AWT/Swing编程题

priestmoon 2009-05-24 08:46:15

题目：添加三个按钮Red, Yellow, Blue，使窗口中央的"Hello world"显示相应的颜色。



import java.awt.*;

import java.awt.event.*;

import java.awt.geom.*;

import javax.swing.*;



public class HelloWorld {

  public static void main(String[] args) {

    HelloWorldFrame frame = new HelloWorldFrame();

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    frame.setVisible(true);

  }

}



class HelloWorldFrame extends JFrame {

  public JFrame() {

    add(new HelloWorldPanel());

    setSize(WIDTH, HEIGHT);

  }



  private static final int WIDTH = 400;

  private static final int HEIGHT = 400;

}



class HelloWorldPanel extends JPanel {

  //*******************************  

  

  //???????????????????????????????  



  //*******************************

  private static final int leftX = 100;

  private static final int topY = 200;

}

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raymondguo008 2009-05-26

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import java.awt.*;

import java.awt.event.*;

import javax.swing.*;



public class ButtonTest {

	public static void main(String[] args) {

		ButtonFrame frame = new ButtonFrame();

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}

}



class ButtonFrame extends JFrame {

	public ButtonFrame() {

		setTitle("ButtonTest");

		setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

		

		ButtonPanel panel = new ButtonPanel();

		add(panel);

	}

	

	public static final int DEFAULT_WIDTH = 300;

	public static final int DEFAULT_HEIGHT = 200;

}



class ButtonPanel extends JPanel {

	public ButtonPanel() {

		JButton yellowButton = new JButton("Yellow");

		JButton blueButton = new JButton("Blue");

		JButton redButton = new JButton("Red");

		

		add(yellowButton);

		add(blueButton);

		add(redButton);

		

		ColorAction yellowAction = new ColorAction(Color.YELLOW);

		ColorAction blueAction = new ColorAction(Color.BLUE);

		ColorAction redAction = new ColorAction(Color.RED);		

		

		yellowButton.addActionListener(yellowAction);

		blueButton.addActionListener(blueAction);

		redButton.addActionListener(redAction);

	}

	

	private class ColorAction implements ActionListener {

		

		private Color backgroundColor;

		

		public ColorAction(Color c) {

			backgroundColor = c;

		}

		

		public void actionPerformed(ActionEvent event) {

			setBackground(backgroundColor);

		}		

	}

}

raymondguo008 2009-05-26

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import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class ButtonTest {
public static void main(String[] args) {
ButtonFrame frame = new ButtonFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}

class ButtonFrame extends JFrame {
public ButtonFrame() {
setTitle("ButtonTest");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

ButtonPanel panel = new ButtonPanel();
add(panel);
}

public static final int DEFAULT_WIDTH = 300;
public static final int DEFAULT_HEIGHT = 200;
}

class ButtonPanel extends JPanel {
public ButtonPanel() {
JButton yellowButton = new JButton("Yellow");
JButton blueButton = new JButton("Blue");
JButton redButton = new JButton("Red");

add(yellowButton);
add(blueButton);
add(redButton);

ColorAction yellowAction = new ColorAction(Color.YELLOW);
ColorAction blueAction = new ColorAction(Color.BLUE);
ColorAction redAction = new ColorAction(Color.RED);

yellowButton.addActionListener(yellowAction);
blueButton.addActionListener(blueAction);
redButton.addActionListener(redAction);
}

private class ColorAction implements ActionListener {

private Color backgroundColor;

public ColorAction(Color c) {
backgroundColor = c;
}

public void actionPerformed(ActionEvent event) {
setBackground(backgroundColor);
}
}
}

priestmoon 2009-05-26

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runshine && gentalguo
Good!

gentalguo 2009-05-26

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从你所定义的变量，我猜测也许你是这样的意图。
简单写了一点。恩，你是说panel里面不要标签，直接写字吧？
你看一下代码，如果还不是你要的，那么描述的再详细一些。

import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class HelloWorld {
public static void main(String[] args) {
HelloWorldFrame frame = new HelloWorldFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}

class HelloWorldFrame extends JFrame {
public HelloWorldFrame() {
add(new HelloWorldPanel());
setSize(WIDTH, HEIGHT);
}

private static final int WIDTH = 400;
private static final int HEIGHT = 400;
}

class HelloWorldPanel extends JPanel {
private Color color = Color.WHITE;

public HelloWorldPanel() {
setLayout(new FlowLayout());
JButton redButton = new JButton("Red");
JButton yellowButton = new JButton("Yellow");
JButton blueButton = new JButton("Blue");
add(redButton);
add(yellowButton);
add(blueButton);

redButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
color = Color.red;
repaint();
}
});
yellowButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
color = Color.YELLOW;
repaint();
}
});
blueButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
color = Color.BLUE;
repaint();
}
});
}

@Override
public void paint(Graphics g) {
super.paint(g);
g.setColor(color);
g.drawString("HelloWorld", leftX, topY);
}

private static final int leftX = 100;
private static final int topY = 200;
}

runshine 2009-05-25

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import java.awt.*;

import java.awt.event.*;

import java.awt.geom.*;

import javax.swing.*;



public class HelloWorld {

  public static void main(String[] args) {

    HelloWorldFrame frame = new HelloWorldFrame();

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    frame.setVisible(true);

  }

}



class HelloWorldFrame extends JFrame {

  public HelloWorldFrame() {

    add(new HelloWorldPanel());

    setSize(WIDTH, HEIGHT);

  }



  private static final int WIDTH = 400;

  private static final int HEIGHT = 400;

}



class HelloWorldPanel extends JPanel implements ActionListener

{

  JPanel p=new JPanel();

  JButton r,b,y;

  JLabel l;

  public HelloWorldPanel()

  {

  l=new JLabel("Hello world!");

  r=new JButton("Red");

  y=new JButton("Yellow");

  b=new JButton("Blue");

  r.addActionListener(this);

  b.addActionListener(this);

  y.addActionListener(this);

  

  p.add(r);

   p.add(y);

  p.add(b);

  

  add(l,BorderLayout.CENTER);

  add(p,BorderLayout.SOUTH);

  setSize(leftX,topY);

  this.setVisible(true);

  }

  private static final int leftX = 100;

  private static final int topY = 200;



  public void actionPerformed(java.awt.event.ActionEvent e)

  {

  	if(e.getSource()==r){

           l.setForeground(Color.red);

         }

         if(e.getSource()==b){

           l.setForeground(Color.blue);

         }

         if(e.getSource()==y){

           l.setForeground(Color.yellow);

         }

  }

}

priestmoon 2009-05-25

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楼上的代码是让显示"Hello World"的Label所在的矩形范围的背景颜色变色。
如果要让"Hello World"本身的字体颜色改变，应该怎么写？

goodmrning 2009-05-24

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class HelloWorldPanel extends JPanel impletments ActionListener{

  JPanel p=new JPanel();

  JButton r,b,y;

  JLabel l;

  l=new JLable("Hello world!");

  r=new JButton("Red");

  y=new JButton("Yellow");

  b=new JButton("Blue");

  p.add(r);

   p.add(y);

  p.add(b);

  r.addActionListener(this);

  b.addActionListener(this);

  y.addActionListener(this);

  getContentPane.add(l,BorderLayout.CENTER);

  getContentPane.add(p,BorderLayout.SOUTH);

  setSize(leftX,topY);

  setVisiable(true);

  

  private static final int leftX = 100;

  private static final int topY = 200;

  public void actionperformed(ActionEvent e){

         if(e.getSource==r){

           l.setbackground(Color.red);

         }

         if(e.getSource==b){

           l.setbackground(Color.blue);

         }

         if(e.getSource==y){

           l.setbackground(Color.yellow);

         }

}

priestmoon 2009-05-24

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怎么没人做？
这道题很难吗？
架子都搭好了，只要填几行关键代码就行了啊。

priestmoon 2009-05-24

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代码中有错误，修改如下：



import java.awt.*;

import java.awt.event.*;

import java.awt.geom.*;

import javax.swing.*;



public class HelloWorld {

  public static void main(String[] args) {

    HelloWorldFrame frame = new HelloWorldFrame();

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    frame.setVisible(true);

  }

}



class HelloWorldFrame extends JFrame {

  public HelloWorldFrame() {

    add(new HelloWorldPanel());

    setSize(WIDTH, HEIGHT);

  }



  private static final int WIDTH = 400;

  private static final int HEIGHT = 400;

}



class HelloWorldPanel extends JPanel {

  //*******************************  

  

  //???????????????????????????????  



  //*******************************

  private static final int leftX = 100;

  private static final int topY = 200;

}