Question

I am struggling with java GUI – thanks for any help in advance! I have a JFrame in which I have several components: button (Jbutton) that triggers action listener, comp which is a component Im trying to replace a JScrollPane with a component in it (it doesnt matter what type of component, could be text field, table or anything).

I would like to trigger an action – delete the component, place a new one on the same place as the deleted one and repaint the window (I am using this to show different types of text fields and JTables). This is what I have:

JScrollPane sp = new JScrollPane(comp);
this.add(sp, BorderLayout.CENTER);
//this works so far - first time I display this is ok!

private void replace() {
 comp = new Component(...); //name and type of the components is not important
 sp = new JSCrollPane(comp);
 this.remove(sp); //remove old component
 add(sp, BorderLayout.CENTER);
 repaint();
 revalidate();
}

Why doesnt function replace work? It doesnt do anything (it changes the component in logic so if I access the content of comp, it is refreshed but it still shows the old one).

I wrote it kinda symbolic, cause my code is very long… Thanks for any help!
edit: forgot one line in my code..

Answer 1

It’s not necessary for you to try to remove the scroll pane as you did.

To change the component shown by the scroll pane simply make this call:

sp.setViewportView(new Component(...));

after that call, the old component is removed from view and replaced by the new component.

So your code should look somewhat like this:

JScrollPane sp = new JScrollPane(comp);
this.add(sp, BorderLayout.CENTER);

private void replace() {
    comp = new Component(...); //name and type of the components is not important
    sp.setViewportView(comp);
}