import UIKit
class ViewController: UIViewController {
@IBOutlet weak var nameField: UITextField!
@IBOutlet weak var numberField: UITextField!
@IBOutlet weak var sliderLabel: UILabel!
@IBOutlet weak var leftSwitch: UISwitch!
@IBOutlet weak var rightSwitch: UISwitch!
@IBOutlet weak var doSomethingButton: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
sliderLabel.text = "50"
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func textFieldDoneEditing(sender:UITextField){
sender.resignFirstResponder()
}
@IBAction func backgroundTap(sender : UIControl){
nameField.resignFirstResponder()
numberField.resignFirstResponder()
}
@IBAction func sliderChanged(sender: AnyObject) {
let progress = lroundf(sender.value)
sliderLabel.text = "\(progress)"
}
@IBAction func switchChanged(sender: UISwitch) {
let setting = sender.on
leftSwitch.setOn(setting, animated:true )
rightSwitch.setOn(setting,animated:true )
}
@IBAction func toggleControls(sender: UISegmentedControl) {
if sender.selectedSegmentIndex == 0{
leftSwitch.hidden = false
rightSwitch.hidden = false
doSomethingButton.hidden = true
}else{
leftSwitch.hidden = true
rightSwitch.hidden = true
doSomethingButton.hidden = false
}
}
@IBAction func buttonPressed(sender: UIButton!){
let controler = UIAlertController(title:"Are you sure?",
message:nil,preferredStyle: .ActionSheet)
let yesAction = UIAlertAction(title:"Yes, I'm sure!",
style:.Destructive,handler:{ action in
let msg = self.nameField.text.isEmpty //这里 text 提示报错
（报错提示：value of optional type 'String?' not unwrapped;did you mean to use'!' or '?'?
?"You can breathe easy,everyting went ok."
:"You can breathe easy,\(self.nameField.text),"
+ " everything went ok."
let controller2 = UIAlertController(
title:"Something was Done",
message: msg,preferredStyle:.Alert)
let cancelAction = UIAlertAction(title:"Phew!",
style: .Cancel,handler:nil)
controller2.addAction(cancelAction)
self.presentViewController(controller2,animated:true,completion:nil)
})
let noAction = UIAlertAction(title:"no way!",style: .Cancel,handler:nil)
controler.addAction(yesAction)
controler.addAction(noAction)
if let ppc = controler.popoverPresentationController{
ppc.sourceView = sender
ppc.sourceRect = sender.bounds
}
presentViewController(controler, animated: true, completion: nil)
}
}

我觉得这本书有问题。在出错的那一行右边text改成text！

应该是不行的吧，获取为nil时会出错的

下面两只虫子哪只是公的，哪只是母的。驴绞尽脑汁，还是答不上来。牛骂道：真是头蠢驴，男左女右嘛。 ！