无法在iOS中的Realm数据库中存储Double值

Question

我只是想了解Realm并遇到了一个问题.我有这样的模特

class Template: Object {
    dynamic var id = NSUUID().UUIDString
    var pages = List<TemplatePage>()
}
class TemplatePage : Object {
    var xPosition: Double = 0.0
    var yPosition: Double = 0.0
}

现在,我正在执行以下代码:

class ViewController: UIViewController {

    let realm = try! Realm()
    var templatePages = [TemplatePage]()
    override func viewDidLoad() {
        super.viewDidLoad()

        addTemplatePage(1.0, yPosition: 2.0)

        //add more template pages
        //[...]
        //when all pages have been added create a template out of it.
        addTemplate()
        getXCoordinateOfFirstTemplatePage()


    }

    //Execute this method several times depending on the user interation
    //here we only execute it once
    func addTemplatePage(xPosition: Double, yPosition: Double) {

        do {
            let templatePage = TemplatePage()
            templatePage.xPosition = xPosition
            templatePage.yPosition = yPosition
            try realm.write {
                realm.add(templatePage)
            }

            templatePages.append(templatePage)
        }
        catch _ {
            print("error while adding a template page")
        }
    }
    //once all pages have been added create a template of of all recently added pages
    func addTemplate() {
        do {
            let template = Template()
            try realm.write {

                template.pages.appendContentsOf(templatePages)
                realm.add(template)
            }
        }
        catch _ {
            print("error while adding the template")
        }
    }    
    func getXCoordinateOfFirstTemplatePage() {
        let template = realm.objects(Template)[0]
        print(template.pages[0].xPosition)
    }
}

当我运行此代码时,它会输出0.0,即TemplatePage xPosition属性的默认值.但是,我不明白为什么,因为我真的希望它打印1.0.我不明白为什么.有人能给我一个暗示吗？

Answer 1

我遇到了类似的问题.每当你使用嵌套类时就像使用TemplatePage变量动态一样.

更改

var xPosition: Double = 0.0
var yPosition: Double = 0.0

至

dynamic var xPosition: Double = 0.0
dynamic var yPosition: Double = 0.0