Question

我从Web查询中返回了一些XML，并在标记内包含多个参数，如下所示：

<game>
    <name>First game title</name>
    <id>12345</id>
    <desc>A game..</desc>
</game>
<game>
    <name>Second game title</name>
    <id>67890</id>
    <desc>Another game..</desc>
</game>

我正在使用NSXMLParser来解析它，并且当我对它们进行NSLog时，它会逐行将每一行吐出到我的控制台中。我正在尝试将每个<game>提供给我的Game个对象中，其名称为NSString，ID为NSNumber等。但是，我正在努力弄清楚我是如何判断的它开始一个新对象，因为在我的任何NSLog语句中都没有返回<game>标记，只有那些有实际数据的标记（例如每个名称，id等）

如果我想将每个<game> </game>标记内的所有数据都放到一个单独的对象中，我该怎么办？这是解析器代码：

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict {
    element = [NSMutableString string];
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {

    NSLog(@"ELEMENT TYPE: %@ VALUE: %@", elementName, element);

}

Answer 1

首先让自己成为一个游戏类。我们将XML解析为Games对象。

Game.h就是这样：

@interface Game : NSObject

@property (nonatomic, retain) NSString *name;
@property (nonatomic, retain) NSNumber *gameID;
@property (nonatomic, retain) NSString *gameDescription;

@end

现在在类中解析XML（在本例中为ViewController），创建一个NSMutableArray属性来存储我们解析它们时的Game对象，一个Game属性用于创建新的Game对象，一个NSString属性将我们正在解析的当前元素存储在XML中，以及我们正在使用的NSXMLParser实例的属性。还要确保它符合NSXMLParserDelegate协议。

所以标题ViewController.h：

@interface ViewController : UIViewController <NSXMLParserDelegate>

@property (nonatomic, retain) NSString *currentElement;
@property (nonatomic, retain) NSMutableArray *games;
@property (nonatomic, retain) Game *gameBeingParsed;
@property (nonatomic, retain) NSXMLParser *xmlParser;

@end

现在在ViewController.m实现中我们解析XML：

#import "ViewController.h"

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Make an NSMutableArray to put the parsed Game objects in
    self.games = [NSMutableArray array];

    // Get the XML data to parse
    // We need it in an NSdata object
    NSString *xmlString = @"<?xml version=\"1.0\" encoding=\"utf-8\"?><xml><game><name>First game title</name><id>12345</id><desc>A game..</desc></game><game><name>Second game title</name><id>67890</id><desc>Another game..</desc></game></xml>";
    NSData *xmlData = [xmlString dataUsingEncoding:NSStringEncodingConversionAllowLossy];

    // Set up an NSXMLParser to use
    // Set the delegate and start parsing!
    self.xmlParser = [[[NSXMLParser alloc] initWithData:xmlData] autorelease];
    _xmlParser.delegate = self;
    [_xmlParser parse];


}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict {

    // If we have a <game> tag then we are starting to parse a new Game object
    if ([elementName isEqualToString:@"game"]) {
        self.gameBeingParsed = [[[Game alloc] init] autorelease];
    }

    // If not then we need to keep track of the element name so we know which property to set on the Game object
    else {
        self.currentElement = elementName;
    }

}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {

    // If we have a closing </game> tag we are done parsing a Game so add it to the array
    if ([elementName isEqualToString:@"game"]) {
        [_games addObject:_gameBeingParsed];
    }
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    // Work out which element we have the characters for
    // Then set the property of the Game object
    if ([_currentElement isEqualToString:@"name"]){
        _gameBeingParsed.name = string;
    }
    if ([_currentElement isEqualToString:@"id"]){
        _gameBeingParsed.gameID = [NSNumber numberWithInt:[string intValue]];
    }
    if ([_currentElement isEqualToString:@"name"]){
        _gameBeingParsed.gameDescription = string;
    }
}

- (void)parserDidEndDocument:(NSXMLParser *)parser{

    // We are done parsing XML
    NSLog(@"Parsed %d Games", _games.count);
    for (Game *game in _games) {
        NSLog(@"%@ : %@ : %@", game.name, game.gameID, game.gameDescription);
    }
}

解析完成后，我们在parserDidEndDocument中得到一个回调：此时，我们将在游戏实例中填充_games属性。

将XML提供给自定义对象？

1 个答案: