领域列表过滤器Swift [英] Realm List Filter Swift

问题描述

var numbersDetail = List is type of ContactDetail()
let predicate = NSPredicate(format: ContactDetail.NUMBER + " = %@", formattedNumber!)
let realmContactDetail = numbersDetail.filter(predicate).first

获取错误:

throw RLMException(此方法只能在RLMArray上调用 从RLMRealm检索到的实例")；

throw RLMException("This method may only be called on RLMArray instances retrieved from an RLMRealm");

推荐答案

如果您尝试对Realm Swift List对象执行查询(实际上是幕后的Objective-C RLMArray对象)，则会发生此错误.在其父对象添加到Realm之前.

This error occurs if you try and perform a query on a Realm Swift List object (Which are actually Objective-C RLMArray objects under the hood) before its parent object has been added to a Realm.

class Person: Object {
  dynamic var name = ""
  dynamic var picture: NSData? = nil // optionals supported
  let dogs = List<Dog>()
}

let dog = Dog()
dog.name = "Rex"

let person = Person()
person.dogs.append(dog)

let rex = person.dogs.filter("name == 'Rex'") // QUERY WILL TRIGGER EXCEPTION AT THIS POINT

let realm = try! Realm()
try! realm.write {
    realm.add(person)
}

let rex = person.dogs.filter("name == 'Rex'") // Query will now work as expected

简而言之，在执行该查询之前，需要确保numbersDetail属于Realm.您可以通过选中numbersDetail.realm != nil轻松地对此进行测试.

In a nutshell, you need to make sure that numbersDetail belongs to a Realm before you perform that query. You can easily test this by checking numbersDetail.realm != nil.

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