swift - 如何使我的排序功能真正在表格 View 中显示排序后的书籍

Question

您好，尝试使用 CocoaPods Dropdown 创建一个排序按钮，代码没有显示任何错误，菜单也可以工作，但如果我单击该按钮，则什么也没有发生。

    dropDown.selectionAction = { [weak self] (index: Int, item: String) in //8
      guard let _ = self else { return }
      sender.setTitle(item, for: .normal) //9
       
        let realm = try! Realm()
        var books = realm.objects(Book.self).sorted(byKeyPath: "title", ascending: false)
    
        if item == "sort by author" {
            func filterResultsbyauthor(searchString: String){
                 let predicate = NSPredicate(format: "author BEGINSWITH [c]%@", searchString)
                books = realm.objects(Book.self).filter(predicate).sorted(byKeyPath:"author", ascending: true)
                self?.tableview.reloadData()
            }
        }
    }

Answer 1

错误可能在这里:

func filterResultsbyauthor(searchString: String){
    let predicate = NSPredicate(format: "author BEGINSWITH [c]%@", searchString)
    books = realm.objects(Book.self).filter(predicate).sorted(byKeyPath:"author", ascending: true)
    self?.tableview.reloadData()
}

您定义了一个函数，但从未调用过它。

您可以:

1. 调用函数

func filterResultsbyauthor(searchString: String){
    let predicate = NSPredicate(format: "author BEGINSWITH [c]%@", searchString)
    books = realm.objects(Book.self).filter(predicate).sorted(byKeyPath:"author", ascending: true)
    self?.tableview.reloadData()
}

filterResultsbyauthor(searchString: "Your search string") /// here!

删除函数声明并使其成为一段代码

let predicate = NSPredicate(format: "author BEGINSWITH [c]%@", "Your search string")
books = realm.objects(Book.self).filter(predicate).sorted(byKeyPath:"author", ascending: true)
self?.tableview.reloadData()