UI2_同步下载

//

//  ViewController.m

//  UI2_同步下载

//

//  Created by zhangxueming on 15/7/17.

//  Copyright (c) 2015年 zhangxueming. All rights reserved.

//



#import "ViewController.h"



//http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=页数



@interface ViewController ()

{

    NSURLConnection *_urlConnection;//苹果官方提供的, 给客户端与服务器建立连接

    NSMutableArray *_dataArray;    //提供数据

}

@end



//同步下载:当向服务器,发送网络请求后, 请求数据期间, UI不能交互,只有在服务器返回数据之后才能进行后续的操作

//请求的数据量比较小,特殊要求



@implementation ViewController



- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    [self loadDataWithPage:4];

}



- (void)loadDataWithPage:(NSInteger)page

{

    //创建URL对象

    NSString *urlString = [NSString stringWithFormat:@"http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=%ld", page];

    NSURL *url = [NSURL URLWithString:urlString];

    //创建数据请求对象

    //cachePolicy 缓存协议是个枚举类型：

    //NSURLRequestUseProtocolCachePolicy 基础策略

    //NSURLRequestReloadIgnoringLocalCacheData 忽略本地缓存

    //NSURLRequestReturnCacheDataElseLoad 首先使用缓存，如果没有本地缓存，才从原地址下载

    //NSURLRequestReturnCacheDataDontLoad 使用本地缓存，从不下载，如果本地没有缓存，则请求失败。此策略多用于离线操作

    //NSURLRequestReloadIgnoringLocalAndRemoteCacheData 无视任何的缓存策略，无论是本地还是远程，总是从原地址重新下载

    //NSURLRequestReloadRevalidatingCacheData 如果本地缓存是有效的则不下载。其他任何情况都从原地址重新下载

    NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10];

    //状态响应

    //404(请求失败)  200(请求成功) 400(客户端语法错误) 500(服务端错误)

    NSHTTPURLResponse *response= nil;

    NSError *error = nil;

    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

    

    //打印状态码

    NSLog(@"%@", response);

    NSLog(@"code = %li", response.statusCode);

    NSLog(@"header = %@",response.allHeaderFields);

    

    id result = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];

    

    NSLog(@"result= %@", result);

}



- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}



@end