NSURLConnection初体验(加载网络数据)

先来看一下效果图

展示加载成功界面

if (connectionError) {失败后

//  Created by 贺培勇 on 16/7/9.

//  Copyright © 2016年 tcast. All rights reserved.

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

//创建URL

NSURL * url = [NSURL URLWithString:@"http://www.sina.com.cn/"];

//根据URL创建请求

NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:5];

//设置请头属性

[request setValue:@"iPhone AppleWebKit" forHTTPHeaderField:@"User-Agent"];

__weak typeof(self) weakself = self;

//连立连接,发送请求

#pragma clang diagnostic push

#pragma clang diagnostic ignored "-Wdeprecated-declarations"

//将编译器提示-Wdeprecated-declarations警告的代码放在这里即可

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {

if (connectionError) {

UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"网络连接失败" message:@"是否重新加载" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];

[alertView show];

return;

}

if (data == nil) {

UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"获取网络数据失败" message:nil delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];

[alertView show];

return;

}

//数据分析/数据反序列化

NSString * restre = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

//把数据显示到界面上

UIWebView * webView = [[UIWebView alloc]init];

webView.frame = weakself.view.bounds;

[weakself.view addSubview:webView];

//加载超文本数据并显示到UIWebView

[webView loadHTMLString:restre baseURL:url];

#pragma clang diagnostic pop

}];

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

@end