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目标C问题：

我有一个 ViewController 的超类和一个数据控制器的超类。数据控制器有委托通知 ViewController 何时更新。这一切似乎都有效，但是在输入一些日志之后，委托方法似乎每次都被调用两次。我想我实际上可能有每个 SubDataController 的两个实例。我一定在某处实例化了一些错误。谁能看到我做错了什么？

我有一个数据密集型应用程序的单独屏幕。我设置了它，以便有一个 UIViewController 的超类，它们都继承自：

DmsProgressBaseViewController.h

@class DmsProgressDataController;

@interface DmsProgressBaseViewController : UIViewController

@property(readonly,assign,nonatomic)DmsProgressDataController *dataController;
//index, so we be identified in container
@property(assign,nonatomic)NSInteger index;

@end

DmsProgressBaseViewController.m

@implementation DmsProgressBaseViewController

@synthesize dataController=_dataController;


- (void)viewDidLoad
{
    [super viewDidLoad];
}

-(DmsProgressDataController*)dataController
{
    if(!_dataController){
        _dataController=[[DmsProgressDataController alloc]init];
    }
    return _dataController;
}

.....

@end

如您所见，每个视图都有一个数据控制器，它通过休息服务加载数据并将其导入核心数据。它也继承自：DmsProgressDataController.h

@class AFHTTPRequestOperation;
@class DmsProgressDataController;

@protocol DmsProgressDataControllerDelegate

-(void)dataLoadedSuccessfully;

@end


@interface DmsProgressDataController : NSObject

@property(nonatomic,assign)id delegate;
@property(nonatomic, strong)NSString *resourceUrl;
-(void)loadDataFromRest;
-(void)loadDataFromRest:(NSString*)resourceUrl;
-(void)handleRestSuccess:(id)jsonResponse;
-(void)handleRestError:(NSError*)error forOperation:(AFHTTPRequestOperation*)operation;

//delegate method
-(void)notifyDataLoadedSuccessfully;

@end

DmsProgressDataController.m @implementation DmsProgressDataController

- (id)init
{
    self = [super init];
    if (self) {

    }
    return self;
}

-(void)loadDataFromRest
{
    NSLog(@"loading %@",self.resourceUrl);
    if(self.resourceUrl!=nil){
        [self loadDataFromRest:self.resourceUrl];
    }
}
....

#pragma mark - delegate methods
-(void)notifyDataLoadedSuccessfully
{
    if(self.delegate!=nil){
        [self.delegate dataLoadedSuccessfully];
    }
}
@end

所以那些是超级类......

子类的一个例子是：DmsProgressOverallViewController.h @class DmsProgressOverallDataController;

@interface DmsProgressOverallViewController : DmsProgressBaseViewController

@property(readonly,strong,nonatomic)DmsProgressOverallDataController *dataController;

@end

DmsProgressOverallViewController.m

@interface DmsProgressOverallViewController ()<DmsProgressDataControllerDelegate>

@end

@implementation DmsProgressOverallViewController
@synthesize dataController=_dataController;
- (void)viewDidLoad
{
    [super viewDidLoad];
[self.dataController loadDataFromRest:@"overall"];
    self.dataController.delegate=self;
}

-(DmsProgressDataController*)dataController
{
    if(!_dataController){
        _dataController=[[DmsProgressOverallDataController alloc]init];
    }
    return _dataController;
}
#pragma mark - datacontroller delegate method
-(void)dataLoadedSuccessfully
{
    NSLog(@"Overall data loaded successfully");
}

@end

使用数据控制器：

DmsProgressOverallDataController.h

@interface DmsProgressOverallDataController : DmsProgressDataController

@end

DmsProgressOverallDataController.m

@implementation DmsProgressOverallDataController


-(id)init
{
    if(self=[super init]){
        self.resourceUrl=@"progress/totals";
    }

    return self;
}

-(void)handleRestSuccess:(id)jsonResponse
{
    NSString *defaultClg=[jsonResponse objectForKey:@"defaultClg"];
    NSArray *clgs=[jsonResponse objectForKey:@"colleges"];
    for(NSString *clg in clgs){
        College *college =[College MR_createEntity];
        college.collegeName=clg;
        if([defaultClg isEqualToString:clg]){
            college.defaultClg=[NSNumber numberWithBool:YES];
        }
    }

    //DataController delegate method called here
    if(self.delegate!=nil){
        [self.delegate dataLoadedSuccessfully];
    }

}

@end

我希望这提供了足够的信息。再次感谢您的所有帮助！

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1 回答 1

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您在 SubViewController 中有一个实例变量名称和属性名称，它们也存在于超类 SuperViewController 中。您在超类和类中合成属性名称。我怀疑发生的事情是 SubViewClass 中的 _dataController 是从 SuperViewController 继承的 _dataController。您没有提供足够的代码来查看 dataController 是如何使用的，但是如果您有不同的 ivar 和属性名称 (a) 阅读起来会更容易混淆，并且 (b) 它可能会解决双重调用问题。试试看！

于 2013-08-02T04:47:07.277 回答