排序描述符无法正常或一致地运行 [英] Sort Descriptor Not functioning correctly or consistently

问题描述

我在 4 个实体之间使用排序描述符和集合谓词.

I am using a sort descriptor and a set predicate between 4 entities.

实体一:锻炼类型关系锻炼 1 对多实体二:锻炼集关系日 1 到多实体三:锻炼日关系练习 1 对多实体四:锻炼运动

entity one: workoutType Relationship workouts 1 to many entity two: workoutSet Relationship days 1 to many entity three: workoutDay relationship exercises 1 to many entity four: workoutExercise

也设置了逆.

我收到的问题是 sortDescriptor 在后台正常工作，但显示的内容不正确.

The problem i am receiving is that the sortDescriptor is working correctly behind the scenes, but what is displayed is incorrect.

例如，在我的 trainingDay 实体中，我有字符串类型的属性 dayName.

For example in my workoutDay entity i have attribute dayName of string type.

存储值:第 1 天、第 2 天、第 3 天.

stored values: day 1, day 2, day 3.

在 tableview 中运行时显示值:第 1 天、第 3 天、第 2 天.

when run shown values in tableview: day 1, day 3, day 2.

当我从上到下点击日期时:

When i click on the days from top to bottom:

第 1 天....下一个视图控制器显示正确的第 1 天数据.

day 1....next view controller shows correct day 1 data.

第 3 天....下一个视图控制器显示第 2 天的数据(不是第 3 天).

day 3....next view controller shows day 2 data (Not day 3).

第 2 天....下一个视图控制器显示第 3 天的数据(不是第 2 天).

day 2....next view controller shows day 3 data (Not day 2).

所以排序描述符正在工作，但显示的内容与选择的内容无关.

So the sort descriptor is working but what is shown does not correlate to what is being selected.

代码:

-(void)fetchWorkoutDays
{
    NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"WorkoutDay"];
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"workoutSet = %@", self.workoutSet];
    [fetchRequest setPredicate:predicate];
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"dayName" ascending:YES];
    [fetchRequest setSortDescriptors:@[sortDescriptor]];
    self.fetchedResultsController = [[NSFetchedResultsController alloc]
                                 initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext
                                 sectionNameKeyPath:nil cacheName:nil];
    //self.fetchedResultsController.delegate = self;
    NSError *error;
    if (![self.fetchedResultsController performFetch:&error])
    {
        NSLog(@"Fetch failed: %@", error);
    }

 }


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
     static NSString *CellIdentifier = @"Cell";
     UITableViewCell *cell =
     [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
     if (cell == nil)
     {
         cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
                                  reuseIdentifier:CellIdentifier];
         cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
     }
     WorkoutDay *day = [self.workoutSet.days.allObjects objectAtIndex:indexPath.row];

     cell.textLabel.text = day.dayName;
     return cell;
}

感谢您的帮助.

如果需要更多代码，我可以显示.

If any more code is required i can show it.

推荐答案

workoutSet.days 是一个无序的集合，因此每次配置单元格时，您都会以随机顺序获取项目.您应该要求 FRC 为您返回 indexPath 的适当对象.

workoutSet.days is a nun-ordered collection so each time you configure a cell you're getting the items in a random order. You should be asking the FRC to return you the appropriate object for the indexPath.

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