Java程序设计附录_实训参考答案(7)

附录 实训参考答案

import java.applet.Applet; import java.awt.*;

public class T16_2_2 extends Applet{ Panel p1,p2,p3,p4; public void init(){ p1=new Panel(); p2=new Panel(); p3=new Panel(); p4=new Panel();

}

p1.setLayout(new FlowLayout(FlowLayout.CENTER)); p2.setLayout(new FlowLayout(FlowLayout.CENTER)); p3.setLayout(new FlowLayout(FlowLayout.CENTER)); p4.setLayout(new GridLayout(1,4,10,20)); Choice ch=new Choice();

ch.addItem(\ \p1.add(new Label(\号码 \p1.add(ch);

p1.add(new Button(\申请号码\p2.add(new Label(\密码 \p2.add(new TextField(15));

p2.add(new Button(\软键盘 \p3.add(new Checkbox(\记住密码\p3.add(new Checkbox(\隐身登录\p4.add(new Button(\高级设置\p4.add(new Label(\

p4.add(new Button(\登录QQ\p4.add(new Button(\登录TM\setLayout(new GridLayout(4,1,0,20)); add(p1); add(p2); add(p3); add(p4);

289

Java语言程序设计基础 }

实训19 图形用户界面（二）

实训内容

1．ActionListener及KeyListener的使用。设计如下简易聊天室程序，在文本框中输入文字，单击“发送”按钮，或在文本框中击回车键，文本框中的文字添加到多行文本区中(你可以设置多行文本区的字体颜色，字体等，使它更像一个实际的聊天室)。

2．MouseListener、MouseMotionListener的使用。设计如下绘图小程序，选择图形类别，拖动鼠标绘制不同的图形。绘圆时，鼠标起点为圆心，鼠标移动的距离为半径。

3．WindowListener的使用。设计如下GUI，运行程序时分别执行窗口的最大化、最小化、激活、失去焦点等操作，把当前操作添加到多行文本框中。

4．AdjustmentListener的使用。设计如下调色板程序，移动三个滚动条，改变测试区的背景颜色。 参考答案

1．

import java.awt.*;

import java.awt.event.*;

public class T17_1 extends Frame implements ActionListener,KeyListener{ TextArea textArea1=new TextArea(6,30); TextField textField1=new TextField(30); Button button1=new Button(\发送\

Panel panel1=new Panel(); public T17_1(){ super(\聊天室\

panel1.setLayout(new FlowLayout()); panel1.add(textField1); panel1.add(button1);

add(textArea1,BorderLayout.CENTER); add(panel1,BorderLayout.SOUTH); textField1.addKeyListener(this); button1.addActionListener(this);

addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent e){ System.exit(0);

290

附录 实训参考答案

} 2．

} }); setSize(400,300); }

//implementation of ActionListener

public void actionPerformed(ActionEvent e){ textArea1.append(\月明风清说：\}

//implementation of KeyListener public void keyPressed(KeyEvent e){ if(e.getKeyCode()==KeyEvent.VK_ENTER){ textArea1.append(\月明风清说：\ } }

public void keyReleased(KeyEvent e){} public void keyTyped(KeyEvent e){} public static void main(String[] args){ new T17_1().setVisible(true); }

import java.applet.Applet; import java.awt.*;

import java.awt.event.*;

public class T17_2 extends Applet implements MouseListener,MouseMotionListener { int x1,y1,x2,y2; CheckboxGroup checkboxGroup1=new CheckboxGroup(); Checkbox checkbox1,checkbox2,checkbox3; public void init(){ checkbox1=new Checkbox(\画直线\ checkbox2=new Checkbox(\画圆\ checkbox3=new Checkbox(\画矩形\

add(checkbox1); add(checkbox2); add(checkbox3);

291

Java语言程序设计基础

}

}

addMouseListener(this);

addMouseMotionListener(this);

public void paint(Graphics g){ if(checkbox1.getState()==true){//draw line g.drawLine(x1,y1,x2,y2); } if(checkbox2.getState()==true){//draw Circle int r=(int)Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)); g.drawOval(x1,y1,r,r); } if(checkbox3.getState()==true){//draw Rectangle g.drawRect(x1,y1,x2,y2); } }

//implementation of MouseListener

public void mousePressed(MouseEvent e){ x1=e.getX(); y1=e.getY(); }

public void mouseClicked(MouseEvent e){} public void mouseEntered(MouseEvent e){} public void mouseExited(MouseEvent e){} public void mouseReleased(MouseEvent e){} //implementation of MouseMotionEvent public void mouseDragged(MouseEvent e){ x2=e.getX(); y2=e.getY(); repaint(); }

public void mouseMoved(MouseEvent e){}

3．

import java.awt.*;

292

附录 实训参考答案

import java.awt.event.*;

public class T17_3 extends Frame implements WindowListener{ TextArea textArea1=new TextArea(6,30); public T17_3(){ super(\窗口事件示例\ }

}

add(textArea1,BorderLayout.CENTER); addWindowListener(this); setSize(400,300);

//implementation of WindowListener

public void windowClosing(WindowEvent e){ System.exit(0); }

public void windowClosed(WindowEvent e){} public void windowOpened(WindowEvent e){ textArea1.append(\窗口被打开\\n\}

public void windowActivated(WindowEvent e){ textArea1.append(\窗口被激活\\n\ }

public void windowDeactivated(WindowEvent e){ textArea1.append(\窗口失去焦点\\n\}

public void windowIconified(WindowEvent e){ textArea1.append(\窗口最小化\\n\}

public void windowDeiconified(WindowEvent e){ textArea1.append(\窗口还原\\n\}

public static void main(String[] args){ new T17_3().setVisible(true); }

4．

import java.awt.*;

import java.awt.event.*;

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