将域模型与 ItemViewModel 中的可为空字段绑定

Question

当运行这段代码时：

class PersonApp : App(PersonView::class)
class Person {
    var name: String? = null
}
class PersonModel: ItemViewModel<Person>() {
    val name = bind(Person::name)
}
class PersonView : View() {
    val model: PersonModel by inject()
    override val root = form {
        textfield(model.name)
    }
}

抛出以下异常：

Nov 26, 2017 12:18:10 PM tornadofx.DefaultErrorHandler uncaughtException
SEVERE: Uncaught error
kotlin.TypeCastException: null cannot be cast to non-null type javafx.beans.property.Property<N>
    at favetelinguis.bfgx.PersonModel$$special$$inlined$bindMutableNullableField.invoke(ViewModel.kt:538)
    at favetelinguis.bfgx.PersonModel$$special$$inlined$bindMutableNullableField.invoke(ViewModel.kt:512)
    at favetelinguis.bfgx.PersonModel.<init>(Exeee.kt:27)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:442)
    at tornadofx.FXKt.find(FX.kt:413)
    at favetelinguis.bfgx.Bree$$special$$inlined$inject.getValue(Component.kt:954)
    at favetelinguis.bfgx.Bree$$special$$inlined$inject.getValue(Component.kt:151)
    at favetelinguis.bfgx.Bree.getModel(Exeee.kt)
    at favetelinguis.bfgx.Bree$root.invoke(Exeee.kt:20)
    at favetelinguis.bfgx.Bree$root.invoke(Exeee.kt:17)
    at tornadofx.FXKt.opcr(FX.kt:454)
    at tornadofx.FormsKt.form(Forms.kt:23)
    at favetelinguis.bfgx.Bree.<init>(Exeee.kt:19)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:442)
    at tornadofx.FXKt.find(FX.kt:413)
    at tornadofx.FXKt.find$default(FX.kt:398)
    at tornadofx.App.start(App.kt:79)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication12(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait5(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null3(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater4(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)

在所有初始值为 null 且要从 GUI 设置的领域模型中，惯用的工作方式是什么？那就是我如何更改上面的代码以使其按预期工作？

Answer 1

这应该已经在 TornadoFX 1.7.13-SNAPSHOT 中工作了，我们对可为空的 POJO 做了一些改进。另一种方法（和更好的 IMO）是在域对象中使用 JavaFX 属性：

class Person {
    val nameProperty = SimpleStringProperty()
    var name by nameProperty
}

最后要考虑的一件事是您尚未在 ViewModel 中设置初始项。请记住，ViewModel 本身不会创建项目的实例，您必须手动执行此操作，甚至在创建时为 ViewModel 提供默认项目：

class PersonModel : ItemViewModel<Person>(Person()) {
    val name = bind(Person::name)
}

将域模型与 ItemViewModel 中的可为空字段绑定

Binding a domain model with nullable fields in ItemViewModel

kotlin

tornadofx