Swift 4.2 中的 NSSortDescriptor 区分大小写

Question

我正在尝试使用 NSSortDescriptor 不区分大小写按字母顺序排序是 Swift 4.2。不幸的是，我只在 Objective-C 中找到了解决方案。

func fetchRequest() -> NSFetchRequest<NSFetchRequestResult> {

    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Entity")
    let sorter = NSSortDescriptor(key: "texttitle", ascending: true)

    fetchRequest.sortDescriptors = [sorter]
    return fetchRequest

}

Answer 1

使用caseInsensitiveCompare:(带冒号)在 Swift 4.2 中不起作用。

这个有效:

func fetchRequest() -> NSFetchRequest<NSFetchRequestResult> {

    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Entity")
    let sorter = NSSortDescriptor(key: "texttitle", ascending: true, selector: #selector(NSString.caseInsensitiveCompare))

    fetchRequest.sortDescriptors = [sorter]
    return fetchRequest

}