Swift学习(传值)

从前一页面向后一页面传值一般用到属性(比较简单的传值方式),当需要从后一页面向前传值时,我们一般想到的是代理和block,当然还有单例,今天我们就学习用Swift如何传值

我们从最简单的属性传值开始,使用了StoryBoard

第一个页面

class AddressBookViewController: UITableViewController<span style="color:#3333FF;">, InfoDelegate</span> {

    var array = [AddressInfo]() //给定初始数据数组

<span style="color:#FF0000;">   //func getData(ntf:NSNotification) {
        self.array.append(ntf.object as AddressInfo)
    }</span>

    override func viewDidLoad() {
        super.viewDidLoad()

       // <span style="color:#FF0000;">NSNotificationCenter.defaultCenter().addObserver(self, selector:Selector("getData:"), name:"aaaa", object:nil)</span>

        var model1 : AddressInfo = AddressInfo()//AddressInfo继承于NSObject,有三个属性

        var dic = Dictionary<String, String>()

        dic["name"] = "小明"
        dic["age"] = "40"
        dic["phoneNumber"] = "1200001125"
        model1.setValuesForKeysWithDictionary(dic)

        self.array.append(model1)
     }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         return self.array.count
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as UITableViewCell
        var item = self.array[indexPath.row] as AddressInfo
        cell.textLabel.text = item.name
        return cell
    }
    // MARK: - Navigation

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        // Get the new view controller using [segue destinationViewController].
        // Pass the selected object to the new view controller.
        if sender is UITableViewCell {
            var cell = sender as UITableViewCell
            var indexPath = tableView.indexPathForCell(cell)
            var model = self.array[indexPath!.row]
            var vc = segue.destinationViewController as InfoViewController
<span style="color:#3333FF;">//            vc.delegate = self</span>
            vc.info = model //在接受方定义属性接收需要传递的值
        } else {
            var vc = segue.destinationViewController as InfoViewController
<pre name="code" class="plain"><span style="color:#3333FF;">//            vc.delegate = self</span>

} }

func addInfo(info : AddressInfo) {

self.array.append(info)

//       self.tableView.reloadData

}

}

后一页面

import UIKit

<span style="color:#000099;">// protocol InfoDelegate {
//    func addInfo(info: AddressInfo)
// }</span>

class InfoViewController: UIViewController {

    var info : AddressInfo?
 <span style="color:#000099;">
//    var delegate : protocol<InfoDelegate>?</span>

    @IBOutlet weak var nameTF: UITextField!

    @IBOutlet weak var addButton: UIButton!

    @IBAction func add(sender: AnyObject) {

        var model = AddressInfo()
        var dic = Dictionary<String, String>()
        dic["name"] = nameTF.text
        dic["age"] = ageTF.text
        dic["phoneNumber"] = phoneNumberTF.text
        model.setValuesForKeysWithDictionary(dic);

<span style="color:#FF0000;">        //NSNotificationCenter.defaultCenter().postNotificationName("aaaa", object: model, userInfo:dic)</span>

<span style="color:#000099;">//        self.delegate!.addInfo(model)</span>

        var alt = UIAlertView(title:"已添加", message:"已经将name:\(nameTF.text)插入", delegate: self, cancelButtonTitle:"OK")
        alt.show()
    }
    @IBOutlet weak var updateButton: UIButton!
    @IBAction func update(sender: AnyObject) {
    }
    @IBOutlet weak var phoneNumberTF: UITextField!
    @IBOutlet weak var ageTF: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        if info == nil {
     updateButton.enabled = false
        } else {
            nameTF.text = info!.name
            ageTF.text = info!.age
            phoneNumberTF.text = info!.phoneNumber
        }

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

好的,我们再说说代理,其实Swit中的代理和OC中的代理相差不大,我们一样要在后一页面制定协议,写在import UIKit之后

protocol InfoDelegate {

func addInfo(info: AddressInfo)

}

在viewDidLoad之前定义属性代理

在add方法中使用代理传值,

在第一个页面遵守代理,设置代理,完成代理方法,这样就实现了代理传值(蓝色代码)

还有一种方法释永信更广,不单单用于后一页面向前一页面传值,还能用于,后面的页面,中间隔着几个页面进行传值,实现代码更为简单,上面红色代码块就是此方法

最后简单说一下单例

import UIKit

class SingleData: NSObject {
    var name : String?

    class func defaultSingleData() -> SingleData {
        var once : dispatch_once_t = 0
        var singleData : SingleData?
        dispatch_once(&once, {
            singleData = SingleData()
        })
        return singleData!
    }

    //升级版本
    class func defaultSingleData1() -> SingleData {
        struct SSSingleData {
            static var once : dispatch_once_t = 0
            static var singleData : SingleData?
        }
        dispatch_once(&SSSingleData.once, {
            SSSingleData.singleData = SingleData()
        })
        return SSSingleData.singleData!
    }

 }

有兴趣的同学可以使用单例做个小练习