摆动：动态更改组件的可见性

Question

When I set the visibility of components (mainly JPanels that have other child components) to false or back to true later, do I have to call .revalidate() and .repaint() on the parent container explicitly or do the LayoutManagers handle this automatically?

When I tried this with a component in BorderLayout-North position for example, everything looked fine without calling revalidate. Just not sure if it will work on all platforms and with all LayoutManagers.

Answer 1

when u set the visibility of components like JPanels. JVM automatically call revalidate() and repaint() method when u set the visibility to true. u does not need to call the all these method. and it will work for all layout

Answer 2

The following code may solve your problem

      p2_wrkrreg=new JPanel();
      p2_wrkrreg.setBounds(201,0,830,720);
     // p2_wrkrreg.setLayout(null);
      //p2_wrkrreg.setBackground(Color.white);
      p2_wrkrreg.setVisible(false);

In this code,

The JPanel declared and make it invisible, it will be visible on a button click

@Override
public void actionPerformed(ActionEvent e) {       

if(e.getSource()==btn_wrkrreg)
    {
        p2_wrkrreg.setVisible(true);
    }

here btn_wrkrreg is a JButton