在java中动态添加复选框

Question

I wonder how to add checkboxes and name dynamically .

The number of checkboxes is follow the number of row in MySQL and the name is retrieved from MySQL . Assume I have three data in MySQL , so I would get output as image above.

This is my code for class A

checkAPI api= new checkAPI();

try 
{
    num = api.displayCheckBoxAndLabel(); //  get 3
    List<String> allName= api.displayName(); // [John,Tony,Kik]
} 
catch (Exception e1) 
{
    // TODO Auto-generated catch block
    e1.printStackTrace();
                            }    
    deleteAdmin delete = new deleteAdmin(num,allName);
    delete.setVisible(true);
    setVisible(false);
    dispose();
} 

Then pass the two parameters to class deleteAdmin

public class deleteAdmin  extends JFrame {

    private JPanel contentPane;
    private JTextField userText;
    private JTextField txtpassword;
    JFrame f= new JFrame(" Add Admin");

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    button frame = new button();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public deleteAdmin(int num, List<String> names)
    {
        super("Delete Admin");
        setBounds(100, 200, 340, 229);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JPanel panel = new JPanel();
        panel.setBounds(35, 19, 242, 146);
        contentPane.add(panel);
        panel.setLayout(null);

        JCheckBox[] checkBoxList = new JCheckBox[num];

        for(int i = 0; i < num; i++) {
            checkBoxList[i] = new JCheckBox("CheckBox" + i);
            contentPane.add(checkBoxList[i]);
        }
    }
}

However, I get this kind of output. No checkboxes shown :(

Answer 1

From a quick look there are at least two possible oddities in your code.

1. If you do not use a layout manager for your panels, you have to size and place your components explicitly.

2. Swing components must be created and manipulated exclusively on the event dispatch thread. So if your code

    deleteAdmin delete= new deleteAdmin(num,allName); delete.setVisible(true); setVisible(false); dispose(); 

   Runs in the EDT because it is inside some button handler or like that it is ok, otherwise you need to use invokeLater() to do that stuff.