如何抓取XML元素并存储它？目标C
如何抓取XML元素并存储它？目标C
提问于 2013-07-26 09:09:49
我正试着从一个网站上得到一个标记。成功身份验证后，将显示一个XML文档。
我创建了一个连接，如下所示：
NSString *strURLQueryString = [NSString stringWithFormat:@"%@?username=%@&password=%@", kURL_LOGIN, nameString, passwordString];
NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:strURLQueryString]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];为了显示输出，我使用了以下内容：
unsigned char byteBuffer[[receivedData length]];
[receivedData getBytes:byteBuffer];
NSLog(@"Output: %s", (char *)byteBuffer);因此，返回的文档的一些输出如下所示：
<status>0</status><reason>User fetched.</reason><token>9cb7396dccabe68c067521db219afb83</token>我读过许多XML解析实现，但是我无法实现它，因为它不能满足我的需要，我只是无法理解其解释的复杂性。
如果有人能给我一个好的建议，我会很感激的。
回答 3
Stack Overflow用户
回答已采纳
发布于 2013-07-26 13:05:46
- (XMLParserViewController *) initXMLParser {
appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
return self;
}
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName
attributes:(NSDictionary *)attributeDict
{
if([elementName isEqualToString:@"Books"]) {
appDelegate.books = [[NSMutableArray alloc] init];
}
else if([elementName isEqualToString:@"Book"])
{
aBook = [[Books alloc] init];
}
NSLog(@"Processing Element: %@", elementName);
}
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
if(!currentElementValue)
currentElementValue = [[NSMutableString alloc] initWithString:string];
else
[currentElementValue appendString:string];
NSLog(@"Processing Value: %@", currentElementValue);
}
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
if([elementName isEqualToString:@"Books"])
return;
if([elementName isEqualToString:@"Book"])
{
[appDelegate.books addObject:aBook];
aBook = nil;
}
else if([elementName isEqualToString:@"name"])
{
aBook.name=currentElementValue;
}
else if([elementName isEqualToString:@"address"])
{
aBook.address=currentElementValue;
}
else if([elementName isEqualToString:@"country"])
{
aBook.country=currentElementValue;
}
currentElementValue = nil;
NSLog(@"%@",aBook.name);
NSLog(@"%@",aBook.address);
NSLog(@"%@",aBook.country);
}试试这个，我希望这个有用..。
Stack Overflow用户
发布于 2013-07-26 09:28:09
相关的NSXMLParserDelegate方法：
-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName //etc
{ _inToken = [elementName isEqualToString:@"token"]; }
-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName //etc
{ _inToken = NO; }
-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
if (_inToken) {
_token = string;
[parser abortParsing];
}
}Stack Overflow用户
发布于 2013-07-26 15:06:39
您应该使用XML解析器。这是很容易使用的，采取以下所有步骤以获得最佳效果：
从XMLParser创建NSXMLParser类子类，因此您有一个NSXMLParser.h和NSXMLParser.m类
您的.h类必须如下所示：
#import <Foundation/Foundation.h>
@interface XMLParser : NSXMLParser <NSXMLParserDelegate>{
NSUInteger parsedCounter;
BOOL accumulatingParsedCharacterData;
BOOL didAbortParsing;
}
@property (nonatomic, strong) NSMutableString *currentParsedCharacterData;
@property (nonatomic, strong) NSMutableArray *currentParsedCharacterArray;
@end和.m类：
#import "XMLParser.h"
@implementation XMLParser
#pragma mark Parser constants
// Limit the number of parsed data to 100.
static const NSUInteger kMaximumNumberOfFilesToParse = 100;
static NSUInteger const kSizeOfFileBatch = 10;
// Reduce potential parsing errors by using string constants declared in a single place.
static NSString * const kEntryElementName = @"dlResult";
static NSString * const kStringElementName = @"string";
#pragma mark NSXMLParser delegate methods
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict {
// NSLog(@"didStart");
// If the number of parsed earthquakes is greater than kMaximumNumberOfEarthquakesToParse, abort the parse.
if (parsedCounter >= kMaximumNumberOfFilesToParse) {
// Use the flag didAbortParsing to distinguish between this deliberate stop and other parser errors.
didAbortParsing = YES;
[self abortParsing];
}
if ([elementName isEqualToString:kEntryElementName]) {
_currentParsedCharacterArray = [[NSMutableArray alloc]init];
} else if ([elementName isEqualToString:kStringElementName]) {
accumulatingParsedCharacterData = YES;
_currentParsedCharacterData = [[NSMutableString alloc]init];
}
}
// return string between tags
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
// NSLog(@"foundCh");
if (accumulatingParsedCharacterData) {
// If the current element is one whose content we care about, append 'string'
// to the property that holds the content of the current element.
[_currentParsedCharacterData appendString:string];
NSLog(@"currentParsedCharacterData:%@",_currentParsedCharacterData);
}
}
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
// NSLog(@"didEnd");
if ([elementName isEqualToString:kStringElementName]) {
[_currentParsedCharacterArray addObject:_currentParsedCharacterData];
}
accumulatingParsedCharacterData = NO;
}
- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError {
if (didAbortParsing == NO) {
// Pass the error to the main thread for handling.
[self performSelectorOnMainThread:@selector(handleError:) withObject:parseError waitUntilDone:NO];
}
}
@end在.m类中有两个const字符串：
static NSString * const kEntryElementName = @"dlResult";
static NSString * const kStringElementName = @"string";这些是字符串标记，您应该实现的标记是“状态”、“原因”“令牌”。
从connection类中，将数据连接发送到XMLParser类，如下所示：
@autoreleasepool {
// 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.
//
XMLParser *parser = [[XMLParser alloc] initWithData:data];
parser.currentParsedCharacterArray = [NSMutableArray array];
parser.currentParsedCharacterData = [NSMutableString string];
[parser setDelegate:parser];
[parser parse];
// depending on the total number of earthquakes parsed, the last batch might not have been a "full" batch, and thus
// not been part of the regular batch transfer. So, we check the count of the array and, if necessary, send it to the main thread.
if ([parser.currentParsedCharacterArray count] > 0) {
// send parsed data to another class or ...
// parser.currentParsedCharacterArray is parsed data
}
parser.currentParsedCharacterArray = nil;
parser.currentParsedCharacterData = nil;
}如果你有什么问题，问我！
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/17877304
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