Question

我正在处理1个应用程序，该应用程序需要多次调用Web服务器以检索所有数据，因为每个请求的限制为25个项目。如何使用XMLParser做到这一点？

在“ startParsing”方法中，我们使用URL初始化NSXMParser并设置委托。由于服务器限制，我们如何多次调用XML解析器或多次从服务器请求数据？我们需要更改URL还是什么？

-(void)startParsing{  

    NSXMLParser *xmlparser = [[NSXMLParser alloc] initWithContentsOfURL:[NSURL URLWithString:@"http://musicbrainz.org/ws/2/place/?query=placeAND%20type:StudioANDbegin:[1990%20TO%202018]"]];

    [xmlparser setDelegate:self];
    [xmlparser parse];

    if (_brainzXMLData.count != 0) {

    }
}

#pragma mark - NSXML Delegate methods
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString     *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict;
{
    //Retrieving metadata and place objects
    if ([elementName isEqualToString:@"metadata"]) {
        _brainzXMLData = [[NSMutableArray alloc] init];
    }
    if ([elementName isEqualToString:@"place"]) {
        _brainzDictXMLPart = [[NSMutableDictionary alloc] init];
    }

}
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string;
{
    if (!_brainzXMLString) {
        _brainzXMLString = [[NSMutableString alloc] initWithString:string];
    }
    else {
        [_brainzXMLString appendString:string];
    }
}
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName;
{
    //Here we retrieve useful information and save it in 'brainzXMLData' dictionary. 
    if ([elementName isEqualToString:@"name"]) { //If elementName is name, set object and dictionary here.
        [_brainzDictXMLPart setObject:_brainzXMLString forKey:elementName];
    }
    if ([elementName isEqualToString:@"begin"]) { //If elementName is begin, set object and dictionary here.
        [_brainzDictXMLPart setObject:_brainzXMLString forKey:elementName];
    }
    if ([elementName isEqualToString:@"end"]) {   //If elementName is end, set object and dictionary here.
        [_brainzDictXMLPart setObject:_brainzXMLString forKey:elementName];
    }
    if ([elementName isEqualToString:@"place"]) { // Add all data into brainzXMLData dictionary.
        [_brainzXMLData addObject:_brainzDictXMLPart];

    }
    _brainzXMLString = nil;
}

多次调用XMLParser

0 个答案: