我想按作者的姓氏对表格进行排序。目前,数据以核心数据中的字符串形式保存为“FirstName LastName”。核心数据 - 可以使用NSSortDescriptor中的块对TableView进行排序?
我知道核心数据中的自定义选择器超出了Cocoa的范围,并返回'NSInvalidArgumentException', reason: 'unsupported NSSortDescriptor selector: compareToLastName:'
这是否也适用于比较器?
下面是我从这个工作似乎完全忽略比较。
// Sort the request
NSSortDescriptor *sortByType;
if ([sort isEqualToString:@"author"]) {
NSComparator comparisonBlock = ^(id obj1,id obj2) {
NSString *obj1B = [[(NSString *)obj1 componentsSeparatedByString:@" "] lastObject];
NSString *obj2B = [[(NSString *)obj2 componentsSeparatedByString:@" "] lastObject];
return (NSComparisonResult) [obj1B compare: obj2B];
};
sortByType = [[NSSortDescriptor alloc] initWithKey:sort ascending:YES comparator:comparisonBlock];
}
else {
sortByType = [[NSSortDescriptor alloc] initWithKey:sort ascending:YES];
}
NSSortDescriptor *secondSort = [[NSSortDescriptor alloc] initWithKey:@"title" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortByType, secondSort, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
谢谢!