java中创建了一个dialog，dialog中有一个按钮，点击这个按钮改变拥有者框架panel的颜色

发布网友 发布时间：2022-07-22 03:56

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热心网友 时间：2023-11-04 19:41

我看了你的程序，帮你改了一下，现在运行没问题了，你看看吧。
完整的程序如下：（改动的地方见注释）
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class SureChangeTest {
public static void main(String[] args){
EventQueue.invokeLater(new Runnable(){
public void run(){
SureChangeTestFrame frame = new SureChangeTestFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
class SureChangeTestFrame extends JFrame{
public SureChangeTestFrame(){
setTitle("sure to change the color");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
panel = new JPanel(); //这里JPanel panel=new JPanel();改成panel=new JPanel();
JButton yellowbutton = new JButton("yellow");
yellowbutton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event){
if(dialog == null){
dialog = new ColorDialog(SureChangeTestFrame.this);
dialog.setVisible(true);//这里把这一句移到if语句里
}
}
});
panel.add(yellowbutton);
add(panel);
}
public static final int DEFAULT_WIDTH = 300;
public static final int DEFAULT_HEIGHT = 200;
private ColorDialog dialog;
public static JPanel panel;//这里private JPanel panel;改成public static JPanel panel;
}
class ColorDialog extends JDialog{
public ColorDialog(JFrame owner){
super(owner,"sure?",true);
add(new JLabel("Are you sure to change the panel color?"),BorderLayout.CENTER);
JButton ok = new JButton("ok");
ok.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event){
SureChangeTestFrame.panel.setBackground(Color.YELLOW);//这里panel.setBackground(Color.YELLOW);改成SureChangeTestFrame.panel.setBackground(Color.YELLOW);
}
});
JButton cancel = new JButton("cancel");
cancel.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event){
setVisible(false);
}
});
JPanel buttonpanel = new JPanel();
buttonpanel.add(ok);
buttonpanel.add(cancel);
add(buttonpanel,BorderLayout.SOUTH);
setSize(250,150);
}
}