Cocoa 自定义NSMangeObject访问器崩溃NSOutlineView

我认为这是核心数据中的一个bug，但在我提交bug报告之前，我想确定这不仅仅是我的愚蠢

我设置了一个NSOutlineView来访问5个不同核心数据实体的数据。每个实体的数据都通过绑定到实体及其“ManagedObjectContext”的不同NSArrayController进行访问。然后，我让NSOutlineViewDataSource方法根据展开的实体返回正确的NSString对象

注：实体在别处声明为NSArray，并带有实体名称

- (id)outlineView:(NSOutlineView *)outlineView child:(NSInteger)index
       ofItem:(id)item {

if(nil == item) {
    return [entities objectAtIndex:index];
}
NSInteger entityIdx = [entities indexOfObject:item];
if (entityIdx == NSNotFound) {
    return @"";
}
id returnObject = @"";
switch (entityIdx) {
    case 0: {
        Person *person  = [[peopleArrayController arrangedObjects] objectAtIndex:index];
        returnObject = person.fullName;
        break;
    }
    case 1: {
        Media *media = [[mediaArrayController arrangedObjects] objectAtIndex:index];
        returnObject = media.imageTitle;
        break;
    }
    case 2: {
        Note *note  = [[notesArrayController arrangedObjects] objectAtIndex:index];
        returnObject = note.noteDescription;
        break;
    }
    case 3: {
        Source *source = [[sourcesArrayController arrangedObjects] objectAtIndex:index];
        returnObject = source.title;
        break;
    }
    case 4: {
        Repository *repo = [[repostioriesArrayController arrangedObjects] objectAtIndex:index];
        returnObject = repo.name;
        break;
    }
    default:
        break;
}


return returnObject;

}

Person实体属性fullName和Media实体属性imageTitle是自定义访问器

- (NSString *)fullName {
[self willAccessValueForKey:@"surName"];
[self willAccessValueForKey:@"givenName"];
NSString *firstName = [self valueForKey:@"givenName"];
NSString *lastName = [self valueForKey:@"surName"];
NSString *string = [NSString stringWithFormat:@"%@ %@", (firstName) ? firstName : @"", (lastName) ? lastName : @""];
[self didAccessValueForKey:@"surName"];
[self didAccessValueForKey:@"givenName"];
return string;

}

}

当我试图展开人物或媒体实体时，程序正在崩溃，但当我展开其他实体时，程序没有崩溃。我将崩溃跟踪到[NSCell\u setContents:][NSObject（NSObject）doesNotRecognizeSelector:]

我将要返回的媒体属性更改为标准核心数据访问器属性@“path”，扩展媒体实体时程序停止崩溃。因此，问题肯定与自定义访问器有关

仅供参考-我检查以确保实体设置为使用NSManagedObject类

---

除了一个bug，谁能给我一个崩溃的原因吗？

我通过改变方法解决了这个问题

-（id）outlineView:（NSOutlineView*）outlineView子项：（NSInteger）项的索引：（id）项

返回托管对象的步骤

case 1: {
        Media *media = [[mediaArrayController arrangedObjects] objectAtIndex:index];
        returnObject = media;
        break;
    }

那我有办法了

-（id）outlineView:（NSOutlineView*）outlineView objectValueForTableColumn:（NSTableColumn*）tableColumn by item:（id）item

返回字符串

    if ([item isKindOfClass:[Media  class]]) {
    Media *media = (Media *)item;
    return media.imageTitle;
}

---

它没有与行returnObject=media.path崩溃；但它确实在returnObject=[media.path lastPathComponent]行中崩溃了；

    if ([item isKindOfClass:[Media  class]]) {
    Media *media = (Media *)item;
    return media.imageTitle;
}