如何通过viewView保存访问过的页面？和如何获取并解析服务器端发送过来的json数据？通过一个简单的Demo来学习一下吧！

操作步骤：

1.创建SingleViewApplication应用，新建VIewController，并在xib试图中添加WebView，继承webview的Delegate协议。

2.将ViewController类遵循UIWebViewDelegate和NSURLConnectionDataDelegate协议，并且实现协议中的方法。

ViewController.h：

#import <UIKit/UIKit.h>  @interface ViewController : UIViewController<UIWebViewDelegate,NSURLConnectionDataDelegate> @property (retain, nonatomic) IBOutlet UIWebView *webview; @property (retain, nonatomic) UIAlertView * alert; @property (retain, nonatomic) IBOutlet UITextField *searchText; - (IBAction)searchClick:(id)sender;   @property (retain, nonatomic) IBOutlet UILabel *label; @property (retain, nonatomic) NSURLConnection * connection; @property (retain, nonatomic) NSMutableData * data; @end

VIewController.m:

#import "ViewController.h"

@interfaceViewController ()

@end

@implementation ViewController

- (void)viewDidLoad

{

    [superviewDidLoad];

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

    //请求网络页面

//    NSURL * url = [NSURL URLWithString:@"http://www.taobao.com"];   //一定要加http://

//    NSURLRequest * request = [NSURLRequest requestWithURL:url];

//    [self.webview loadRequest:request];

//

//

//    //html加载本地网页

//    NSString * str = [[NSBundle mainBundle] pathForResource:@"百度图片—全球最大中文图片库" ofType:@"html"];

//    str = [NSString stringWithContentsOfFile:str encoding:NSUTF8StringEncoding error:nil];

//    NSLog(@"%@",str);

//    [self.webview loadHTMLString:str baseURL:[[NSBundle mainBundle]bundleURL]];

//

self.label.text =@"正在请求数据";

    //step1:请求地址

    //保存页面

    //NSString * urlString = @"http://www.baidu.com";

   //访问服务器获取json数据

    NSString * urlString =@"http://www.weather.com.cn/data/cityinfo/101020100.html";

NSURL * url = [NSURLURLWithString:urlString];

    //step2:实例化一个request

    NSURLRequest * request = [NSURLRequestrequestWithURL:urlcachePolicy:NSURLRequestUseProtocolCachePolicytimeoutInterval:30.0];

    //step3:创建链接

    self.connection = [[NSURLConnectionalloc]initWithRequest:request delegate:self];

    if(self.connection)

{

NSLog(@"创建链接成功");

}else{

NSLog(@"创建链接失败");

}

[url release];

[urlString release];

}


- (void)didReceiveMemoryWarning

{

    [superdidReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}


- (void)dealloc {

[_webview release];

    [_searchTextrelease];

[_label release];

[super dealloc];

}

//获取数据

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response

{

    //接受一个服务端回话，再次一般初始化接受数据的对象

    //NSLog(@"返回数据类型%@",[response ]);

    //NSLog(@"返回数据编码%@",[response text]);

    NSMutableData * data = [[NSMutableDataalloc]init];

self.data = data;

[data release];

}

//不断的获取数据

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

{

    //接受返回数据，这个方法可能会被调用多次，因此将多次返回数据加起来

NSInteger datalength = [datalength];

NSLog(@"返回数据量：%d",datalength);

[self.dataappendData:data];

}

//获取文件地址

-(NSString *)dataFilePath:(NSString*)fileName

{

    NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);

NSString *document=[pathsobjectAtIndex:0];

    return [documentstringByAppendingPathComponent:fileName];

}


-(void)connectionDidFinishLoading:(NSURLConnection *)connection

{

//    //连接结束

NSLog(@"%d",[self.datalength]);

self.label.text =@"请求结束";

    //可以下载图片

    //[self.data writeToFile:[self dataFilePath:@"image.jpg"] atomically:YES];

    NSString * mystr = [[NSStringalloc]initWithData:self.dataencoding:NSUTF8StringEncoding];

[mystr writeToFile:[selfdataFilePath:@"百度图片—全球最大中文图片库.html"] atomically:YES encoding:NSUTF8StringEncoding error:nil];

    NSLog(@"最后的结果%@",mystr);

[mystr release];

//    NSDictionary *weather = [NSJSONSerialization JSONObjectWithData:self.data options:NSJSONReadingMutableContainers  error:nil];

//    NSLog(@"%@",weather);

//    [weather writeToFile:[self dataFilePath:@"weather.plist"] atomically:YES];

}


-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error

{

self.label.text =@"连接失败";

}

- (IBAction)searchClick:(id)sender {

}

@end


结果：

2013-08-27 16:09:18.821 WebViewDemo[673:c07] 创建链接成功

2013-08-27 16:09:19.161 WebViewDemo[673:c07] 返回数据量：153

2013-08-27 16:09:19.161 WebViewDemo[673:c07] 153

2013-08-27 16:09:19.193 WebViewDemo[673:c07] 最后的结果{"weatherinfo":{"city":"上海","cityid":"101020100","temp1":"32℃","temp2":"27℃","weather":"多云","img1":"d1.gif","img2":"n1.gif","ptime":"11:00"}}



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