NSPredicate有多个参数和"AND行为"

我有一个函数从特定实体中获取满足指定标准的那些对象:

func fetchWithPredicate(entityName: String, argumentArray: [AnyObject]) -> [NSManagedObject] {

    let fetchRequest = NSFetchRequest(entityName: entityName)
    fetchRequest.predicate = NSPredicate(format: "%K == %@", argumentArray: argumentArray)

     do {
         return try self.managedContext.executeFetchRequest(fetchRequest) as! [NSManagedObject]
     } catch {
         let fetchError = error as NSError
         print(fetchError)
         return [NSManagedObject]()
     }

}

当我传递一个包含多个aguments(多个属性名称和值)的数组时,似乎会创建一个这样的查询:

attributeName1 = value1 OR attributeName2 = value2 OR attributeName3 = value3 OR...

我想为AND更改这些OR.

编辑:

问题是它只用"%K ==%@" 替换了前两个项目.

所以,我必须创建一个NSCompoundPredicate来动态创建谓词.

在您的示例中%K,%@格式标记仅由参数数组的前两项替换,其他项将被忽略.

例如,您必须提供要在字符串中替换的所有格式标记

NSPredicate(format: "%K == %@ AND %K == %@", argumentArray:["key1", "value1", "key2", "value2"])

要动态创建谓词(具有可变数量的表达式),请使用NSCompoundPredicate,例如

let predicate = NSCompoundPredicate(andPredicateWithSubpredicates: subPredicates)

where subPredicates是一个[NSPredicate]数组,每个subpredicate都是从循环中提供的参数创建的

NSPredicate(format: "%K == %@", key, value)

像这样(未经测试):

func fetchWithPredicate(entityName: String, argumentArray: [NSObject])  -> [NSManagedObject]  {

    var subPredicates : [NSPredicate] = []
    for i in 0.stride(to: argumentArray.count, by: 2) {
        let key = argumentArray[i]
        let value = argumentArray[i+1]
        let subPredicate = NSPredicate(format: "%K == %@", key, value)
        subPredicates.append(subPredicate)
    }

    let fetchRequest = NSFetchRequest(entityName: entityName)
    fetchRequest.predicate = NSCompoundPredicate(andPredicateWithSubpredicates: subPredicates)

    // ...
}