ios - swift通过属性传值,返回为空,怎么解决?

Question

新手敲代码,想从一个页面通过点击按钮往另外一个页面传值,通过属性传值的方式传递两个string,但是在第二个页面获取传到的值得时候,发现是空的,怎么解决?求教各位.

第一个页面:

func pushView(){

    
    let secondVC = secondViewController()
    
    secondVC.titleGo = "百度一下"

    secondVC.address = "https://www.baidu.com"
    
    
    self.performSegue(withIdentifier: "secondViewController", sender: self)
    
    print("======")
    
}

第二个页面:

class secondViewController: UIViewController {

@IBOutlet weak var itemBar: UINavigationItem!

var netAddress = String()

var address = String()

var titleGo = String()

var webView = WKWebView()

override func viewDidLoad() {
    
    
    itemBar.title = titleGo
    
    print("======+\(titleGo)")
    
    netAddress = address
    
    print("++++++=\(address)")
}

Answer 1

你 secondVC 是一局部變數…

performSegue 后，会有 prepare(for segue: UIStoryboardSegue, sender: Any?) 這個步驟。在這裡，可以取得到 segue 的 identifier, destination。

拿到 destination 後，修改 destination 內的屬性即可。

簡單的例子：

    @IBAction func btn1Pressed(_ sender: Any) {

        performSegue(withIdentifier: "segue1", sender: self)
    }

    @IBAction func btn2Pressed(_ sender: Any) {
        performSegue(withIdentifier: "segue2", sender: self)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "segue1" {
            if let target = segue.destination as? ViewController1 {
                target.text = "segue1"
                target.num = 1
            }
        } else if segue.identifier == "segue2" {
            if let target = segue.destination as? ViewController2 {
                target.text = "segue2"
                target.num = 2
            }
        }
    }

如果你想自己建立 ViewController 並且 push ，可以用 navigationController 的 push 或者用 viewController 的 present ：

    func test() {
        let vc = ViewController1()
        vc.text = "111"
        vc.num = 3

        // 这样显示 
        // in navigation controller
        self.navigationController?.pushViewController(vc, animated: true)
        
        // 或者这样
        // present modal viewController
        //self.present(vc, animated: true, completion: nil)
    }