我正在学习如何使用kotlin并开始使用tornadoFX。我正在浏览指南以尝试学习它,但是我无法弄清楚具有不同类型的树视图中的含义是什么。似乎我应该使用星形投影,正如我在电话中使用*时所知道的那样。
然而,只要我这样做,树视图就会说'不允许对函数和属性的类型参数进行预测。
这是我的代码:
类MainView:查看(""){
override val root = treeview<*> {
root = TreeItem(Person("Departments", ""))
cellFormat {
text = when (it) {
is String -> it
is Department -> it.name
is Person -> it.name
else -> throw IllegalArgumentException("Invalid Data Type")
}
}
populate { parent ->
val value = parent.value
if (parent == root) departments
else if (value is Department) persons.filter { it.department == value.name }
else null
} }
}
我老老实实地难倒,我不知道自己应该做些什么。
另外,如果其他人可以为我提供一些学习Kotlin和tornadoFX的有用链接,我们将不胜感激:)
答案 0 :(得分:2)
看来指南实际上是不正确的。我使用treeview<Any>
:
data class Department(val name: String)
data class Person(val name: String, val department: String)
val persons = listOf(
Person("Mary Hanes", "Marketing"),
Person("Steve Folley", "Customer Service"),
Person("John Ramsy", "IT Help Desk"),
Person("Erlick Foyes", "Customer Service"),
Person("Erin James", "Marketing"),
Person("Jacob Mays", "IT Help Desk"),
Person("Larry Cable", "Customer Service")
)
val departments = persons.groupBy { Department(it.department) }
override val root = treeview<Any> {
root = TreeItem("Departments")
cellFormat {
text = when (it) {
is String -> it
is Department -> it.name
is Person -> it.name
else -> kotlin.error("Invalid value type")
}
}
populate { parent ->
val value = parent.value
when {
parent == root -> departments.keys
value is Department -> departments[value]
else -> null
}
}
}
答案 1 :(得分:0)
当这篇文章挽救了我的生活时,我以为我想完全放弃tornadofx。就我而言,我想显示一个对象的嵌套列表。我没想到像else -> null
这样的东西可以防止stackoverlow。不知何故,我最终得到了这个填充块,该填充块现在对我有用
populate { parent -> val value = parent.value
when
{
parent == root -> quotation.houses
value is NewHouse -> value.rooms
else -> null
}}