如何解決這個「指標0超越界限空陣！」

Question

我有檢查時，一個問題，如果有一個從數據庫來的東西：

代碼：

hourPrograma: @"12:00"; 
NSArray *hourLinha = [hourProgram componentsSeparatedByString:@":"]; 

NSArray * test = [notificationDAO selectHourMin:[hourLinha[0] intValue]:[hourLinha[1] intValue]]; 

if (!test[0]) { 
    NSLog(@"ok!!!"); 
} else { 
    NSLog(@"empty!!!"); 
} 

我的查詢：

-(NSArray *) selectHourMin:(NSInteger *) hour: (NSInteger *) min { 
    query = [NSString stringWithFormat:@"SELECT hour, min FROM notification WHERE %i = hour AND %i = min", hour, min]; 
    NSArray * resp = [self loadDataFromDB:query]; 
    return resp; 
} 

當我檢查它是否爲空或者是否返回了某個內容時，會顯示錯誤。

Answer 1

test[0]已經在試圖下標數組代替測試。你需要檢查的count屬性：

if (test.count) { 
    // ... 
} 

Answer 2

[0]與

test.count > 0 

Answer 3

你需要檢查結果爲：

if (test.count > 0) 
{  
    NSLog(@"ok!!!"); 
} 
else 
{  
    NSLog(@"empty!!!"); 
} 

希望這會有所幫助。

Answer 4

用正楷在功能:)

-(void) selectHourMin:(NSInteger *) hour: (NSInteger *) min success:(void (^)(NSArray *result))successBlock failure:(void (^)(NSString * error))failureBlock{ 
    query = [NSString stringWithFormat:@"SELECT hour, min FROM notification WHERE %i = hour AND %i = min", hour, min]; 
    NSArray * resp = [self loadDataFromDB:query]; 

    if (resp.count > 0) { 
     successBlock(resp); 
    }else{ 
    failureBlock(@"empty result"); 
    } 
} 

，並呼籲

hourPrograma: @"12:00"; 
NSArray *hourLinha = [hourProgram componentsSeparatedByString:@":"]; 

NSArray * test = [notificationDAO selectHourMin:[hourLinha[0] intValue]:[hourLinha[1] intValue]]; 

[self selectHourMin:1 :2 success:^(NSArray *result) { 
    NSLog(@"result: %@", result); 
} failure:^(NSString *error) { 
    NSLog(@"%@", error); 
}];