iPhone开发【十九】XML解析之NSXMLParser（使用Web Services查询火车信息）

转载请注明出处，原文网址：http://blog.csdn.net/m_changgong/article/details/8246333 作者：张燕广

实现的功能：1）根据火车车次查询火车信息；2）演示XML解析类NSXMLParser的应用。

关键词：NSXMLParser XML解析

1、新建一个Sigle View Application，命名为Train，工程结构如下：

2、修改ViewController.xib，添加一个TextField控件和一个Button。

3、修改ViewController.h，如下：

 #import <UIKit/UIKit.h>

 @interface ViewController : UIViewController<NSXMLParserDelegate, NSURLConnectionDelegate> {
     bool elementFound;
     uint count;
 }

 @property(strong,nonatomic)NSURLConnection *conn;
 @property(strong,nonatomic)NSString *soapMessage;
 @property(strong,nonatomic)NSXMLParser *xmlParser;
 @property(strong,nonatomic)NSMutableData *responseData;
 @property(strong,nonatomic)NSMutableString *queryResult;
 @property(strong,nonatomic)NSString *trainId;
 @property(strong,nonatomic)NSString *destElement;

 @property(strong,nonatomic)IBOutlet UITextField *inputTrainInfo;
 -(IBAction)queryByTarinID:(id)sender;
 @end

连接输出口in putTrainInfo及操作queryByTrainId，如下：

4、修改ViewController.m，如下：

 #import "ViewController.h"

 @interface ViewController ()

 @end

 @implementation ViewController
 @synthesize conn;
 @synthesize soapMessage;
 @synthesize xmlParser;
 @synthesize responseData;
 @synthesize trainId;
 @synthesize destElement;
 @synthesize queryResult;
 @synthesize inputTrainInfo;
 - (void)viewDidLoad
 {
     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.
     //解析出的第几个值
     count = 0;
 }

 -(IBAction)queryByTarinID:(id)sender{
     count = 0;
     trainId = inputTrainInfo.text;
     destElement = @"getStationAndTimeByTrainCodeResult";
     soapMessage = [NSString stringWithFormat:@"<?xml version=\"1.0\" encoding=\"utf-8\"?>"
         "<soap12:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap12=\"http://www.w3.org/2003/05/soap-envelope\">"
         "<soap12:Body>"
         "<getStationAndTimeByTrainCode xmlns=\"http://WebXml.com.cn/\">"
         "<TrainCode>%@</TrainCode>"
         "<UserID>%@</UserID>"
         "</getStationAndTimeByTrainCode>"
         "</soap12:Body>"
         "</soap12:Envelope>",trainId,@""];
     NSLog(@"%@",soapMessage);
     // 创建URL
     NSURL *url = [NSURL URLWithString:@"http://webservice.webxml.com.cn/WebServices/TrainTimeWebService.asmx"];
     // 根据上面的URL创建一个请求
     NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
     NSString *msgLength = [NSString stringWithFormat:@"%d", [soapMessage length]];
     // 添加请求的详细信息，与请求报文前半部分的各字段对应
     [req addValue:@"application/soap+xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
     [req addValue:msgLength forHTTPHeaderField:@"Content-Length"];
     // 设置请求行方法为POST，与请求报文第一行对应
     [req setHTTPMethod:@"POST"];
     // 将SOAP消息加到请求中
     [req setHTTPBody: [soapMessage dataUsingEncoding:NSUTF8StringEncoding]];

     // 创建连接
     conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
     if (conn) {
         responseData = [NSMutableData data];
     }
 }

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

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

 -(void)showQueryResult{
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"查询结果"
                                                     message:[NSString stringWithFormat:@"%@", queryResult]
                                                    delegate:self
                                           cancelButtonTitle:@"确定"
                                           otherButtonTitles:nil];
     [alert show];
 }

 #pragma mark -
 #pragma mark URL Connection Data Delegate Methods

 // 刚开始接受响应时
 -(void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *) response{
     [responseData setLength: 0];
 }

 // 每接收到一部分数据就追加到responseData中
 -(void) connection:(NSURLConnection *)connection didReceiveData:(NSData *) data {
     [responseData appendData:data];
 }

 // 出现错误时
 -(void) connection:(NSURLConnection *)connection didFailWithError:(NSError *) error {
     conn = nil;
     responseData = nil;
 }

 // 完成接收数据时调用
 -(void) connectionDidFinishLoading:(NSURLConnection *) connection {
     NSString *responseXML = [[NSString alloc] initWithBytes:[responseData mutableBytes]
                                                 length:[responseData length]
                                               encoding:NSUTF8StringEncoding];
     printf("\n\n");

     // 打印出得到的XML
     NSLog(@"\n%@", responseXML);
     // 使用NSXMLParser解析出想要的结果
     xmlParser = [[NSXMLParser alloc] initWithData: responseData];
     [xmlParser setDelegate: self];
     [xmlParser setShouldResolveExternalEntities: YES];
     [xmlParser parse];
 }

 // 开始解析一个元素名
 -(void) parser:(NSXMLParser *) parser didStartElement:(NSString *) elementName namespaceURI:(NSString *) namespaceURI qualifiedName:(NSString *) qName attributes:(NSDictionary *) attributeDict {
     if ([elementName isEqualToString:destElement]) {
         if (!queryResult) {
             queryResult = [[NSMutableString alloc] init];
         }
         elementFound = YES;
     }

 }

 // 追加找到的元素值，一个元素值可能会追加多次
 -(void)parser:(NSXMLParser *) parser foundCharacters:(NSString *)string {
     if (elementFound) {
         switch (count++) {
             case 0:
                 //NSLog(@"车次%@",string);
                 [queryResult appendString: [NSString stringWithFormat:@"车次:%@\n",string]];
                 break;
             case 1:
                 //NSLog(@"发站%@",string);
                 if([string isEqualToString:@"数据没有被发现"]){
                     [queryResult deleteCharactersInRange:NSMakeRange(0, [queryResult length])];
                     [queryResult appendString: [NSString stringWithFormat:@"%@",string]];
                     //停止解析
                     [xmlParser abortParsing];
                     [self showQueryResult];
                     return;
                 }
                 [queryResult appendString: [NSString stringWithFormat:@"发站:%@\n",string]];
                 break;
             case 2:
                 //NSLog(@"到站%@",string);
                 [queryResult appendString: [NSString stringWithFormat:@"到站:%@\n",string]];
                 break;
             case 3:
                 break;
             case 4:
                 //NSLog(@"发车时间%@",string);
                 [queryResult appendString: [NSString stringWithFormat:@"发车时间:%@\n",string]];
                 break;
             case 5:
                 break;
             case 6:
                 //NSLog(@"到站时间%@",string);
                 [queryResult appendString: [NSString stringWithFormat:@"到站时间:%@\n",string]];
                 break;
             case 7:
                 //NSLog(@"里程%@",string);
                 [queryResult appendString: [NSString stringWithFormat:@"里程:%@公里\n",string]];
                 break;
             case 8:
                 //NSLog(@"运行时间%@",string);
                 [queryResult appendString: [NSString stringWithFormat:@"运行时间:%@小时\n",string]];
                 break;
             default:
                 break;
         }

     }
     //[queryResult appendString: string];
 }

 // 结束解析这个元素名
 -(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
     if ([elementName isEqualToString:destElement]) {
         [self showQueryResult];
         elementFound = FALSE;
         //停止解析
         [xmlParser abortParsing];
     }
 }

 // 解析整个文件结束
 - (void)parserDidEndDocument:(NSXMLParser *)parser {
     if (responseData) {
         responseData = nil;
     }
 }

 // 出错，例如强制停止解析
 - (void) parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError {
     if (queryResult) {
         queryResult = nil;
     }
 }
 @end

5、运行效果如下：

需要源码的网友请留言哦

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