本文介绍了Swift中四种常见的传值方法：属性传值（正向传递）、Block（代码块）反向传值、代理反向传值以及通知中心和单例传值。通过具体的代码示例，详细阐述了如何在不同场景下实现视图控制器间的值传递，对于熟悉Objective-C的开发者来说，Swift的这些特性提供了平滑的过渡路径。
传值:在此之前我们先定义两个视图控制器ViewController ViewController01
1.属性传值正向、这里以字符串做例子、其他类型类似:ViewController->>>ViewController01
ViewController:
let vc = ViewController01()
vc.str ="hello"
self.navigationController?.pushViewController(vc, animated:true)
ViewController01:
class ViewController01: UIViewController {
var str =NSString()
overridefunc viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor =UIColor.white
print(self.str)
}
overridefunc didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
2.代码块反向传值
ViewController:
func click() {
let vc =ViewController01()
vc.callBlock{(value: String?) ->Void in
print(value)
}
self.navigationController?.pushViewController(vc, animated:true)
}
ViewController01:
首先定义代码块类型:typealias textBlock = (String)->()
然后定义代码块属性:var block:textBlock?
实现代码块
func callBlock(block:textBlock?) {
self.block = block
}
func click() {
if let block = self.block {
block("li01")
}
self.navigationController?.popToRootViewController(animated:true)
}
3.delegate反向传值(协议)
ViewController:首先要继承ViewController01中的协议giveFirstStrDelegate
func click() {
let vc =ViewController01()
vc.delegate = self
self.navigationController?.pushViewController(vc, animated:true)
}
代理方法
func giveStr(controller: ViewController01, string: String) {
print(string)
}
ViewController01:
首先定义个协议
protocol giveFirstStrDelegate:NSObjectProtocol {
func giveStr(controller:ViewController01,string:String)
}
var delegate:giveFirstStrDelegate?
这些类似与OC中的代理实现
func click() {
if((delegate) !=nil){
delegate?.giveStr(controller:self,string:"hi I am li")
}
self.navigationController?.popToRootViewController(animated:true)
}
4.通知中心传值参考OC
5.单列传值也同样参考OC
基本是写过OC的swift都可以很容易上手
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