Xcode9学习笔记74

    var label = UILabel()//给当前视图控制器类添加一个标签属性，该标签对象用来显示远程服务器返回的信息

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        label.frame = CGRect(x: 20, y: 40,  280, height: 500)
        label.text = "Loading..."//默认文字内容
        label.font = UIFont(name: "Arial", size: 12)
        label.backgroundColor = UIColor.lightGray
        label.numberOfLines = 0//0表示不限制标签对象的行数
        label.lineBreakMode = NSLineBreakMode.byWordWrapping
        self.view.addSubview(label)
        
        let url = URL(string: "http://www.weather.com.cn/data/sk/101010100.html")
        
        let request = URLRequest.init(url: url!, cachePolicy: URLRequest.CachePolicy.useProtocolCachePolicy, timeoutInterval: 30)//第2个参数为网络请求的缓存协议
        
        do {
            var response:URLResponse?//创建一个网络返回对象
            //利用网络连接对象实现网络的通信，网络连接创建成功后，就创建了一个网络连接，并将返回结果存储为一个二进制数据对象
            let data:Data? = try NSURLConnection.sendSynchronousRequest(request, returning: &response)
            //将数据对象转化成字符串对象并采用指定的编码方式
            let str = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
            self.label.text = str! as String
        } catch {
            print("Network error.")
        }
    }