Swift中界面传值的方法 主要有三种
1.代理传值
2.闭包传值(即OC中的Block)
- 属性传值
代理传值
First页面
class FirstViewController: UIViewController ,ValueDelegate {
//设置属性label 后面加个! 代表在需要的时候再初始化
var label : UILabel!
override func viewDidLoad() {
super.viewDidLoad()
//设置导航视图控制器的右边按钮
//在Swift中设置枚举值时候使用的是枚举类名 + . 枚举名 在这里系统帮我们自动省略掉类名
//在设置事件的时候 ("方法名")
self.navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Add, target: self, action: "jumpToSecondVCClick")
//初始化label的位置
label = UILabel(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
//设置label的背景颜色
label.backgroundColor = UIColor.cyanColor()
//将label添加到视图上
self.view.addSubview(label)
}
//声明导航视图控制器的按钮 点击事件
func jumpToSecondVCClick() {
let secondVC = SecondViewController()
//设置代理
secondVC.delegate = self
//跳转到第二个页面
self.showViewController(secondVC, sender: nil)
}
//实现代理方法
func valueClicked(string: String) {
label.text = string
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
Second页面
//声明协议 同OC相同 还是需要写到类的上面
protocol ValueDelegate {
//声明代理方法
func valueClicked(string : String)
}
class SecondViewController: UIViewController {
//设置代理属性 必须置为nil
var delegate : ValueDelegate? = nil
//设置输入框属性
var TF : UITextField!
override func viewDidLoad() {
super.viewDidLoad()
//设置页面的颜色
self.view.backgroundColor = UIColor.whiteColor()
//设置导航视图控制器的左边按钮
self.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Cancel, target: self, action: "jumpToFristVCClick")
//初始化输入框并设置frame
TF = UITextField(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
TF.backgroundColor = UIColor.cyanColor()
//将输入框添加到视图上
self.view.addSubview(TF)
}
//设置跳转时间
func jumpToFristVCClick() {
//当跳转到Frist页面的时候 设置代理将输入款输入的文字传到First页面
self.delegate?.valueClicked(TF.text!)
//跳转到First页面
self.navigationController?.popViewControllerAnimated(true)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
闭包传值
关于UI的代码与上面的一模一样 只是传值的方式不一样,在下面就不添加过多的注释了
First页面
class FirstViewController: UIViewController{
var label : UILabel!
override func viewDidLoad() {
super.viewDidLoad()
self.navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Add, target: self, action: "jumpToSecondVCClick")
label = UILabel(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
label.backgroundColor = UIColor.cyanColor()
self.view.addSubview(label)
}
func jumpToSecondVCClick() {
let secondVC = SecondViewController()
//将传过来的值 赋给label
secondVC.sendValueClsure = { (string : String) -> Void in
self.label.text = string
}
self.showViewController(secondVC, sender: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
Second页面
//重命名一个闭包
typealias sendValue = (string : String) -> Void
class SecondViewController: UIViewController {
//创建一个闭包属性
var sendValueClsure : sendValue?
var TF : UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = UIColor.whiteColor()
self.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Cancel, target: self, action: "jumpToFristVCClick")
TF = UITextField(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
TF.backgroundColor = UIColor.cyanColor()
self.view.addSubview(TF)
}
func jumpToFristVCClick() {
//将值附在闭包上,传到First页面
self.sendValueClsure!(string: TF.text!)
self.navigationController?.popViewControllerAnimated(true)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
属性传值
UI与上两个基本一样,将First页面的UILabel换成UITextField 即可
Frist页面
class FirstViewController: UIViewController{
var TF : UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Add, target: self, action: "jumpToSecondVCClick")
TF = UITextField(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
TF.backgroundColor = UIColor.cyanColor()
self.view.addSubview(TF)
}
func jumpToSecondVCClick() {
let secondVC = SecondViewController()
//将输入框中输入的文字赋值给Second控制器的属性string
secondVC.string = TF.text
self.showViewController(secondVC, sender: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
Second页面
class SecondViewController: UIViewController {
var string : String? = nil
var TF : UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = UIColor.whiteColor()
self.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Cancel, target: self, action: "jumpToFristVCClick")
TF = UITextField(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
TF.backgroundColor = UIColor.cyanColor()
//将从First页面传回来的string的值赋给Second的TF
TF.text = string
self.view.addSubview(TF)
}
func jumpToFristVCClick() {
self.navigationController?.popViewControllerAnimated(true)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
在这三天的Swift学习中 ,我发现 在使用时 ,其实大部分用到了OC中的方法和思想,只是Swift相比OC的代码格式上更加简洁和易记
由此可见,如果有OC基础的学习者们,在学习Swift的时候,只需要研究下Swift和OC的格式区别对于上手Swift还是相当快的
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