ios - RealmSwift : Detach an object from Realm, 包括其列表类型的属性

Question

我想创建一个持久化对象的副本，这样新实例具有所有相同的值但不附加到 Realm。使用 Object(value: persistedInstance) 非常适合属性都是字符串、日期、数字等的类。但是，当复制具有 List 类型属性的类的实例时，副本的 List 和 List 的元素继续引用持久化的记录。我如何创建一个完全脱离 Realm 的副本，包括任何列表和这些列表中的元素？

Answer 1

您可以通过以下扩展函数对您的对象进行深度复制:

    import UIKit
    import Realm
    import RealmSwift
    
    protocol RealmListDetachable {

    func detached() -> Self
}

extension List: RealmListDetachable where Element: Object {

    func detached() -> List<Element> {
        let detached = self.detached
        let result = List<Element>()
        result.append(objectsIn: detached)
        return result
    }

}

@objc extension Object {

    public func detached() -> Self {
        let detached = type(of: self).init()
        for property in objectSchema.properties {
            guard
                property != objectSchema.primaryKeyProperty,
                let value = value(forKey: property.name)
            else { continue }
            if let detachable = value as? Object {
                detached.setValue(detachable.detached(), forKey: property.name)
            } else if let list = value as? RealmListDetachable {
                detached.setValue(list.detached(), forKey: property.name)
            } else {
                detached.setValue(value, forKey: property.name)
            }
        }
        return detached
    }
}

extension Sequence where Iterator.Element: Object {

    public var detached: [Element] {
        return self.map({ $0.detached() })
    }

}

使用

/// in collections
let data = realm.objects(AbcDfg.self).detached

/// single object
data.first?.detached()