我有这堂课:
public class BaseFilterableArrayAdapter<T> extends ArrayAdapter< IFilterableEntity<T> > implements SectionIndexer
{
public BaseFilterableArrayAdapter(Activity context,int id_row_template, List<IFilterableEntity<T>> data)
{
super(context, id_row_template, data);
}
下一个类扩展了前一个类,这是它的构造函数:
public MyAdapter(Activity context, List<MyEntity> data)
{
super(context, R.layout.listview_row, data);
....
}
(MyEntity类实现IFilterableEntity&lt; String&gt;)
问题是我收到了错误
The constructor `BaseFilterableArrayAdapter<String>(Activity, int, List<MyEntity>)` is undefined
如何从 MyAdapter 调用 BaseFilterableArrayAdapter 的构造函数?
答案 0 :(得分:1)
泛型不变,因此List<MyEntity>
与List<IFilterableEntity<T>
的类型不同。您可以使超类本身具有通用性,并使子类包含<MyEntity<T>
泛型类型参数
public class BaseFilterableArrayAdapter<T> extends ArrayAdapter<T>
implements SectionIndexer{
public BaseFilterableArrayAdapter(Activity context, int idRowTemplate, List<T> data) {
super(context, idRowTemplate, data);
...
}
}
答案 1 :(得分:0)
这是一个众所周知的Java痛苦的屁股。请查看以下代码:
import java.awt.List;
import java.util.ArrayList;
class Animal {
}
class Cat extends Animal {
}
public class TemplatedList {
public static void main(String[] args) {
ArrayList<Animal> animals = new ArrayList<Cat>();
}
}
它不会编译:
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
Type mismatch: cannot convert from ArrayList<Cat> to ArrayList<Animal>
at TemplatedList.main(TemplatedList.java:14)
不幸的是,你必须在传递给超级构造函数之前手动转换它。