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 = [NSURL URLWithString:urlString];
//step2:实例化一个request
NSURLRequest * request = [NSURLRequestrequestWithURL:url cachePolicy: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 = [data length];
NSLog(@"返回数据量：%d",datalength);
[self.data appendData:data];
}
//获取文件地址
-(NSString *)dataFilePath:(NSString*)fileName
{
NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *document=[paths objectAtIndex:0];
return [document stringByAppendingPathComponent:fileName];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// //连接结束
NSLog(@"%d",[self.data length]);
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:[self dataFilePath:@"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"}}