Java: Can't apply Gridlayout to a Jscrollpane. Get Get java.lang.ClassCastException

Question

I use a Gridlayout to place 4 elements in one Line. First I had a JPanel and everything worked fine. For the case that the number of lines get to big and I have to be able to sc

Answer 1

scrollPane.setLayout(new GridLayout(0,4)); //Line which causes the error

You can't change the layout manager of a scrollpane.

A JScrollPane has its own custom layout manager because it needs to manage the horizontal/vertical scrollbars as well as the row/column headers etc..

Instead you add a panel that uses a GridLayout:

JPanel panel = new JPanel( new GridLayout(0, 4) );
panel.add( component1 );
panel.add( component2 );
panel.add( component3 );
panel.add( component4 );
JScrollPane = new JScrollPane( panel );