Question

我正在寻找在函数中从coredata读取数据的最佳方法，并在事后循环结果。

我已经尝试了很多方法，但似乎想要了解每个对象中的特定数据片段。

这是我的设置。

    func readData()->NSArray{
    let entityName:String = "Properties"
    let appDel:AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
    let context:NSManagedObjectContext = appDel.managedObjectContext

    // Specify what this will be working with
    let request = NSFetchRequest(entityName: entityName)

    // This will return instance of the object needed. Without which this would be
    // a pain to work with. This bit saves a few steps.
    request.returnsObjectsAsFaults = false;

    // Get the data and put it into a variable
    var results = context.executeFetchRequest(request, error: nil)

    return results!
}

我在这里称呼它。

var properties = Properties()
    var getInfo = properties.readData()
    println(getInfo)

    for eachInfo:AnyObject in getInfo{
        println(eachInfo)
    }

那就是这样的东西......

<NSManagedObject: 0x7f87fa711d60> (entity: Properties; id: 0xd000000000040000 <x-coredata://F627AD12-3CEC-4117-8294-616ADEE068DC/Properties/p1> ; data: {
acreage = 0;
conditionId = 0;
contactBusinessName = nil;
contactEmail = nil;
contactName = Bob;
contactPhoneNumber = 456456456;
isFav = nil;
latitude = 0;
longitude = 0;
price = 0;
propertyCity = nil;
propertyId = nil;
propertyState = nil;
propertyStreetAddress = nil;
propertyType = 0;
propertyZip = nil;
squareFeet = 0;
year = 0;

}）

这很棒。但是当我使用下面的代码访问其中的数据时....

for eachInfo:AnyObject in getInfo{
        println(eachInfo.contactName)
    }

我收到以下错误。

＆＃34;＆＃39; AnyObject＆＃39;没有名为＆＃39; contactName＆＃39;＆＃34;
的成员

我确信我遗漏了一些简单的东西，但我无法在网上找到它。

非常感谢任何协助甚至更好的方式。

回答。

首先，将名称空间添加到核心数据对象。 http://i.stack.imgur.com/qNNLo.png

其次，强烈键入函数的输出，以便将数据输入到自定义对象。在这种情况下，它被称为＆＃34;属性＆＃34;。

    func readData()->Array<Properties>{


    let appDel:AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
    let context:NSManagedObjectContext = appDel.managedObjectContext

    // Specify what this will be working with
    let request = NSFetchRequest(entityName: entityName)

    // This will return instance of the object needed. Without which this would be
    // a pain to work with. This bit saves a few steps.
    request.returnsObjectsAsFaults = false;

    // Get the data and put it into a variable
    var results = context.executeFetchRequest(request, error: nil)

    return results! as Array<Properties>


}

最后，调用函数并循环数据。

       var properties = Properties()
    var getInfo = properties.readData()

    for eachInfo in getInfo{

        println(eachInfo.contactName)

    }

Answer 1

尝试

func readData()->Array<Properties>{
    let entityName:String = "Properties"
    let appDel:AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
    let context:NSManagedObjectContext = appDel.managedObjectContext

    // Specify what this will be working with
    let request = NSFetchRequest(entityName: entityName)

    // This will return instance of the object needed. Without which this would be
    // a pain to work with. This bit saves a few steps.
    request.returnsObjectsAsFaults = false;

   // Get the data and put it into a variable
   var results = context.executeFetchRequest(request, error: nil)

   return results! as Array<Properties>
}

var getInfo:Array<Properties> = properties.readData()
println(getInfo)

for eachInfo in getInfo{
    println(info.contactName)

}

我这里没有Mac，但我很确定这样的事情。这样就可以获得强类型数据。

Answer 2

找到它。

当将结果作为NSArray传回时，需要将其转换为NSManageObject类。

因此，在回报中正确调用和显示单条信息就像这样。

var properties = Properties()
    var getInfo = properties.readData()
    println(getInfo)

    for eachInfo:AnyObject in getInfo{

        // Cast AnyObject type into the equavalent NSManagedObject.  
        let info = eachInfo as Properties
        println(info.contactName)

    }

＆＃39; AnyObject＆＃39;没有名为＆＃39; contactName＆＃39;的成员阻止我的循环

2 个答案: