从泛型类型获取类对象

Question

I want to simplify a project by removing useless classes. By useless classes I mean something like :

public class MainPage extends TileGridFragment<MainModel> {}

The whole logic of this class is implemented by TileGridFragment , and the data is provided by MainModel , which instance is accessed thanks to a singleton class.

I want to defer the instanciation of such class to a later time, so I simply pass MainPage.class to my methods.

As MainPage is equivalent to TileGridFragment<MainModel> , I would like to remove this class and instead use something like TileGridFragment<MainModel>.class instead.

But this doesn't work and I'm out of idead.

I've also tried Class.forName , but its throws a ClassNotFoundException .

Any idea ?

Answer 1

If the implementation of MainPage is actually {} , just pass TileGridFragment.class . The actual type parameters are irrelevant on runtime because they are removed by erasure .

Also, because of erasure, you can cast the new TileGridFragment (with a raw type, as the result of TitleGridFragment.class.newInstance() ) to TitleGridFragment<MainModel> , and ther will be no collateral damages (other than a little warning from the compiler, that can be supressed).

Answer 2

You can't really, you might get some joy from reflection but I'm not sure exactly what you're trying to do.

Try here: Get generic type of class at runtime