码迷,mamicode.com
首页 > 移动开发 > 详细

iOS网络编程

时间:2015-03-05 13:04:01      阅读:254      评论:0      收藏:0      [点我收藏+]

标签:

         ios网络编程(http、socket)

分类: OS-X/iOS开发 7369人阅读 评论(3) 收藏 举报

目录(?)[+]

http编程综述:亦可称为soap编程。通常情况下,http编程要比socket编程相对要简单易用得多。所以用的最广广泛。

一、http编程其实就是http请求。http请求最长用的方法是 get 和 post 方法。
==》get方法和post方法相比理解起来比较简单,get方法可以直接请求一个url,也可以url后面拼接上参数作为一个新的url地址进行请求。get方法后面的value要经过unicode编码。form的enctype属性默认为application/x-www-form-urlencoded。不能发送二进制文件。
==》post方法相对要复杂一些。首先post方法要设置key和value ,所有的key和value都会拼接成 key1=value1&key2=value2的样式的字符串,然后这个字符串转化为二进制放到 http请求的body中。当请求发送的时候,也就跟随body一起传给服务器。http请求Content-Type设置为:application/x-www-form-urlencoded。这里讲的只是简单的post请求,一般发送文件不会选择这种方式(从技术方面考虑也可以发送文件,就是把文件以 key 和 value的方式放入)。下面我们再讨论一下post发送二进制文件更加普遍的方法。

二、HTTP协议是什么?
简单来说,就是一个基于应用层的通信规范:双方要进行通信,大家都要遵守一个规范,这个规范就是HTTP协议。
HTTP协议能做什么?
很多人首先一定会想到:浏览网页。没错,浏览网页是HTTP的主要应用,但是这并不代表HTTP就只能应用于网页的浏览。HTTP是一种协议,只要通信的双方都遵守这个协议,HTTP就能有用武之地。比如咱们常用的QQ,迅雷这些软件,都会使用HTTP协议(还包括其他的协议)。
HTTP协议如何工作?
大家都知道一般的通信流程:首先客户端发送一个请求(request)给服务器,服务器在接收到这个请求后将生成一个响应(response)返回给客户端。
在这个通信的过程中HTTP协议在以下4个方面做了规定:
1.         Request和Response的格式()
2.         建立连接的方式(1、非持久连接 2、持久连接)
3.         缓存的机制
4.         响应授权激发机制
(应用场合)
5.        基于HTTP的应用(1、 HTTP代理 2、多线程下载 3、 HTTPS传输协议原理 4、开发web程序时常用的Request Methods 5、用户与服务器的交互)


常用cocoa内部类: 
1,Reachability.h 苹果demo支持网络连接诊断
2,NSConnection连接、NSMutableURLRequest URL网址的请求封装包
3,NSXMLParser XML解析

常用第三方库:
1,ASIHttprequest 库

操作步骤:
1:检查网络环境(3G/WIFI)
2:发起NSConnection请求
3:处理返回xml数据包(NSXMLParser解析xml文件),或者返回文件png、pdf之类
4:若返回数据包中含有待下载的图片下载地址。则重复2、3步骤下载下来图片。只不过3中返回的是文件。

socket编程综述:
常用cocoa内部类:
常用第三方库:1,Asyncsocket库
操作步骤:



http网络编程实例   

一:确认网络环境3G/WIFI 
 
    1. 添加源文件和framework 
     
    开发Web等网络应用程序的时候,需要确认网络环境,连接情况等信息。如果没有处理它们,是不会通过Apple的审查的。 
    Apple 的 例程 Reachability 中介绍了取得/检测网络状态的方法。要在应用程序程序中使用Reachability,首先要完成如下两部: 
     
    1.1. 添加源文件: 
    在你的程序中使用 Reachability 只须将该例程中的 Reachability.h 和 Reachability.m 拷贝到你的工程中。如下图: 
 
     
     
    1.2.添加framework: 
    将SystemConfiguration.framework 添加进工程。如下图: 
     
     
    2. 网络状态 
     
    Reachability.h中定义了三种网络状态: 
    typedef enum { 
        NotReachable = 0,            //无连接 
        ReachableViaWiFi,            //使用3G/GPRS网络 
        ReachableViaWWAN            //使用WiFi网络 
    } NetworkStatus; 
     
    因此可以这样检查网络状态: 
 
    Reachability *r = [Reachability reachabilityWithHostName:@“www.apple.com”]; 
    switch ([r currentReachabilityStatus]) { 
            case NotReachable: 
                    // 没有网络连接 
                    break; 
            case ReachableViaWWAN: 
                    // 使用3G网络 
                    break; 
            case ReachableViaWiFi: 
                    // 使用WiFi网络 
                    break; 
    } 
     
    3.检查当前网络环境 
    程序启动时,如果想检测可用的网络环境,可以像这样 
    // 是否wifi 
    + (BOOL) IsEnableWIFI { 
        return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable); 
    } 
 
    // 是否3G 
    + (BOOL) IsEnable3G { 
        return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] != NotReachable); 
    } 
    例子: 
    - (void)viewWillAppear:(BOOL)animated {     
    if (([Reachability reachabilityForInternetConnection].currentReachabilityStatus == NotReachable) &&  
            ([Reachability reachabilityForLocalWiFi].currentReachabilityStatus == NotReachable)) { 
            self.navigationItem.hidesBackButton = YES; 
            [self.navigationItem setLeftBarButtonItem:nil animated:NO]; 
        } 
    } 
 
    4. 链接状态的实时通知 
    网络连接状态的实时检查,通知在网络应用中也是十分必要的。接续状态发生变化时,需要及时地通知用户: 
     
    Reachability 1.5版本 
    // My.AppDelegate.h 
    #import "Reachability.h" 
 
    @interface MyAppDelegate : NSObject <UIApplicationDelegate> { 
        NetworkStatus remoteHostStatus; 
    } 
 
    @property NetworkStatus remoteHostStatus; 
 
    @end 
 
    // My.AppDelegate.m 
    #import "MyAppDelegate.h" 
 
    @implementation MyAppDelegate 
    @synthesize remoteHostStatus; 
 
    // 更新网络状态 
    - (void)updateStatus { 
        self.remoteHostStatus = [[Reachability sharedReachability] remoteHostStatus]; 
    } 
 
    // 通知网络状态 
    - (void)reachabilityChanged:(NSNotification *)note { 
        [self updateStatus]; 
        if (self.remoteHostStatus == NotReachable) { 
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"AppName", nil) 
                         message:NSLocalizedString (@"NotReachable", nil) 
                        delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil]; 
            [alert show]; 
            [alert release]; 
        } 
    } 
 
    // 程序启动器,启动网络监视 
    - (void)applicationDidFinishLaunching:(UIApplication *)application { 
     
        // 设置网络检测的站点 
        [[Reachability sharedReachability] setHostName:@"www.apple.com"]; 
        [[Reachability sharedReachability] setNetworkStatusNotificati*****Enabled:YES]; 
        // 设置网络状态变化时的通知函数 
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:) 
                                                 name:@"kNetworkReachabilityChangedNotification" object:nil]; 
        [self updateStatus]; 
    } 
 
    - (void)dealloc { 
        // 删除通知对象 
        [[NSNotificationCenter defaultCenter] removeObserver:self]; 
        [window release]; 
        [super dealloc]; 
    }  
     
    Reachability 2.0版本 
     
 
    // MyAppDelegate.h 
    @class Reachability; 
 
        @interface MyAppDelegate : NSObject <UIApplicationDelegate> { 
            Reachability  *hostReach; 
        } 
 
    @end 
 
    // MyAppDelegate.m 
    - (void)reachabilityChanged:(NSNotification *)note { 
        Reachability* curReach = [note object]; 
        NSParameterAssert([curReach isKindOfClass: [Reachability class]]); 
        NetworkStatus status = [curReach currentReachabilityStatus]; 
     
        if (status == NotReachable) { 
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"AppName"" 
                              message:@"NotReachable" 
                              delegate:nil 
                              cancelButtonTitle:@"YES" otherButtonTitles:nil]; 
                              [alert show]; 
                              [alert release]; 
        } 
    } 
                               
    - (void)applicationDidFinishLaunching:(UIApplication *)application { 
        // ... 
                   
        // 监测网络情况 
        [[NSNotificationCenter defaultCenter] addObserver:self 
                              selector:@selector(reachabilityChanged:) 
                              name: kReachabilityChangedNotification 
                              object: nil]; 
        hostReach = [[Reachability reachabilityWithHostName:@"www.google.com"] retain]; 
        hostReach startNotifer]; 
        // ... 
    } 
 
 
二:使用NSConnection下载数据 
     
    1.创建NSConnection对象,设置委托对象 
     
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[self urlString]]]; 
    [NSURLConnection connectionWithRequest:request delegate:self]; 
     
    2. NSURLConnection delegate委托方法 
        - (void)connection:(NSURLConnection *)connection didReceiveResp*****e:(NSURLResp*****e *)resp*****e;   
        - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;   
        - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;   
        - (void)connectionDidFinishLoading:(NSURLConnection *)connection;   
 
    3. 实现委托方法 
    - (void)connection:(NSURLConnection *)connection didReceiveResp*****e:(NSURLResp*****e *)resp*****e { 
        // store data 
        [self.receivedData setLength:0];            //通常在这里先清空接受数据的缓存 
    } 
     
    - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { 
           /* appends the new data to the received data */ 
        [self.receivedData appendData:data];        //可能多次收到数据,把新的数据添加在现有数据最后 
    } 
 
    - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { 
        // 错误处理 
    } 
 
    - (void)connectionDidFinishLoading:(NSURLConnection *)connection { 
        // disconnect 
        [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;    
        NSString *returnString = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding]; 
        NSLog(returnString); 
        [self urlLoaded:[self urlString] data:self.receivedData]; 
        firstTimeDownloaded = YES; 
    } 
 
三:使用NSXMLParser解析xml文件 
 
    1. 设置委托对象,开始解析 
    NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];   //或者也可以使用initWithContentsOfURL直接下载文件,但是有一个原因不这么做: 
    // It‘s also possible to have NSXMLParser download the data, by passing it a URL, but this is not desirable 
    // because it gives less control over the network, particularly in responding to connection errors. 
    [parser setDelegate:self]; 
    [parser parse]; 
 
    2. 常用的委托方法 
    - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName  
                                namespaceURI:(NSString *)namespaceURI 
                                qualifiedName:(NSString *)qName  
                                attributes:(NSDictionary *)attributeDict; 
    - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName  
                                namespaceURI:(NSString *)namespaceURI  
                                qualifiedName:(NSString *)qName; 
    - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string; 
    - (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError; 
 
    static NSString *feedURLString = @"http://www.yifeiyang.net/test/test.xml"; 
 
    3.  应用举例 
    - (void)parseXMLFileAtURL:(NSURL *)URL parseError:(NSError **)error 
    { 
        NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:URL]; 
        [parser setDelegate:self]; 
        [parser setShouldProcessNamespaces:NO]; 
        [parser setShouldReportNamespacePrefixes:NO]; 
        [parser setShouldResolveExternalEntities:NO]; 
        [parser parse]; 
        NSError *parseError = [parser parserError]; 
        if (parseError && error) { 
            *error = parseError; 
        } 
        [parser release]; 
    } 
 
    - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI  
                                        qualifiedName:(NSString*)qName attributes:(NSDictionary *)attributeDict{ 
        // 元素开始句柄 
        if (qName) { 
            elementName = qName; 
        } 
        if ([elementName isEqualToString:@"user"]) { 
            // 输出属性值 
            NSLog(@"Name is %@ , Age is %@", [attributeDict objectForKey:@"name"], [attributeDict objectForKey:@"age"]); 
        } 
    } 
 
    - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI  
                                        qualifiedName:(NSString *)qName 
    { 
        // 元素终了句柄 
        if (qName) { 
               elementName = qName; 
        } 
    } 
 
    - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string 
    { 
        // 取得元素的text 
    } 
 
    NSError *parseError = nil; 
    [self parseXMLFileAtURL:[NSURL URLWithString:feedURLString] parseError:&parseError]; 

//实例
//
//  NLViewController.m
//  NetWorkTest
//
//  Created by Nono on 12-5-16.
//  Copyright (c) 2012年 NonoWithLilith. All rights reserved.
//
#import "NLViewController.h"

@interface NLViewController ()

@end

@implementation NLViewController
@synthesize label = _label;
@synthesize data = _data;
@synthesize connection = _connection;
- (void)dealloc{
    [self.label release];
    [self.data release];
    [super dealloc];
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10.0, 10.0, 300.0, 400)];
    self.label = label;
    label.textAlignment = UITextAlignmentCenter;
    [label setNumberOfLines:0];
    label.lineBreakMode = UILineBreakModeWordWrap; 
    self.label.text = @"正在在请求数据";
    [self.view addSubview:label];
    [label release];
    //step 1:请求地址
    NSString *urlString = @"http://www.google.com";
    NSURL *url = [NSURL URLWithString:urlString];
    //step 2:实例化一个request
    NSURLRequest *requrst = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30.0];
    //step 3:创建链接
    self.connection = [[NSURLConnection alloc] initWithRequest:requrst delegate:self];
    if ( self.connection) {
        NSLog(@"链接成功");
    }else {
        NSLog(@"链接失败");
    }
    
    [url release];
    [urlString release];
    [requrst release];
// Do any additional setup after loading the view, typically from a nib.
}

- (void)viewDidUnload
{
    self.label = nil;
    self.data = nil;
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

#pragma mark-
#pragma NSUrlConnectionDelegate methods
- (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 textEncodingName]); 
    NSMutableData *d = [[NSMutableData alloc] init];
     self.data = d;
    [d release];
}

- (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
    
    NSUInteger datalength = [data length];
    NSLog(@"返回数据量:%d",datalength);
    [self.data appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    //连接结束
    
    NSLog(@"%d:",[self.data length]);
    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
    NSString *mystr = [[NSString alloc] initWithData:_data encoding:enc];
   // string i
    NSLog(@"最后的结果:%@",mystr);
    self.label.text = mystr;
    [mystr release];
    [self.connection release];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    //链接错误
}

@end

iOS网络编程

标签:

原文地址:http://blog.csdn.net/zhaoguodongios/article/details/44079413

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!