Question

我正在研究一个nsxml解析器，我有一些问题。我正在使用nsxml解析器来解析日期。我想获得仅2天的信息。不是全部4个来自google weather api。我该怎么办？

NSMutableArray *array=[NSMutableArray arrayWithObjects:startDate,endDate,Nil];
for (NSDate *date in array)
{
     if([date isEqualToDate:dd])
     {
         NSManagedObject *allnew = Nil;
         NSManagedObjectContext *allone=[self managedObjectContext];            
         NSEntityDescription *entity = [NSEntityDescription entityForName:@"Weather" inManagedObjectContext:allone];   
         NSLog(@" The NEW ENTITY IS ALLOCATED AS entity is %@",entity);
         WeatherXMLParser *delegate = [[WeatherXMLParser alloc] initWithCity:city state:state country:country];
         NSXMLParser *locationParser = [[NSXMLParser alloc] initWithContentsOfURL:delegate.url];
         [locationParser setDelegate:delegate];
         [locationParser setShouldResolveExternalEntities:YES];
         [locationParser parse];
         NSFetchRequest *request = [[NSFetchRequest alloc] init];  
         [request setEntity:entity]; 

         predicate = [NSPredicate predicateWithFormat:
                                    @"city == %@ and state == %@ and country == %@  and date==%@ and date==%@", city, state, country,startDate,endDate];
         [request setPredicate:predicate];
         NSError *err;
         NSUInteger count = [allone countForFetchRequest:request error:&err];
         NSLog(@" minimum salary is %@",predicate);
         // If a predicate was passed, pass it to the query
         if(predicate !=NULL){
              [self deleteobject];
         }

         Weather *weather = (Weather *)[NSEntityDescription insertNewObjectForEntityForName:@"Weather" 
                                                                                   inManagedObjectContext:self.managedObjectContext];
         weather.date = [fields objectForKey:@"date"];
         weather.high =[fields objectForKey:@"high"];
         weather.low = [fields objectForKey:@"low"];
         weather.city =[fields objectForKey:@"city"];
         weather.state =[fields objectForKey:@"state"];
         weather.country =[fields objectForKey:@"country"];
         NSString*icon=[fields objectForKey:@"icon"];
         NSString *all=[icon lastPathComponent];
         weather.condition = all;

         [self saveContext]; 
     }

Answer 1

我不熟悉你的XML文件是如何组织的但我认为问题是有4个以上的节点具有相同的名称，你只想要2.当我遇到类似的情况时，我设置了一个标志对于我自己想要的最后一个节点之后，我从来没有读过任何其他节点。

在您的特定情况下，创建一个计数器，显示您已阅读的天数，解析时检查以确保节点名称为“date”（或者您现在正在执行的任何操作以触发读取信息）并且您的计数器小于2.请确保每次调用天气更新时都重置计数器。

编辑一些示例代码：

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

    if ([elementName isEqualToString:@"Day"] && daysRead < 2) {    
        if ([[attributeDict objectForKey:@"high"] integerValue] > 0) {
            //Store store this value
        }
        if ([[attributeDict objectForKey:@"low"] integerValue] > 0) {
            //Store this value
        }
    }
}

这是我的解析器的一部分，我有点为你重写它。您感兴趣的部分是变量'daysRead'。我建议使用这样的东西来跟踪你已经阅读和存储的天数。如果您有两个以上，则根本不解析剩余的天数。在完成每个已解析的元素之后，不要忘记增加它。

希望这有帮助！

-Karoly

如何匹配解析器中的nsxml日期并仅获取所需的日期

1 个答案: