Question

我有一个通用功能将对象保存到我的领域存储中。 Realm中不在该列表中的现有对象应删除。我如何一般地获取所有相同类型的现有对象？

这是我目前的做法：

  private func determineOrphans(remoteObjects: [Object])->[Object]?{

    guard let remoteObject = remoteObjects.first else {
        return nil
    }

    guard let localObjects = try? queryObjects(with: type(of: remoteObject) ) else{
        return nil
    }
    let allLocalObjectsSet = Set(localObjects.toArray())
    let objectsToDelete = Array(allLocalObjectsSet.subtracting(remoteObjects))
    logger.info("These \(objectsToDelete.count) objects should be deleted: \(objectsToDelete)")
    return objectsToDelete
}

private func queryObjects<T: Object>(with type: T.Type) throws -> Results<T> {
    return try Realm().objects(T.self)
}

Answer 1

这是我获取领域对象的通用函数。

    import RealmSwift

    func queryObjects<T: Object>(with type: T.Type) throws -> Results<T> {
        let realm = try Realm()
        return realm.objects(T.self)
    }

在Realm返回带有延迟加载对象的类型结果的情况下，如果需要模型数组的用法示例：

        do {
            let objects = try queryObjects(with: Model.self).map { $0 }
        } catch {
            print("Can not get Model: \(error)")
        }
    }

更新，此处是determineOrphans的完全通用功能：

    private func determineOrphans<T: Object>(remoteObjects: [T]) -> [T] {
        guard let localObjects = try? queryObjects(with: T.self ) else {
            return []
        }

        let objectsToDelete = localObjects.filter { !remoteObjects.contains($0) }
        logger.info("These \(objectsToDelete.count) objects should be deleted: \(objectsToDelete)")
        return objectsToDelete.map { $0 }
    }

RealmSwift：查询相同泛型的所有对象

1 个答案: