Cocoa 解析xml文件

苹果提供了解析xml的类，NSXMLParser及其代理NSXMLParserDelegate

 

展示一段事例代码，自己的小应用中用到的：

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"question" ofType:@"xml"];NSData *xmlData = [[NSData alloc] initWithContentsOfFile:filePath];if (xmlData == nil) {NSLog(@"File read failed!");}NSXMLParser *parser = [[NSXMLParser alloc] initWithData:xmlData];[parser setDelegate:self];[parser parse];[parser release];[xmlData release]; 

其中当前的viewController实现了NSXMLParserDelegate协议，具体实现一下几个方法：

- (void)finishedCurrentQuestion {[self.itemArray addObject:self.currentQuestion];self.currentQuestion = nil;}#pragma mark NSXMLParserDelegatestatic NSString *kName_Question= @"question";static NSString *kName_Title= @"title";static NSString *kName_Reverse= @"reverse";- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict {if ([elementName isEqualToString:kName_Question]) {QuestionItem *item = [[QuestionItem alloc] init];self.currentQuestion = item;[item release];} else if ([elementName isEqualToString:kName_Title] || [elementName isEqualToString:kName_Reverse]){[currentString setString:@""]; storingChar = YES;}}- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {if ([elementName isEqualToString:kName_Question]) { [self finishedCurrentQuestion]; } else if ([elementName isEqualToString:kName_Title]) { self.currentQuestion.title = currentString; } else if ([elementName isEqualToString:kName_Reverse]) { self.currentQuestion.reverse = [currentString boolValue];; } storingChar = NO;}- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string { //if (storingCharacters) [currentString appendString:string];if (storingChar) {[self.currentString appendString:string];}}- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError { // Handle errors as appropriate for your application.} 

 

由此可见，NSXMLParser其实并不涉及真正的解析业务，所有的操作都在NSXMLParserDelegate中，复用性极强，代理模式的优点体现的淋漓尽致。