Re: [問題] 不同class之間的傳值取用

[qrtt1 (愚者)]

==站內信件==

轉信又不正常了>"<
只好重po了
===============================================================

這不會沒深度啊:)
這看起來很適合使用觀察者模式
也剛好java本身就有這樣的工具呦

我試著依您的架構寫了一個sample

A_________________________________________________
import java.util.Observable;

public class A extends Observable{
       int x = 0;
       int y = 0;

       public A() {
       }

       private void changeLocation(int x, int y){
               this.x += x;
               this.y += y;

               // mark data have been changed
               setChanged() ;

               // notify observer
               notifyObservers();

       }

       public void up() {
               System.out.println("Up");
           this.changeLocation(0,1);
       }

       public void down() {
               System.out.println("Down");
               this.changeLocation(0,-1);
       }


       public void left() {
               System.out.println("Left");
               this.changeLocation(-1,0);
       }

       public void right() {
               System.out.println("Right");
               this.changeLocation(1,0);
       }
}

B__________________________________________________
import java.util.Observable;
import java.util.Observer;

public class B implements Observer {
       private int x;

       private int y;

       public B(Observable o) {
               o.addObserver(this);
       }

       public void update(Observable o, Object arg) {
               if (o instanceof A) {
                       A a = (A) o;
                       this.x = a.x;
                       this.y = a.y;
               }
               display();
       }

       public void display() {
               System.out.println("X: " + x);
               System.out.println("Y: " + y);
       }
}

TestIt______________________________________________________
import java.util.Random;

public class TestIt {
       public static void main(String[] args) {
               A playDevice = new A();
               B display = new B(playDevice);

               Random r = new Random();

               for (int i = 0; i < 10; i++)
                       switch (r.nextInt() % 4) {
                       case 0:
                               playDevice.up();
                               break;
                       case 1:
                               playDevice.down();
                               break;
                       case 2:
                               playDevice.right();
                               break;
                       case 3:
                               playDevice.left();
                               break;
                       }


       }
}

==================================================

Up
X: 0
Y: 1
Up
X: 0
Y: 2
Up
X: 0
Y: 3
Left
X: -1
Y: 3
Right
X: 0
Y: 3
Up
X: 0
Y: 4
Left
X: -1
Y: 4
Up
X: -1
Y: 5
Down
X: -1
Y: 4

--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 163.26.34.105
※ 編輯: qrtt1           來自: 163.26.34.105        (07/14 04:42)