Question

我是RestKit的初学者（我有一些iOS经验），我的NSArray没有填充RKMappingResult有些问题。它只在实际的“块”中填充自己，但如果我调用它来访问viewDidLoad（），它只会打印出null。

有人可以建议或提供任何文章的提示/链接吗？

非常感谢！

这是我的代码 -

-(void) loadData
{

    RKObjectMapping *mapping = [RKObjectMapping mappingForClass:[Venue class]];
    [mapping addAttributeMappingsFromDictionary:@{
     @"name":   @"name", @"location.address" : @"address", @"location.city" : @"city"}];

    NSString *urlString = [NSString stringWithFormat:@"https://api.foursquare.com/v2/venues/search?ll=55.903324,-3.171383&categoryId=4bf58dd8d48988d18f941735&client_id=%s&client_secret=%s&v=20130717", kCLIENTID, kCLIENTSECRET];
    NSURL *baseUrl = [NSURL URLWithString:urlString];

    RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:mapping method:RKRequestMethodAny pathPattern:nil keyPath:@"response.venues" statusCodes:nil];

    NSURLRequest *request = [NSURLRequest requestWithURL:baseUrl];

    RKObjectRequestOperation *operation = [[RKObjectRequestOperation alloc] initWithRequest:request responseDescriptors:@[responseDescriptor]];

    [operation setCompletionBlockWithSuccess:^(RKObjectRequestOperation *operation, RKMappingResult *result) {
        //set the array of venues to be the result of what we got back
        //NSLog(@"%@", [result array]);

        NSArray *venues = [result array];
        self.arrayOfVenues = venues; //self.arrayOfVenues is always null when I call it in the other methods
    } failure:nil];
    [operation start];
}


- (void) viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:YES];
    NSLog(@"%@", self.arrayOfVenues);

}

- (void)viewDidLoad
{
    [super viewDidLoad];
    //load the venue data
    self.title = @"Venues";
    [self loadData];
    NSLog(@"%@", self.arrayOfVenues);
}

Answer 1

你必须分配＆amp; init数组。像这样

 NSArray *venues =[[NSArray alloc]init];
 venus=[result array];

Answer 2

尝试self.arrayOfVenues = [venues copy];

我认为当你离开街区时，你可能会失去对“场地”的引用，而且这个变量就会消失。

另外：

它只会填充实际的“阻止”，但如果我打电话访问它在viewDidLoad（）中，只打印出null。

请记住，在尝试访问阵列之前，需要完成此块。 viewDidLoad肯定会在此块完成之前触发，viewDidAppear也是如此。

Restkit - NSArray属性始终为null

2 个答案: