这个应用程序有两个按钮。一种是单击时随机更改颜色,另一种是更改应用程序中的标签。
问题是虽然我已经编写了单独的ActionListener
类并分别用对应方法注册了它们。
每次我单击“更改标签”按钮时,颜色也会发生变化。这里发生了什么?
package my;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import javax.swing.*;
public class SimpleGui3C {
JFrame frame;
JLabel label;
public static void main(String[] args){
SimpleGui3C gui = new SimpleGui3C();
gui.go();
}
public void go(){
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton labelButton = new JButton("Change Label");
labelButton.addActionListener(new LabelListener());
JButton colorButton = new JButton("Change Circle");
colorButton.addActionListener(new ColorListener());
label = new JLabel("I'm a label");
MyDrawPanel drawPanel = new MyDrawPanel();
frame.getContentPane().add(BorderLayout.SOUTH,colorButton);
frame.getContentPane().add(BorderLayout.CENTER,drawPanel);
frame.getContentPane().add(BorderLayout.EAST, labelButton);
frame.getContentPane().add(BorderLayout.WEST, label);
frame.setSize(300,300);
frame.setVisible(true);
}
class LabelListener implements ActionListener{
public void actionPerformed(ActionEvent event1) {
ArrayList<String> labelContent = new ArrayList<String>();
labelContent.add("Ouch!");
labelContent.add("Damn!");
labelContent.add("Holy shit!");
labelContent.add("WTF?!");
labelContent.add("Stop it!");
labelContent.trimToSize();
int i = (int)(Math.random()*5);
String a = (String)labelContent.get(i);
label.setText(a);
}
}
class ColorListener implements ActionListener{
public void actionPerformed(ActionEvent event2) {
frame.repaint();
}
}
}
package my;
import java.awt.*;
import javax.swing.*;
public class MyDrawPanel extends JPanel{
/**
*
*/
private static final long serialVersionUID = 1L;
public void paintComponent(Graphics g){
Graphics2D g2d = (Graphics2D) g;
int red = (int)(Math.random()*255);
int blue = (int)(Math.random()*255);
int green = (int)(Math.random()*255);
Color startColor = new Color(red,blue,green);
red = (int)(Math.random()*255);
blue = (int)(Math.random()*255);
green = (int)(Math.random()*255);
Color endColor = new Color(red,blue,green);
int startPositionX = (int)(Math.random()*70);
int startPositionY = (int)(Math.random()*70);
int endPositionX = (int)(Math.random()*150);
int endPositionY = (int)(Math.random()*150);
GradientPaint gradient = new GradientPaint(startPositionX,startPositionY,startColor,endPositionX,endPositionY,endColor);
g2d.setPaint(gradient);
g2d.fillOval(20,60,100,100);
}
}