Navigation bar的注意事项详解

　　@objc private func rightButtonClicked(_ sender: AnyObject) {

　　navigationController?.navigationBar.isTranslucent = !navigationController!.navigationBar.isTranslucent

　　updateLabelContent()

　　}

　　private func updateLabelContent() {

　　title = navigationController!.navigationBar.isTranslucent ? "Translecent" : "Opaque"

　　let frameLabelOrigin = frameLabel.frame.origin

　　frameLabel.text = "Frame label. x = (frameLabelOrigin.x), y = (frameLabelOrigin.y)"

　　let constraintLabelOrigin = constraintLabel.frame.origin

　　constraintLabel.text = "Constraint label. x = (constraintLabelOrigin.x), y = (constraintLabelOrigin.y)"

　　print("(title)")

　　print("Status bar frame:", UIApplication.shared.statusBarFrame) // (0.0, 0.0, 375.0, 20.0)

　　print("Navigation bar frame:", navigationController!.navigationBar.frame) // (0.0, 20.0, 375.0, 44.0)

　　}