
            if (it is T) action(it)
            if (it is ViewGroup) {
                views.addAll((0 until childCount).map(this::getChildAt))
            }
        }
    }
}

Replaced Log.i() logger with simple Kotlin's println():

tabs.allViewsOfType<Button> {
    println("Dale: ${it.text}")
}

And now your function works just fine:

I/System.out: Dale: Button 4
              Dale: Button 3
              Dale: Button 2
              Dale: Button 1

Kotlin/Android: Finding all Views of type T recursively

1 Answers1