在按钮上单击加载JList

Question

I want to show a JList whenever user clicks on a button. Here is my code on button click event:

public void loadListBtnActionPerformed(java.awt.event.ActionEvent evt){
       JList myJList = new javax.swing.JList();
        myJList.setVisibleRowCount(10);
        jPanel7.add(myJList);
        jPanel7.revalidate();
        jPanel7.repaint();
}

The problem is it is not showing any list on button click. How to add the list on button click?

Answer 1

Assuming that you're using the default FlowLayout for jPanel7 (and GroupLayout for the JFrame layout), the JList will not appear as it doesn't contain any elements so its preferred size will be 0x0 .

To allow the JList content to be scrollable you should place it in a JScrollPane . This will make it appear even when it is initially empty:

jPanel7.add(new JScrollPane(myJList));