Java学习笔记——图形化界面GUI
GUI
- 框架图
- 监听器与事件
-
- 鼠标事件
- 键盘事件
- 布局
- Frame
- Button
-
- 规范写法
- Dialog
- MenuBar
代码：
框架图
具体方法参见：Jdk13_API
监听器与事件
在代码中表现为：addXxxListener()方法、XxxEvent类。
鼠标事件
package test;
import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class MouseDemo {
private Frame f;
private Button b;
MouseDemo(){
init();
}
//初始化函数
public void init() {
f = new Frame("My Window");
b = new Button("click");
f.setBounds(550, 250, 500, 300);
f.setLayout(new FlowLayout());
f.add(b);
myEvents();
f.setVisible(true);
}
private void myEvents() {
f.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
//添件鼠标事件
f.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
// if(e.getClickCount()==2 && e.getButton()==MouseEvent.BUTTON1) {
// System.out.println("鼠标左键双击动作");
// }else if(e.getClickCount()==1 && e.getButton()==MouseEvent.BUTTON1) {
// System.out.println("鼠标左键单击动作");
// }else if(e.getClickCount()==1 && e.getButton()==MouseEvent.BUTTON3) {
// System.out.println("鼠标右键单击动作");
// }
int num = e.getClickCount();
int button = e.getButton();
switch(num) {
case 1:
if(button==MouseEvent.BUTTON1) {
System.out.println("鼠标左键单击动作");
};
if(button==MouseEvent.BUTTON3) {
System.out.println("鼠标右键单击动作");
};
break;
case 2:
if(button==MouseEvent.BUTTON1) {
System.out.println("鼠标左键双击动作");
};
break;
}
}
});
b.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("You have clicked the button!");
}
});
}
public static void main(String[] args) {
new MouseDemo();
}
}
键盘事件
package test;
import java.awt.*;
import java.awt.event.*;
public class KeyDemo {
//演示键盘事件, 加入文本框
private Frame f;
private TextField tf;
// private Button b;
KeyDemo(){
init();
}
//初始化函数
public void init() {
//设置Frame
f = new Frame("My Window");
f.setBounds(550, 250, 500, 300);
f.setLayout(new FlowLayout());
//设置TestField
tf = new TextField();
// tf = new TextField(10);
tf.setColumns(10);
//放置组件
f.add(tf);
// b = new Button("click");
// f.add(b);
myEvents();
//显示窗口
f.setVisible(true);
}
private void myEvents() {
//设置关闭窗口
f.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
//输入状态下按下Ctrl+ESC关闭窗口
tf.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
if(e.isControlDown() && e.getKeyCode()==KeyEvent.VK_ENTER) {
System.exit(0);
}
//文本框内只允许输入数字
int num = e.getKeyCode();
if(num<KeyEvent.VK_0 || num>KeyEvent.VK_9) {
//不在数字范围内时, 禁止输入到文本框中
e.consume();
}
}
});
}
public static void main(String[] args) {
new KeyDemo();
}
}
布局
Frame
package test;
import java.awt.*;
import java.awt.event.*;
public class WindowDemo {
//演示建立基本窗口
public static void myWindow() {
//窗口对象
Frame f = new Frame("My Window");
//设置窗口大小
f.setSize(500, 300);
//设置位置
f.setLocation(550, 250);
//设置布局
f.setLayout(new FlowLayout());
//添加监视器并设置关闭动作
f.addWindowListener(new WindowAdapter() {
//实现关闭操作
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
//设置窗口可见
f.setVisible(true);
}
public static void main(String[] args) {
myWindow();
}
}
Button
package test;
import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class ButtonDemo {
//窗口上添加button并指定功能
public static void myButton() {
Frame f = new Frame("My Window");
//设置窗口位置以及大小
f.setBounds(550, 250, 500, 300);
//设置布局
f.setLayout(new FlowLayout());
//添加监视器并设置关闭动作
f.addWindowListener(new WindowAdapter() {
//实现关闭操作
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
//button
Button b = new Button("click");
//设置button监视器
b.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("You have clicked the button!");
}
});
//添加button
f.add(b);
//设置窗口可见
f.setVisible(true);
}
public static void main(String[] args) {
myButton();
}
}
规范写法
package test;
import java.awt.*;
import java.awt.event.*;
public class NormalDemo {
private Frame f;
private Button b;
NormalDemo(){
init();
}
//初始化函数
public void init() {
f = new Frame("My Window");
b = new Button("click");
f.setBounds(550, 250, 500, 300);
f.setLayout(new FlowLayout());
f.add(b);
myEvents();
f.setVisible(true);
}
private void myEvents() {
f.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
b.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("You have clicked the button!");
}
});
}
public static void main(String[] args) {
new NormalDemo();
}
}
Dialog
package test;
import java.awt.*;
import java.awt.event.*;
import java.io.File;
/**
* 将指定目录下的所有文件和文件夹输出在文本区域中
* 并添加提示对话框
* @author 14251
*
*/
public class MyWindowDemo {
private Frame f;
private Button b;
private TextField tf;
private TextArea ta;
private File file;
public MyWindowDemo() {
init();
}
public void init() {
//窗口信息
f = new Frame("My Window");
f.setLayout(new FlowLayout());
f.setBounds(450, 150, 500, 500);
//按钮信息
b = new Button("查询");
//文本框信息
tf = new TextField();
tf.setColumns(33);
//文本区域信息
ta = new TextArea(25, 40);
//添加组件
f.add(tf);
f.add(b);
f.add(ta);
f.setVisible(true);
//导入事件
myEvents();
}
private void myEvents() {
f.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
b.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
showInfo();
}
});
//敲回车也能获取文件目录
tf.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
if(KeyEvent.VK_ENTER==e.getKeyCode()) {
showInfo();
}
}
});
}
private void showInfo() {
String dirPath = tf.getText();
file = new File(dirPath);
if(file.exists() && file.isDirectory()) {
ta.setText("");
String[] names = file.list();
for(String name : names) {
ta.append(name+"\r\n");
}
}else {
pathNotExistDialog();
}
}
//路径不存在的对话框
private void pathNotExistDialog() {
//对话框
Dialog d = new Dialog(f, "注意", false);
d.setBounds(520, 275, 400, 150);
d.setLayout(new FlowLayout());
//标签
Label lab = new Label(file.getAbsolutePath()+"不存在, 请重新输入!");
// lab.setText(file.getAbsolutePath()+"不存在, 请重新输入!");
//按钮
Button okB = new Button("确定");
//添加组件
d.add(lab);
d.add(okB);
d.setVisible(true);
d.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
d.setVisible(false);
}
});
okB.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
d.setVisible(false);
}
});
}
public static void main(String[] args) {
new MyWindowDemo();
}
}
MenuBar
package test;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
/**
* 演示MenuBar, Menu, MenuItem
* MenuBar-菜单栏, Menu-菜单, MenuItem-菜单项
* MenuBar可以放置Menu, Menu可以放置Menu和MenuItem
* Frame通过setMenuBar()设置MenuBar, Menu通过add()添加Menu或MenuItem
* @author 14251
*
*/
public class MenuDemo {
private Frame frame;
private TextArea textArea;
//用来记录当前对象是否有文件对象,
//若有, 则不弹出Dialog窗口
private File f;
//用于打开或保存文件
private FileDialog file_load, file_save;
private MenuBar menuBar;
private Menu file, create;
private MenuItem fileItem, dirItem, open, save, quit;
public MenuDemo(){
init();
}
public void init() {
//初始化
frame = new Frame();
textArea = new TextArea();
file_load = new FileDialog(frame, "打开文件", FileDialog.LOAD);
file_save = new FileDialog(frame, "保存文件", FileDialog.SAVE);
menuBar = new MenuBar();
file = new Menu("文件");
create = new Menu("新建");
fileItem = new MenuItem("文件");
dirItem = new MenuItem("文件夹");
open = new MenuItem("打开");
save = new MenuItem("保存");
quit = new MenuItem("退出");
//Frame上添加MenuBar以及文本区域
frame.setMenuBar(menuBar);
frame.add(textArea);
//MenuBar上添加file
menuBar.add(file);
//file上添加create, open, quit
file.add(create);
file.add(open);
file.add(save);
file.add(quit);
//create上添加子功能
create.add(fileItem);
create.add(dirItem);
//设置窗口信息
frame.setBounds(450, 150, 500, 500);
frame.setVisible(true);
//导入事件
myMenuEvents();
}
/*
* 设置功能
*/
public void myMenuEvents() {
//Frame
frame.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
//quit-退出功能
quit.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
//open-打开文件
open.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
file_load.setVisible(true);
String path = file_load.getDirectory();
String name = file_load.getFile();
if(path==null || name==null) {
return;
}
textArea.setText("");
f = new File(path, name);
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(f));
String line = null;
while((line=br.readLine())!=null) {
textArea.append(line+"\r\n");
}
} catch(IOException e1) {
e1.printStackTrace();
} finally {
if(br!=null) {
try {
br.close();
}catch(IOException e2) {
e2.printStackTrace();
}
}
}
}
});
//save-保存文件
save.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
BufferedWriter bw = null;
if(f==null) {
//文件不存在时, 显示保存对话框, 并新建文件
file_save.setVisible(true);
String path = file_save.getDirectory();
String name = file_save.getFile();
f = new File(path, name);
}
try {
bw = new BufferedWriter(new FileWriter(f));
String content = textArea.getText();
bw.write(content);
bw.flush();
} catch (IOException e1) {
e1.printStackTrace();
} finally {
if(bw!=null) {
try {
bw.close();
}catch(IOException e2) {
e2.printStackTrace();
}
}
}
}
});
}
//主函数
public static void main(String[] args) {
new MenuDemo();
}
}