GUI：
awt和swing：
java.awt：Abstract Window ToolKit（抽象窗口工具包），需要调用本地系统方法实现功能。属于重量级控件。
javax.swing：在awt的基础上，建立的一套图形界面系统，其中提供了更多的组件，而且完全由Java实现。增强了移植性，属于轻量级控件。
创建图形化界面：
（1）创建Frame窗体；
（2）对窗体进行基本设置。如：大小、位置、布局；
（3）定义组件；
（4）将组件通过窗体的add方法添加到窗体中；
（5）让窗体显示，通过setVisible(true)。
事件监听机制的特点：
（1）事件源
（2）事件
（3）监听器
（4）事件处理
事件源：就是awt包或者swing包中的那些图形界面组件。
事件：每一个事件源都有自己特有的对应事件和共性事件。
监听器：将可以触发某一个事件的动作（不止一个）都封装到了监听器中。
以上三者，在Java中都定义好了，直接获取其对象来用就可以。我们只要对产生的动作进行处理。
1 import java.awt.Button;
2 import java.awt.FlowLayout;
3 import java.awt.Frame;
4 import java.awt.event.ActionEvent;
5 import java.awt.event.ActionListener;
6 import java.awt.event.WindowAdapter;
7 import java.awt.event.WindowEvent;
8
9 public class Demo{
10 //定义该图形中的所需组件的引用
11 private Frame f;
12 private Button b;
13 Demo(){
14 init();
15 }
16 public void init(){
17 f = new Frame("my frame");
18
19 //对frame进行基本设置
20 f.setBounds(300, 200, 300, 200);
21 f.setLayout(new FlowLayout());
22
23 b = new Button("按钮");
24
25 //将组件添加到frame中
26 f.add(b);
27
28 //加载一下窗体上的事件
29 myEvent();
30
31 //显示窗体
32 f.setVisible(true);
33 }
34 private void myEvent(){
35 f.addWindowListener(new WindowAdapter(){
36 public void windowClosing(WindowEvent e){
37 System.exit(0);
38 }
39 });
40
41 //让按钮具备退出程序的功能
42 //此时按钮就是事件源，想要知道哪个组件具备什么样的特有监听器，需要查看该组件对象的功能，通过查阅button的描述，
43 //发现按钮支持一个特有监听addActionListener
44 b.addActionListener(new ActionListener(){
45 public void actionPerformed(ActionEvent e){
46 System.exit(0);
47 }
48 });
49 }
50 public static void main(String[] args){
51 new Demo();
52 }
53 }
鼠标事件：
1 import java.awt.Button;
2 import java.awt.FlowLayout;
3 import java.awt.Frame;
4 import java.awt.event.MouseAdapter;
5 import java.awt.event.MouseEvent;
6 import java.awt.event.WindowAdapter;
7 import java.awt.event.WindowEvent;
8
9 public class Demo{
10 private Frame f;
11 private Button b;
12 Demo(){
13 init();
14 }
15 public void init(){
16 f = new Frame("my frame");
17
18 f.setBounds(300, 200, 300, 200);
19 f.setLayout(new FlowLayout());
20
21 b = new Button("按钮");
22
23 f.add(b);
24
25 myEvent();
26
27 f.setVisible(true);
28 }
29 private void myEvent(){
30 f.addWindowListener(new WindowAdapter(){
31 public void windowClosing(WindowEvent e){
32 System.exit(0);
33 }
34 });
35 b.addMouseListener(new MouseAdapter(){
36 public void mouseEntered(MouseEvent e){
37 System.out.println("鼠标进入该组件");
38 }
39
40 public void mouseClicked(MouseEvent e){
41 if(e.getClickCount() == 2)
42 System.out.println("双击动作");
43 }
44 });
45 }
46 public static void main(String[] args){
47 new Demo();
48 }
49 }
键盘事件：
1 import java.awt.Button;
2 import java.awt.FlowLayout;
3 import java.awt.Frame;
4 import java.awt.TextField;
5 import java.awt.event.KeyAdapter;
6 import java.awt.event.KeyEvent;
7 import java.awt.event.WindowAdapter;
8 import java.awt.event.WindowEvent;
9
10 public class Demo{
11 private Frame f;
12 private Button b;
13 private TextField tf;
14 Demo(){
15 init();
16 }
17 public void init(){
18 f = new Frame("my frame");
19
20 f.setBounds(300, 200, 300, 200);
21 f.setLayout(new FlowLayout());
22
23 tf = new TextField(20);
24
25 b = new Button("按钮");
26
27 f.add(b);
28 f.add(tf);
29
30 myEvent();
31
32 f.setVisible(true);
33 }
34 private void myEvent(){
35 f.addWindowListener(new WindowAdapter(){
36 public void windowClosing(WindowEvent e){
37 System.exit(0);
38 }
39 });
40
41 //添加键盘监听
42 b.addKeyListener(new KeyAdapter(){
43 // public void keyPressed(KeyEvent e){
44 // //按“ESC”键，程序退出
45 // if(e.getKeyCode() == KeyEvent.VK_ESCAPE)
46 // System.exit(0);
47 // }
48
49 //Ctrl+回车键，使程序退出
50 public void keyPressed(KeyEvent e){
51 if(e.isControlDown() && e.getKeyCode() == KeyEvent.VK_ENTER)
52 System.exit(0);
53 }
54 });
55
56 //设置文本框，使它只能被输入数字
57 tf.addKeyListener(new KeyAdapter(){
58 public void keyPressed(KeyEvent e){
59 int code = e.getKeyCode();
60 if(!(code >= KeyEvent.VK_0 && code <= KeyEvent.VK_9)){
61 System.out.println(code + "...是非法的");
62 e.consume();
63 }
64 }
65 });
66 }
67 public static void main(String[] args){
68 new Demo();
69 }
70 }
例：列出指定目录内容：
1 import java.awt.Button;
2 import java.awt.Dialog;
3 import java.awt.FlowLayout;
4 import java.awt.Frame;
5 import java.awt.Label;
6 import java.awt.TextArea;
7 import java.awt.TextField;
8 import java.awt.event.ActionEvent;
9 import java.awt.event.ActionListener;
10 import java.awt.event.KeyAdapter;
11 import java.awt.event.KeyEvent;
12 import java.awt.event.WindowAdapter;
13 import java.awt.event.WindowEvent;
14 import java.io.File;
15
16 public class Demo{
17 private Frame f;
18 private Button b;
19 private TextField tf;
20 private TextArea ta;
21 private Dialog d;
22 private Label label;
23 private Button okBut;
24 Demo(){
25 init();
26 }
27 public void init(){
28 f = new Frame("练习");
29 f.setBounds(300, 100, 600, 500);
30 f.setLayout(new FlowLayout());
31
32 b = new Button("转到");
33
34 tf = new TextField(60);
35 ta = new TextArea(25, 70);
36
37 //参数为true，表明必须先操作Dialog
38 d = new Dialog(f, "提示信息-self", true);
39 d.setBounds(400, 200, 240, 150);
40 d.setLayout(new FlowLayout());
41 label = new Label();
42 okBut = new Button("确定");
43 d.add(label);
44 d.add(okBut);
45
46 f.add(tf);
47 f.add(b);
48 f.add(ta);
49
50 myEvent();
51
52 f.setVisible(true);
53 }
54 public void myEvent(){
55 f.addWindowListener(new WindowAdapter(){
56 public void windowClosing(WindowEvent e){
57 System.exit(0);
58 }
59 });
60
61 b.addActionListener(new ActionListener(){
62 public void actionPerformed(ActionEvent e){
63 showDir();
64 }
65 });
66
67 d.addWindowListener(new WindowAdapter(){
68 public void windowClosing(WindowEvent e){
69 d.setVisible(false);
70 }
71 });
72
73 okBut.addActionListener(new ActionListener(){
74 public void actionPerformed(ActionEvent e){
75 d.setVisible(false);
76 }
77 });
78
79 tf.addKeyListener(new KeyAdapter(){
80 public void keyPressed(KeyEvent e){
81 if(e.getKeyCode() == KeyEvent.VK_ENTER){
82 showDir();
83 }
84 }
85 });
86 }
87
88 private void showDir(){
89 String dirPath = tf.getText();
90 File file = new File(dirPath);
91 if(file.exists() && file.isDirectory()){
92 tf.setText("");
93 String[] names = file.list();
94 for(String name : names){
95 ta.append(name + "\r\n");
96 }
97 }
98 else{
99 String info = "您输入的信息: " + dirPath + "是错误的。请重新输入！";
100 label.setText(info);
101 d.setVisible(true);
102 }
103 }
104
105 public static void main(String[] args) {
106 new Demo();
107 }
108 }
菜单：
1 import java.awt.FlowLayout;
2 import java.awt.Frame;
3 import java.awt.Menu;
4 import java.awt.MenuBar;
5 import java.awt.MenuItem;
6 import java.awt.event.ActionEvent;
7 import java.awt.event.ActionListener;
8 import java.awt.event.WindowAdapter;
9 import java.awt.event.WindowEvent;
10
11 public class Demo{
12 private Frame f;
13 private MenuBar mb;
14 private Menu m, subMenu;
15 private MenuItem closeItem, subItem;
16
17 Demo(){
18 init();
19 }
20
21 public void init(){
22 f = new Frame("my window");
23 f.setBounds(300, 100, 500, 600);
24 f.setLayout(new FlowLayout());
25
26 mb = new MenuBar();
27
28 m = new Menu("文件");
29 subMenu = new Menu("子菜单");
30 closeItem = new MenuItem("退出");
31 subItem = new MenuItem("子条目");
32
33 subMenu.add(subItem);
34 m.add(subMenu);
35 m.add(closeItem);
36 mb.add(m);
37 f.setMenuBar(mb);
38
39 myEvent();
40
41 f.setVisible(true);
42 }
43
44 public void myEvent(){
45 f.addWindowListener(new WindowAdapter(){
46 public void windowClosing(WindowEvent e){
47 System.exit(0);
48 }
49 });
50
51 closeItem.addActionListener(new ActionListener(){
52 public void actionPerformed(ActionEvent e){
53 System.exit(0);
54 }
55 });
56
57 }
58
59 public static void main(String[] args) {
60 new Demo();
61 }
62 }
如图：
打开保存文件：
1 import java.awt.FileDialog;
2 import java.awt.Frame;
3 import java.awt.Menu;
4 import java.awt.MenuBar;
5 import java.awt.MenuItem;
6 import java.awt.TextArea;
7 import java.awt.event.ActionEvent;
8 import java.awt.event.ActionListener;
9 import java.awt.event.WindowAdapter;
10 import java.awt.event.WindowEvent;
11 import java.io.BufferedReader;
12 import java.io.BufferedWriter;
13 import java.io.File;
14 import java.io.FileReader;
15 import java.io.FileWriter;
16 import java.io.IOException;
17
18 public class Demo{
19 private Frame f;
20 private Menu fileMenu;
21 private MenuItem openItem, saveItem, closeItem;
22 private MenuBar bar;
23 private FileDialog openD, saveD;
24 private TextArea ta;
25 private File file;
26 Demo(){
27 init();
28 }
29
30 public void init(){
31 f = new Frame("练习");
32 f.setBounds(300, 100, 650, 600);
33
34 bar = new MenuBar();
35 ta = new TextArea();
36 openItem = new MenuItem("打开");
37 saveItem = new MenuItem("保存");
38 closeItem = new MenuItem("退出");
39 fileMenu = new Menu("文件");
40
41 fileMenu.add(openItem);
42 fileMenu.add(saveItem);
43 fileMenu.add(closeItem);
44 bar.add(fileMenu);
45 f.setMenuBar(bar);
46 f.add(ta);
47
48 openD = new FileDialog(f, "打开文件", FileDialog.LOAD);
49 saveD = new FileDialog(f, "保存文件", FileDialog.SAVE);
50
51 myEvent();
52
53 f.setVisible(true);
54 }
55
56 public void myEvent(){
57 //窗口关闭
58 f.addWindowListener(new WindowAdapter(){
59 public void windowClosing(WindowEvent e){
60 System.exit(0);
61 }
62 });
63
64 //点击“退出”条目，退出程序
65 closeItem.addActionListener(new ActionListener(){
66 public void actionPerformed(ActionEvent e){
67 System.exit(0);
68 }
69 });
70
71 //打开选中的文件，显示在TextArea中
72 openItem.addActionListener(new ActionListener(){
73 public void actionPerformed(ActionEvent e){
74 openD.setVisible(true);
75 String dirPath = openD.getDirectory();
76 String fileName = openD.getFile();
77 if(dirPath == null || fileName == null)
78 return;
79 ta.setText("");
80 file = new File(dirPath, fileName);
81 try{
82 BufferedReader bufr = new BufferedReader(new FileReader(file));
83 String line = null;
84 while((line = bufr.readLine()) != null){
85 ta.append(line + "\r\n");
86 }
87 }catch(IOException ex){
88 throw new RuntimeException("读取失败！");
89 }
90
91 }
92 });
93
94 //保存文件
95 saveItem.addActionListener(new ActionListener(){
96 public void actionPerformed(ActionEvent e){
97 if(file == null){
98 saveD.setVisible(true);
99 String dirPath = openD.getDirectory();
100 String fileName = openD.getFile();
101 if(dirPath == null || fileName == null)
102 return;
103 file = new File(dirPath, fileName);
104 }
105 try{
106 BufferedWriter bufw = new BufferedWriter(new FileWriter(file));
107 String s = ta.getText();
108 bufw.write(s);
109 bufw.flush();
110 bufw.close();
111 }catch(IOException ex){
112 throw new RuntimeException("保存失败！");
113 }
114 }
115 });
116
117 }
118
119 public static void main(String[] args) {
120 new Demo();
121 }
122 }
时间： 2024-10-16 18:04:44