如何使用闭包在两个ViewController之间传递数据 [英] How to pass data between two ViewController using closure

问题描述

我想知道如何使用闭包传递数据。我知道数据传递方法有三种：

I want to know how to pass data using closure. I know that there are three types of data pass approaches:

• 委托

• delegate

通知中心

关闭

我想用一个例子来适当地说明闭包。

I want proper clarification of closure with an example.

推荐答案

很好地传递带有块/闭包的数据并且合理的方法，比通知更好。
下面是相同的代码。

Well passing data with blocks / closures is a good and reasonable approach and much better than notifications. Below is the same code for it.

第一个ViewController（在其中创建第二个ViewController的对象）

 @IBAction func push(sender: UIButton) {
        let v2Obj = storyboard?.instantiateViewControllerWithIdentifier("v2ViewController") as! v2ViewController
        
        v2Obj.completionBlock = {[weak self] dataReturned in
            //Data is returned **Do anything with it **
            print(dataReturned)
        }
        navigationController?.pushViewController(v2Obj, animated: true)
        
    }

第二个ViewController（将数据传递回First VC）

import UIKit
typealias v2CB = (infoToReturn :String) ->()
class v2ViewController: UIViewController {
        var completionBlock:v2CB?
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    func returnFirstValue(sender: UIButton) {
        guard let cb = completionBlock else {return}
        cb(infoToReturn: "any value")
    }
    
}

这篇关于如何使用闭包在两个ViewController之间传递数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！