Java Swing intro

如果有Android app開發經驗，快速上手Swing不是問題。UI方面有相似的地方。

簡單的幾行代碼就能抛出一個框框，記錄一下操作過程

1.先顯示一個框框

EraseBlockGame類是主類，包含了main入口，繼承自 JFrame

public class EraseBlockGame extends JFrame{
......
    public EraseBlockGame(String GameTitle){  // 構造方法
        super(GameTitle);
        setSize(408, 640);
        setLocationRelativeTo(null);// place in the center of screen 
        ......
        setVisible(true);
    }
}           

設定視窗大小，設定視窗在螢幕上的位置，視窗可見

public static void main(String args[]){
        EraseBlockGame e = new EraseBlockGame("Erase Block Game");
    }           

運作一下程式，彈出一個視窗；視窗名稱為Erase Block Game

2.菜單欄

菜單欄有菜單按鈕，以及菜單選項

import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;           

• JMenuBar 是整個菜單
• JMenu 是菜單欄上的單個按鈕
• JMenuItem 點開單個餐單鍵，彈出的子選項item

public class EraseBlockGame extends JFrame{
    private static final long serialVersionUID = 1L;
    private JMenuBar menuBar = new JMenuBar();
    private JMenu mGame = new JMenu("Game");
    private JMenuItem miNewGame = new JMenuItem("New game");
    private JMenuItem miExit = new JMenuItem("Exit");
    ......
}           

如果多幾個選項，總是new似乎不大好，用簡單工廠來代替new

定義JMenuFactory，裡面有建立JMenu的方法

package com.rust.util;

import javax.swing.JMenu;

public class JMenuFactory {
    JMenu menu;
    public JMenuFactory(){
        
    }
    public JMenu createMenu(String title){
        JMenu menu = new JMenu(title);
        return menu;
    }
}           

同樣定義JMenuItemFactory

package com.rust.util;

import javax.swing.JMenuItem;

public class JMenuItemFactory {
    JMenuItem item;
    public JMenuItemFactory(){
        
    }
    public JMenuItem createMenuItem(String title){
        item = new JMenuItem(title);
        return item;
    }
}           

原來的new就可以替換為

private JMenu mGame;
    private JMenu mControl;
    private JMenu mInfo;
    private JMenuItem miNewGame;
    private JMenuItem miExit;
    ......
        mGame = menuFactory.createMenu("Game");
        mControl = menuFactory.createMenu("Control");
        mInfo = menuFactory.createMenu("Info");
        miNewGame = miFactory.createMenuItem("New game");
        miExit = miFactory.createMenuItem("Exit");           

在構造函數中給菜單item添加ActionListener，和Android app的Button差不多

miNewGame.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                
            }
        });
        miExit.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });
        
        mGame.add(miNewGame);//這裡添加的順序就是排列的順序
        mGame.add(miExit);//往menu中添加子項

        menuBar.add(mGame);
        menuBar.add(mControl);//這裡添加的順序就是排列的順序
        
        setJMenuBar(menuBar);           

如此看來，Swing活在了Android中

3.放置按鈕

此時界面上隻有一些菜單按鍵，多擺幾個按鈕上去看看

定義一個控制台類ControlBoard 繼承自 JPanel

/**
 * 控制台，提供很多快捷的控制功能
 * @author Rust Fisher
 */
public class ControlBoard extends JPanel{
    private JButton btnStart;
    private JButton btnStop;
    private JButton btnPause;
    private JButton btnReset;
    private JButton btnExit;
    /*定義一個按鈕區域areaButton，用來存放btn*/
    private JPanel areaButton = new JPanel(new GridLayout(5, 1));
    
    private EraseBlockGame game;
    /*按鈕區域的框框*/
    private Border border = new EtchedBorder(EtchedBorder.RAISED, Color.WHITE,Color.gray);
    
    public ControlBoard(final EraseBlockGame game){
        setLayout(new GridLayout(3,1,0,1));
        this.game = game;//用于控制
        
        btnStart = new JButton("Start");
        btnStart.setEnabled(true);
        btnStop = new JButton("Stop");
        btnStop.setEnabled(false);
        btnPause = new JButton("Pause");
        btnPause.setEnabled(false);
        btnReset = new JButton("Reset");
        btnReset.setEnabled(true);
        btnExit = new JButton("Exit");
        btnExit.setEnabled(true);
        
        areaButton.add(btnStart);
        areaButton.add(btnPause);
        areaButton.add(btnStop);
        areaButton.add(btnReset);
        areaButton.add(btnExit);
        
        areaButton.setBorder(border);
        
        add(areaButton);// 把按鈕區添加到控制台上
        btnStart.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                // go go go
                
            }
        });
        btnExit.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.exit(0);//886
            }
        });
    }
......
}           

在EraseBlockGame類裡加載按鈕區域

public class EraseBlockGame extends JFrame{
......
    private ControlBoard controlBoard;
    
    public EraseBlockGame(String title){
        ......
        Container container = getContentPane();
        controlBoard = new ControlBoard(this);
        container.add(controlBoard, BorderLayout.EAST);//添加控制台
        ......
    }
}           

于是按鈕就被裝到程式上了

其他的就先不糾結了，Swing了解個大概就好；可以多看看android開發