通過委託方法攜帶自定義屬性

Question

我目前正在拉取與其綁定位置信息的「比賽」對象列表。我想監視我在附近的所有比賽。

 for(Contest *contest in contests) { 

      NSMutableDictionary * fence1 = [NSMutableDictionary new]; 
      [fence1 setValue:contest.event.name forKey:@"identifier"]; 
      [fence1 setValue:[NSString stringWithFormat:@"%f", contest.location.latitude] forKey:@"latitude"]; 
      [fence1 setValue:[NSString stringWithFormat:@"%f", contest.location.longitude] forKey:@"longitude"]; 
      [fence1 setValue:@"1000" forKey:@"radius"]; 

      //the below method returns a CLRegion object 
      CLRegion *region = [self dictToRegion:fence1]; 

      //adding custom contest object to region 
      region.contest = contest; 

      [self.locationManager requestStateForRegion:region]; 
     } 

我也想自定義比賽財產綁在區域（如上面的代碼所示），但它似乎並沒有在委託方法didDetermineState結轉：

-(void)locationManager:(CLLocationManager *)manager didDetermineState:(CLRegionState)state forRegion:(CLRegion *)region { 
switch (state) { 
    case CLRegionStateUnknown: 
     NSLog(@"Unknown state!"); 
     break; 

    case CLRegionStateInside: 
     NSLog(@"Inside state!"); 

     //this comes back as null 
     NSLog(@"%@", region.contest.name); 

     break; 

    case CLRegionStateOutside: 
     NSLog(@"Outside state!"); 
     break; 

    default: 
     break; 
} 
} 

在委託方法中，region.contest返回爲（null）。有更好的方法嗎？

附錄（我的類別CLRegion）： CLRegion + Contest.h：

#import <CoreLocation/CoreLocation.h> 
#import "Event.h" 
#import "Contest.h" 

@interface CLRegion (Loopd) 

@property (nonatomic, strong) Event *event; 
@property (nonatomic, strong) Contest *contest; 

@end 

CLRegion + Contest.m：

#import "CLRegion+Loopd.h" 
#import <objc/runtime.h> 

static char defaultHashKey; 

@implementation CLRegion (Loopd) 

@dynamic event; 
@dynamic contest; 

-(Event*) event { 
    return objc_getAssociatedObject(self, &defaultHashKey); 
} 

- (void) setEvent:(Event *)event { 
    objc_setAssociatedObject(self, &defaultHashKey, event, OBJC_ASSOCIATION_RETAIN_NONATOMIC); 
} 

-(Contest*) contest { 
    return objc_getAssociatedObject(self, &defaultHashKey); 
} 

- (void) setContest:(Contest *)event { 
    objc_setAssociatedObject(self, &defaultHashKey, event, OBJC_ASSOCIATION_RETAIN_NONATOMIC); 
} 


@end 

Answer 1

有2個問題，你的類別。 1.您對兩個屬性都使用相同的密鑰。 2. defaultHashKey用0值初始化。

objc_getAssociatedObject和objc_setAssociatedObject的工作方式大多像setValue：forKey：和getValueForKey :.所以你需要提供將值綁定到對象的鍵。嘗試類似的東西：

#import "CLRegion+Loopd.h" 
#import <objc/runtime.h> 

static char* kEventKey = "kEventKey"; 
static char* kContestKey = "kContestKey"; 

@implementation CLRegion (Loopd) 

@dynamic event; 
@dynamic contest; 

-(Event*) event { 
    return objc_getAssociatedObject(self, kEventKey); 
} 

- (void) setEvent:(Event *)event { 
    objc_setAssociatedObject(kEventKey, event, OBJC_ASSOCIATION_RETAIN_NONATOMIC); 
} 

-(Contest*) contest { 
    return objc_getAssociatedObject(self, kContestKey); 
} 

- (void) setContest:(Contest *)event { 
    objc_setAssociatedObject(self, kContestKey, event, OBJC_ASSOCIATION_RETAIN_NONATOMIC); 
} 

@end 

此代碼應工作，但會好得多用於存儲這種關聯（我不使用運行時爲這種目的的一大風扇）創建單獨的對象。

編輯： 您在for循環中多次分配比賽值。因此，其中一個比賽（最後一個）被分配給CLRegion對象。