ViewDumpAccessibilityService.kt

class ViewDumpAccessibilityService : AccessibilityService() {
    ...
    
    override fun onAccessibilityEvent(event: AccessibilityEvent) {
        Log.d("!!!", "...")
        printLeaves(event.source)
        Log.d("!!!", "...")
    }

    private fun printLeaves(info: AccessibilityNodeInfo?) {
        if (childCount(info) == 0 && info?.text != null) {
            Log.d("!!!", info.text.toString())
        } else {
            printLeavesForEachChildIn(info)
        }
    }

    private fun printLeavesForEachChildIn(info: AccessibilityNodeInfo?) {
        for (i in 0 until childCount(info)) {
            printLeaves(info?.getChild(i))
        }
    }

    private fun childCount(info: AccessibilityNodeInfo?) = info?.childCount ?: 0
}