Question

我创建了一个名为student的课程，我希望使用NSUserDefaults来存储和检索array of student.

//Establish array
var classonestudents = [student] ()
class student {
var name = String ()
var C4Role = 0
var LastTeam = 0
}
//This array is filled up by the user

//Store data
NSUserDefaults.standardUserDefaults().setObject(classonestudents, forKey: "class")

//Retrieve data
classonestudents = NSUserDefaults.standardUserDefaults().objectForKey("class")

我收到错误：Cannot assign value of type 'AnyObject?' to type '[student]'

Answer 1

NSUserDefaults.standardUserDefaults().objectForKey("class")期望AnyObject类型的可选对象。您可以强行打开array of student.

//Retrieve data
classonestudents = NSUserDefaults.standardUserDefaults().objectForKey("class") as! [student]

但你应该经常检查它是否为零：

if let students = NSUserDefaults.standardUserDefaults().objectForKey("class") as? [student]
{
    classonestudents = students
}

Answer 2

只需使用以下代码更改最后一行代码即可修复错误：

classonestudents = NSUserDefaults.standardUserDefaults().objectForKey("class") as! [student]

希望，这会对你有帮助。

使用NSUserDefaults检索对象数组

2 个答案: