class A {
int a;
int b;
int add(){
return a+b;
}
public void seta(int a){this.a=a;}
public void setb(int b){this.b=b;}
}
a和b的值就可以在指定的xml文件裏修改.
抽象成簡單的代碼:
interface Pen{}
class GangBi implements Pen{}
class MaoBi implements Pen{}
class QianBi implements Pen{}
class Human{
void usePen(Pen pen){}
}