Question

我正在尝试在我的应用中实现以下代码，但会抛出异常。我需要从日期中提取年，月，日并将它们传递给谓词。例外是在行：

NSPredicate *yearPredicate = [NSPredicate predicateWithFormat:@"todoYear == %@", yearBuscado];

这是完整的方法代码：

 - (NSFetchedResultsController *)fetchedResultsController
    {
      if (fetchedResultsController) return fetchedResultsController;

      NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
      NSEntityDescription *entity = 
                   [NSEntityDescription entityForName:@"FavoriteThing" 
                               inManagedObjectContext:managedObjectContext];

      [fetchRequest setEntity:entity];

      NSSortDescriptor *sortDescriptor = 
                  [[NSSortDescriptor alloc] initWithKey:@"displayOrder" 
                                              ascending:YES];

      NSArray *sortDescriptors = [[NSArray alloc] 
                                  initWithObjects:sortDescriptor, nil];
        //SOLO TO-DOS DE TODAY


        todayDate = [NSDate date];

        NSCalendar* calendar = [NSCalendar currentCalendar];
        NSDateComponents* components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSHourCalendarUnit|NSMinuteCalendarUnit fromDate:todayDate]; // Get necessary date components

        NSString *yearStr = [NSString stringWithFormat:@"%ld", (long)[components year]];
        NSString *monthStr = [NSString stringWithFormat:@"%ld", (long)[components month]];
        NSString *dayStr = [NSString stringWithFormat:@"%ld", (long)[components day]];
        NSString *hourStr = [NSString stringWithFormat:@"%ld", (long) [components hour]];
        NSString *minuteStr = [NSString stringWithFormat:@"%ld", (long) [components minute]];


        NSNumber *yearBuscado = (long)[components year];
        NSNumber *mesBuscado = (long) [components month];
        NSNumber *diaBuscado = (long) [components year];
        NSString *tipourgente = @"Urgent";
        NSString *tipocolor = @"Yellow";
        NSPredicate *yearPredicate = [NSPredicate predicateWithFormat:@"todoYear == %@", yearBuscado];
        NSPredicate *monthPredicate = [NSPredicate predicateWithFormat:@"todoMonth == %@", mesBuscado];
        NSPredicate *dayPredicate = [NSPredicate predicateWithFormat:@"todoDay == %@", diaBuscado];
        NSPredicate *urgentPredicate = [NSPredicate predicateWithFormat:@"urgent == %@", tipourgente];
        NSPredicate *colorPredicate = [NSPredicate predicateWithFormat:@"color == %@", tipocolor];

      [fetchRequest setSortDescriptors:sortDescriptors];






      NSPredicate *busqueda = [NSCompoundPredicate andPredicateWithSubpredicates:@[yearPredicate, monthPredicate,dayPredicate,urgentPredicate]];

        [fetchRequest setPredicate:busqueda];
      NSFetchedResultsController *aFetchedResultsController =
                  [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest 
                                                      managedObjectContext:managedObjectContext
                                                        sectionNameKeyPath:nil cacheName:nil];
      aFetchedResultsController.delegate = self;
      [self setFetchedResultsController:aFetchedResultsController];


      [aFetchedResultsController release];
      [fetchRequest release];
      [sortDescriptor release];
      [sortDescriptors release];


      return fetchedResultsController;
    }

Answer 1

问题在于：

NSNumber *yearBuscado = (long)[components year];

as [components year]返回一个整数，而不是NSNumber个对象。它应该是

NSNumber *yearBuscado = [NSNumber numberWithLong:[components year]];

或更好，使用“盒装表达式”的新语法：

NSNumber *yearBuscado = @([components year]);

或者，使用

NSInteger yearBuscado = [components year];

并将您的谓词更改为

NSPredicate *yearPredicate = [NSPredicate predicateWithFormat:@"todoYear == %ld", (long)yearBuscado];

使用NSPredicate进行变量格式化的异常

1 个答案: