How to loop through all UIButtons in my Swift view?

Shortened and updated for Swift 3 & 4

for case let button as UIButton in self.view.subviews {
    button.setTitleForAllStates("")
}

This code should work:

for view in self.view.subviews as [UIView] {
    if let btn = view as? UIButton {
        btn.setTitleForAllStates("")
    }
}

You need to iterate through the subViews array.