仅当鼠标悬停在组件上时才会出现组件

如何解决仅当鼠标悬停在组件上时才会出现组件

我使用 Swing 框架创建了一个 JFrame，在其中添加了一个 JButton，它将显示在框架的 JPanel 上创建的表单。

我在按钮上添加了动作监听器，它按照我的预期显示面板；

但是无法看到单选按钮和复选框等组件的框。

只有当我将鼠标悬停在它们上面时它们才会出现。

查看单选按钮和复选框中的另一个选项：

代码如下：

package codes;

import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;

public class JFrameBackground extends JFrame implements ActionListener
{

    
    private static final long serialVersionUID = 1L;
    
    
    JLabel l1,l2,l3,l4;
    JTextField t1;
    JButton b1;
    JRadioButton r1;
    JComboBox com1;
    JCheckBox chk1;
    
    JPanel p2;
    JButton b;
    
    

    public JFrameBackground() 
    {
        
        p2=new JPanel();
        p2.setLayout(null);
        p2.setBounds(250,400,400);
        add(p2);
        
        
        l1 = new JLabel("Name:");
        l1.setBounds(100,10,70,30);
        p2.add(l1);
        
        t1 = new JTextField();
        t1.setBounds(100,50,30);
        p2.add(t1);
        
        l2 = new JLabel("Gender:");
        l2.setBounds(100,130,30);
        p2.add(l2);
        
        r1 = new JRadioButton("Male");
        r1.setBounds(100,150,30);
        p2.add(r1);
        
        r1 = new JRadioButton("Female");
        r1.setBounds(150,30);
        p2.add(r1);
        
        l3 = new JLabel("Course:");
        l3.setBounds(100,180,30);
        p2.add(l3);
        
        chk1= new JCheckBox("Bca");
        chk1.setBounds(100,200,30);
        p2.add(chk1);
        
        chk1= new JCheckBox("BBA");
        chk1.setBounds(150,30);
        p2.add(chk1);
        
        chk1= new JCheckBox("BCOM");
        chk1.setBounds(200,30);
        p2.add(chk1);
        
        l4 = new JLabel("Country:");
        l4.setBounds(100,220,30);
        p2.add(l4);
        
        String name[] = {"India","USA","UK","Rus"};
        
        com1=new JComboBox(name);
        com1.setBounds(100,250,30);
        p2.add(com1);
        
        b1= new JButton("Submit");
        b1.setBounds(140,300,90,30);
        p2.add(b1);
        
        
        
        
        b =new JButton("Show form");
        b.setBounds(0,4,190,40);
        b.setFocusPainted(false);
        b.setBorderPainted(false);
        b.addActionListener(this);
        add(b);
        
        b.addMouseListener(new MouseAdapter() 
        {
            public void mouseClicked(MouseEvent me)
            {
                
                p2.setVisible(true);
                
                
            }
        });
        
        
        
        Container c=getContentPane();
        c.setBackground(Color.gray);
        setBounds(170,100,1250,500);
        
        setLayout(null);
        setVisible(true);
    }


    public static void main(String[] args) 
    {
        
        new JFrameBackground();
        

    }

    public void actionPerformed(ActionEvent arg0) 
    {
        
        
    }

}

解决方法

左侧的组件太大，因此与复选框重叠。这就是为什么它们没有正确显示的原因。所以像这样移动正确的组件：

 r1.setBounds(170,150,70,30);
 chk1.setBounds(170,200,30);              
 chk1.setBounds(240,30);

它会起作用。

,

这似乎效果更好。

• 我修正了单选按钮和复选框的位置。

• 我对复选框和单选按钮对象（r1、r2、chk1、chk2、chk3）使用了不同的引用

• 我为单选按钮添加了一个按钮组。

   import java.awt.Color;
   import java.awt.Container;
   import java.awt.event.ActionEvent;
   import java.awt.event.ActionListener;
   import java.awt.event.MouseAdapter;
   import java.awt.event.MouseEvent;
  
   import javax.swing.JButton;
   import javax.swing.JCheckBox;
   import javax.swing.JComboBox;
   import javax.swing.JFrame;
   import javax.swing.JLabel;
   import javax.swing.JPanel;
   import javax.swing.JRadioButton;
   import javax.swing.JTextField;
  
   import javax.swing.ButtonGroup;
  
   public class JFrameBackground extends JFrame implements ActionListener
   {
  
  
       private static final long serialVersionUID = 1L;
  
  
       JLabel l1,l2,l3,l4;
       JTextField t1;
       JButton b1;
       JRadioButton r1,r2;
       JComboBox com1;
       JCheckBox chk1,chk2,chk3;
  
       JPanel p2;
       JButton b;
  
  
  
       public JFrameBackground() 
       {
  
           p2=new JPanel();
           p2.setLayout(null);
           p2.setBounds(250,400,400);
           add(p2);
  
  
           l1 = new JLabel("Name:");
           l1.setBounds(100,10,30);
           p2.add(l1);
  
           t1 = new JTextField();
           t1.setBounds(100,50,30);
           p2.add(t1);
  
           l2 = new JLabel("Gender:");
           l2.setBounds(100,130,30);
           p2.add(l2);
  
           r1 = new JRadioButton("Male");
           r1.setBounds(100,30);
           p2.add(r1);
  
           r2 = new JRadioButton("Female");
           r2.setBounds(180,30);
           p2.add(r2);
  
           ButtonGroup bg=new ButtonGroup();    
           bg.add(r1);
           bg.add(r2); 
  
           l3 = new JLabel("Course:");
           l3.setBounds(100,180,30);
           p2.add(l3);
  
           chk1= new JCheckBox("Bca");
           chk1.setBounds(100,30);
           p2.add(chk1);
  
           chk2= new JCheckBox("BBA");
           chk2.setBounds(180,30);
           p2.add(chk2);
  
           chk3= new JCheckBox("BCOM");
           chk3.setBounds(260,30);
           p2.add(chk3);
  
           l4 = new JLabel("Country:");
           l4.setBounds(100,220,30);
           p2.add(l4);
  
           String name[] = {"India","USA","UK","Rus"};
  
           com1=new JComboBox(name);
           com1.setBounds(100,250,30);
           p2.add(com1);
  
           b1= new JButton("Submit");
           b1.setBounds(140,300,90,30);
           p2.add(b1);
  
  
  
  
           b =new JButton("Show form");
           b.setBounds(0,4,190,40);
           b.setFocusPainted(false);
           b.setBorderPainted(false);
           b.addActionListener(this);
           getContentPane().add(b);
  
           b.addMouseListener(new MouseAdapter() 
           {
               public void mouseClicked(MouseEvent me)
               {
  
                   p2.setVisible(true);
  
  
               }
           });
  
  
  
           Container c=getContentPane();
           c.setBackground(Color.gray);
           setBounds(170,100,1250,500);
  
           setLayout(null);
           setVisible(true);
       }
  
  
       public static void main(String[] args) 
       {
  
           new JFrameBackground();
  
  
       }
  
       public void actionPerformed(ActionEvent arg0) 
       {
  
  
       }
  
   }