复选框不显示 [英] Checkboxes not showing up
本文介绍了复选框不显示的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我希望另一套眼睛可以帮助我找到我的代码错误。我可以编译和运行程序,但我得到的是一个白色的屏幕。它应该显示复选框,并更改背景,无论选择哪种颜色。欢迎任何帮助!
I am hoping another set of eyes can help me find where my code is wrong. I can compile and run the program, but all I get is a white screen. It's supposed to show the checkboxes and change the background to whichever color is chosen. Any help is appreciated!
import javax.swing.JOptionPane;
import java.awt.*;
import java.awt.event.*;
public class Chapter5Debug extends Frame implements ItemListener
{
static Chapter5Debug f = new Chapter5Debug();
CheckboxGroup options = new CheckboxGroup();
Checkbox blue = new Checkbox("Blue",false,options);
Checkbox red = new Checkbox("Red",false,options);
Checkbox yellow = new Checkbox("Yellow",false,options);
Checkbox pink = new Checkbox("Pink",false,options);
Checkbox gray = new Checkbox("Gray",false,options);
public void Chapter5Debug()
{
this.setLayout(new FlowLayout());
add(blue);
add(red);
add(yellow);
add(pink);
add(gray);
blue.addItemListener(this);
red.addItemListener(this);
yellow.addItemListener(this);
pink.addItemListener(this);
gray.addItemListener(this);
//overriding windowClosing() allows user to click Close button
addWindowListener(
new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
}
);
} //end of constructor method
public static void main(String[] args)
{
//ColorButtons f = new ColorButtons();
f.setBounds(200,200,500,100);
f.setTitle("What's My Color?");
f.setVisible(true);
} //end of main
public void actionPerformed(ActionEvent e)
{
if (blue.getState()) f.setBackground(Color.blue);
else if (red.getState()) f.setBackground(Color.red);
else if (yellow.getState()) f.setBackground(Color.yellow);
else if (pink.getState()) f.setBackground(Color.pink);
else if (gray.getState()) f.setBackground(Color.gray);
} //end of actionPerformed method
public void itemStateChanged(ItemEvent e)
{
}
} //end of class
推荐答案
这不是一个构造函数:
public void Chapter5Debug()
{
这是一个 void
方法。你想要一个构造函数?删除 void
关键字。
it's a void
method. You want a constructor? Remove the void
keyword.
>
In this line
static Chapter5Debug f = new Chapter5Debug();
您正在调用默认构造函数, void
方法你从来没有调用过。
you are calling the default constructor, the void
method you have is never called.
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