Question

我在stackoverflow＆amp;上非常新。非常非常新的Swift。我需要从PHP获得结果，使用如下的Swift代码：

func GetEtatO2()
{
    let url = NSURL(string: "http://www.exxagon.com/php/GetEtatO2.php")
    let task = NSURLSession.sharedSession().dataTaskWithURL(url!,
        completionHandler:
        {
            (data, response, error) -> Void in
            if error != nil
            {
                print("Error: \(error)")
                return
            }
            else
            {
                print("data ==> \(data)")
                print("response ==> \(response)")
                print("error ==> \(error)")
                let responseString = String(data: data!, encoding: NSUTF8StringEncoding)
                print("responseString ==> \(responseString!)")
                self.EtatO2 = responseString!
            }
        }
    )
    task.resume()
}

我的PHP代码返回的字符串是＆＃34; ON＆＃34; ou＆＃34; OFF＆＃34;。

我可以将此字符串作为我的代码的else部分，但是，行self.EtatO2 = responseString!似乎什么都不做;我的意思是价值＆＃34; ON＆＃34; ou＆＃34; OFF＆＃34;未存储在var EtatO2。

中

我确定我想念比我更大的东西......你能帮一些忙吗？非常感谢提前。

Answer 1

我终于找到了解决方案：插入

 dispatch_async(dispatch_get_main_queue(), { () -> Void in  ...
as follow
`@IBAction func GetEtatO2(sender: UIButton) {
    let Url = NSURL(string: "http://www.exxagon.com/php/GetEtatO2.php")
    let task = NSURLSession.sharedSession().dataTaskWithURL(Url!, completionHandler: { (data, response, error) -> Void in
            print( ">>>> Debut >>>>")
            print("Error: \(error)")
            if error != nil
            {
                return
            }
            else
            {
                print("data: \(data)")
                print("Response: \(response)")
                let responseString = String(data: data!, encoding: NSUTF8StringEncoding)
                print("responseString: \(responseString)")
                dispatch_async(dispatch_get_main_queue(), { () -> Void in
                    self.EtatO2Label.text = responseString
                })
            }
            print( "<<<< Fin <<<<")
    })
    task.resume()
  }

通过这种方式，按下GetEtatO2按钮，在标签中显示正确的状态。

Answer 2

确保在调用完成处理程序之后才尝试使用self.Etat02。一种方法是向GetEtat02()添加完成处理程序。

func GetEtatO2(completion:(String) -> ())
{
    let url = NSURL(string: "http://www.exxagon.com/php/GetEtatO2.php")
    let task = NSURLSession.sharedSession().dataTaskWithURL(url!,
        completionHandler:
        {
            (data, response, error) -> Void in
            if error != nil
            {
                completion("Error: \(error)")
            }
            else
            {
                let responseString = String(data: data!, encoding: NSUTF8StringEncoding)

                completion(responseString!)
            }
        }
    )
    task.resume()
}

然后您可以致电GetEtat02()并使用这样的回复：

GetEtatO2() { responseString in
    // This won't run until the NSURLSession completes
    print(responseString)
}

// responseString doesn't exist here, only in the closure above

用swift获取PHP输出

2 个答案: