关于Java7 ActionListener 的问题

doy1211 2013-03-14 06:51:58

以下是一小段代码，用来改变label上圆圈的颜色，理论上应该是点击“Change Color”以后颜色才会改变，实际上如果用鼠标改变窗口大小，颜色也会变
(MyDrawPanel类的代码没有粘在这里，不用理会...)

求原因...
谢谢

import java.awt.BorderLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

public class TwoButtons {

JFrame frame;

JLabel label;

/**

* @param args

*/

public static void main(String[] args) {

TwoButtons gui = new TwoButtons();

gui.go();

}

public void go() {

this.frame = new JFrame();

this.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JButton labelButton = new JButton("Change Lable");

labelButton.addActionListener(new LabelListener());

JButton colorButton = new JButton("Change Cirle");

colorButton.addActionListener(new ColorListener());

this.label = new JLabel("I'm a label");

this.label.setSize(50, 50);

MyDrawPanel drawPanel = new MyDrawPanel();

this.frame.getContentPane().add(BorderLayout.SOUTH, colorButton);

this.frame.getContentPane().add(BorderLayout.CENTER, drawPanel);

this.frame.getContentPane().add(BorderLayout.EAST, labelButton);

this.frame.getContentPane().add(BorderLayout.WEST, this.label);

this.frame.setSize(500, 500);

this.frame.setVisible(true);

}

class LabelListener implements ActionListener {

@Override

public void actionPerformed(ActionEvent arg0) {

String[] strArray = new String[5];

strArray[0] = "label1";

strArray[1] = "label2";

strArray[2] = "label3";

strArray[3] = "label4";

strArray[4] = "label5";

int random = (int) (Math.random() * 4);

TwoButtons.this.label.setText(strArray[random]);

}

}

class ColorListener implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

TwoButtons.this.frame.repaint();

}

}

}

...全文