I have a class:
open data class Person(var name: String)
and another class:
data class Student(var reg: String) : Person("")
this gives me an error that:
错误:修饰符"打开"与"数据"不兼容
如果我从Person类中删除数据，那就没问题了.
why kotlin open and data incompatible?
I have a class:
open data class Person(var name: String)
and another class:
data class Student(var reg: String) : Person("")
this gives me an error that:
错误:修饰符"打开"与"数据"不兼容
如果我从Person类中删除数据，那就没问题了.
why kotlin open and data incompatible?
从https://kotlinlang.org/docs/reference/data-classes.html:
To ensure consistency and meaningful behavior of the generated code, data classes have to fulfil the following requirements:
- 主构造函数需要至少有一个参数；
- All primary constructor parameters need to be marked as val or var;
- 数据类不能是抽象的、open的、密封的或内部的；
- (1.1之前)数据类只能实现接口.
所以主要的一点是数据类有一些生成的代码(equalshashCodecopytoStringcomponentN函数).这样的代码不能被程序员 destruct .因此，数据类有一些限制.