JAVA 一个类调用另一个类的private方法怎么调？

Question

public class A extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}

public class B{
private void start(){
。。。。。。。。。。
}
}

主类A想调用B类里面的start()方法怎么调用？B是外部类

Answer 1

用反射

    public static void main(String[] args) throws Exception {
        A a = new A();
        a.startB();
    }

    public static class A {
        public void startB() throws Exception {
            Method method;
            method = B.class.getDeclaredMethod("start");
            method.setAccessible(true);
            method.invoke(new B());

        }
    }

    public static class B {
        private void start() {
            System.out.println("B is started.");
        }
    }