https://github.com/linusling/differentwaystopassvalueswift
https://github.com/linusling/differentwaystopassvalueswift
Last synced: about 1 year ago
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- Host: GitHub
- URL: https://github.com/linusling/differentwaystopassvalueswift
- Owner: LinusLing
- License: mit
- Created: 2015-09-01T02:19:29.000Z (almost 11 years ago)
- Default Branch: master
- Last Pushed: 2015-09-30T01:55:57.000Z (over 10 years ago)
- Last Synced: 2025-03-22T06:41:42.696Z (about 1 year ago)
- Language: Swift
- Homepage:
- Size: 2.54 MB
- Stars: 7
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# DifferentWaysToPassValueSwift
这是一个工程，展示了如何在 VC 之间进行传值，包括正向传值、反向传值和无向传值。
* 本示例代码基于 Xcode 7 ，并使用Swift 2.0 写成。
## Demo
## 正向传值
RootVC:
```swift
let del:DelegateViewController = DelegateViewController()
del.positiveValue = title! // 正向传值
self.presentViewController(del, animated: true, completion: nil)
```
DelegateVC:
```swift
var positiveValue:String = String() // 正向传值，接收方
```
## 反向传值
反向传值包括 delegate 、闭包、KVO 和 Notification 四种种方式：
### Delegate
RootVC:
```swift
@IBAction func delegateButtonDidTapped(sender: AnyObject) {
...
del.delegate = self // 设置下一个VC的delegate为当前的rootVC
...
}
```
```swift
//实现delegate的方法
func passValue(str:String) {
self.delegateTF.text = str
}
```
DelegateVC:
```swift
var delegate:delegateOfNegative? //定义具体的delegate
```
```swift
func back(sender:UIButton) {
let tf:UITextField = self.view.viewWithTag(10000) as! UITextField
delegate?.passValue(tf.text!) // 调用delegate的传值方法passValue
self.dismissViewControllerAnimated(true, completion: nil)
}
```
### 闭包
RootVC:
```swift
@IBAction func blockButtonDidTapped(sender: AnyObject) {
...
let blo:BlockViewController = BlockViewController()
// 设置block中要传递的值的接收方式
blo.passBlockValue = {
(title:String) in
self.positiveTF.text = title
}
self.presentViewController(blo, animated: true, completion: nil)
}
```
BlockVC:
```swift
var passBlockValue:((title:String) -> Void)? // 定义block，包含参数title
```
```swift
func back(sender:UIButton) {
let tf:UITextField = self.view.viewWithTag(10001) as! UITextField
passBlockValue?(title:tf.text!) // 使用block传递title这个值
self.dismissViewControllerAnimated(true, completion: nil)
}
```
### KVO
KVO只要是监听的属性，不管是正向还是反向都会触发`observeValueForKeyPath`方法，在其中做相应的显示即可。
RootVC:
```swift
var kvc:KVOViewController = KVOViewController() // 全局的KVOvc方便在deinit时removeobserver
```
```swift
@IBAction func KVOButtonDidTapped(sender: AnyObject) {
kvc.k = kvo()
// addObserver添加监听
kvc.k.addObserver(self, forKeyPath: "title", options: [NSKeyValueObservingOptions.Old, NSKeyValueObservingOptions.New], context: nil)
kvc.k.title = self.positiveTF.text!
self.presentViewController(kvc, animated: true, completion: nil)
}
```
```swift
// 监听对象的属性或者实例变量发生变化，就自动调用该函数，执行相应操作
override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer) {
if keyPath == "title" {
print(change!)
var nv = change!
let newvalue: AnyObject? = nv["new"]
print("the new value is \(newvalue!)")
self.positiveTF.text = "\(newvalue!)" // 将监听到的变化值赋值给TF来显示
}
}
deinit {
// removeObserver移除监听
// add和remove必须对应，否则报错
kvc.k.removeObserver(self, forKeyPath: "title", context: nil)
}
```
KVOVC:
```swift
//要监听的对象的定义
class kvo: NSObject {
var ptitle : String = ""
// dynamic修饰的即为可支持KVO
dynamic var title : String {
get {
return self.ptitle
}
set {
self.ptitle = newValue
}
}
override init() {
println("init")
}
deinit {
println("deinit")
}
}
```
```swift
func back(sender:UIButton) {
let tit = (self.view.viewWithTag(10003) as! UITextField).text
k.title = tit! // 对监听的属性赋值会触发observeValueForKeyPath方法
self.dismissViewControllerAnimated(true, completion: nil)
}
```
### Notification
RootVC:
viewDidLoad:
```swift
// 注册一个通知
NSNotificationCenter.defaultCenter().addObserver(self, selector: "notifReceive:", name: "notifName", object: nil)
```
```swift
@IBAction func NotificationButtonDidTapped(sender: AnyObject) {
let noti:NotificationViewController = NotificationViewController()
noti.positiveValue = self.positiveTF.text!
self.presentViewController(noti, animated: true, completion: nil)
}
// 每次调用对应name的postNotificationName方法会由selector处理
func notifReceive(notification:NSNotification) {
self.positiveTF.text = "\(notification.object!)"
print("notif : \(notification.name), \(notification.object!)")
}
deinit {
...
// removeObserver移除对应name的通知
NSNotificationCenter.defaultCenter().removeObserver(self, name: "notifName", object: nil)
}
```
NotificationVC:
```swift
func back(sender:UIButton) {
let tit = (self.view.viewWithTag(10004) as! UITextField).text
// 发送一个通知，name要对应。单一数据可用object传，多个数据可以用dictionary放进userInfo传
NSNotificationCenter.defaultCenter().postNotificationName("notifName", object: tit, userInfo: nil)
self.dismissViewControllerAnimated(true, completion: nil)
}
```
## 无向传值
其实就是利用`NSUserDefaults`来存取数据，哈哈。
## PS
* 所谓“反向传值”只是在业务逻辑上是从第二个 VC 回到第一个 VC 的过程中传值。并不是说列出的几种传值方式只能在反向情况下使用。
* 特别感谢 [@靛青K](http://weibo.com/2314535081) 给我提出的宝贵意见或建议 :]