Java2实用教程（第三版）课后答案 - 耿祥义主编

setBackground(Color.cyan); }

public void setX(int x) {

this.x=x; }

public void setY(int y) {

this.y=y; }

public void setW(int w) {

this.w=w; }

public void setH(int h) {

this.h=h; }

public void paint(Graphics g) {

g.drawRect(x,y,w,h); } }

class WindowCanvas extends Frame implements ActionListener {

Mycanvas canvas;

TextField text1,text2,text3,text4; Button button; WindowCanvas() {

canvas=new Mycanvas(); text1=new TextField(4); text2=new TextField(4); text3=new TextField(5); text4=new TextField(5);

Panel pNorth=new Panel(),pSouth=new Panel(); button=new Button(\确定\

button.addActionListener(this);

pNorth.add(new Label(\矩形的宽: \pNorth.add(text3);

pNorth.add(new Label(\矩形的高: \pNorth.add(text4);

pSouth.add(new Label(\左上角位置坐标:\

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pSouth.add(text1); pSouth.add(text2); pSouth.add(button);

addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

System.exit(0); } } );

add(canvas,BorderLayout.CENTER); add(pNorth,BorderLayout.NORTH); add(pSouth,BorderLayout.SOUTH); setBounds(100,100,500,500); setVisible(true); validate(); }

public void actionPerformed(ActionEvent e) {

int x,y,w,h; try {

x=Integer.parseInt(text1.getText()); y=Integer.parseInt(text2.getText());

w=Integer.parseInt(text3.getText()); h=Integer.parseInt(text4.getText()); canvas.setX(x); canvas.setY(y); canvas.setW(w); canvas.setH(h); canvas.repaint(); }

catch(NumberFormatException ee) {

x=0;y=0;w=0;h=0; } } }

public class Test {

public static void main(String args[]) {

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new WindowCanvas(); } }

10.编写应用程序，有一个窗口对象，该窗口取它的默认布局: BorderLayout布局,北面添加一个List组件，该组件有四个商品名称的选项。中心添加一个文本区，当选择List组件中的某个选项后，文本区显示对该商品的价格和产地:当双击List组件中的某个选项后，文本区显示该商品的详细广告。 答: import java.awt.*; import java.awt.event.*;

class WindowGoods extends Frame implements ActionListener,ItemListener {

String s[]={\产地:北京\产地:上海\产地:沈阳\产地:广东\String p[]={\价格:3200\价格:158\价格:13.2\价格:320/打\String a[]={\本商品****\本商品*****\本商品******\本商品*******\List list;

TextArea text; WindowGoods() {

list=new List(3,false); text=new TextArea(6,20); text.setEditable(false); list.add(\商品1\list.add(\商品2\list.add(\商品3\list.add(\商品4\

add(list,BorderLayout.NORTH); add(text,BorderLayout.CENTER);

list.addItemListener(this); list.addActionListener(this);

addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

System.exit(0); } } );

setBounds(100,100,300,300); setVisible(true); validate(); }

public void itemStateChanged(ItemEvent e)

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{

if(e.getItemSelectable()==list) {

int m=list.getSelectedIndex(); text.setText(p[m]+'\\n'+s[m]); } }

public void actionPerformed(ActionEvent e) {

int n=list.getSelectedIndex(); text.setText(a[n]); } }

public class Test {

public static void main(String args[]) {

new WindowGoods(); } }

11.编写程序，观察各种组件设置背景色和前景色的情况。 答: import java.awt.*; import java.awt.event.*;

class WindowColor extends Frame implements ActionListener {

Button button; //按钮

TextField textfield; //文本框 TextArea textarea; //文本区 Mypanel panel; //面板

Checkbox box; //选择框 Choice choice; //下拉列表 List list; //滚动列表 Label label; //标签 Mycanvas can; //画布

Button buttonBackColor,buttonForeColor; WindowColor() {

button=new Button(\我是按钮\

textfield=new TextField(\我是文本框\textarea=new TextArea(6,15); textarea.setText(\我是文本区\textfield.setEditable(false); textarea.setEditable(false);

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