Resizing issue with canvas within jscrollpane within jsplitpane

Question

I\'m creating an application using the NetBeans GUI Editor, in which I want to have a JSplitPane, the top component of which will be a Canvas withi

Answer 1

As I said in my comments, you should not mix AWT and Swing components. I think you are not using the components in the correct way. Take a look, it is a simple example of how to use a JSplitPane.

import java.awt.*; // it is necessary to use the Dimension and BorderLayout classes
import javax.swing.*;

public class Foo extends JFrame {

    public Foo() {

        setTitle( "Splits" );
        setDefaultCloseOperation( EXIT_ON_CLOSE );
        setSize( 400, 400 );

        JSplitPane split = new JSplitPane( JSplitPane.VERTICAL_SPLIT );
        split.setDividerLocation( 200 );
        add( split );

        JPanel panel1 = new JPanel();
        panel1.setLayout( new BorderLayout() );
        panel1.add( new JLabel( "top panel" ), BorderLayout.NORTH );

        JPanel myDrawPanel = new JPanel();
        myDrawPanel.setPreferredSize( new Dimension( 100, 100 ) );
        myDrawPanel.add( new JLabel( "draw panel here!" ) );
        panel1.add( new JScrollPane( myDrawPanel ), BorderLayout.CENTER );

        split.setTopComponent( panel1 );


        JPanel panel2 = new JPanel();
        panel2.add( new JLabel( "bottom panel" ) );
        split.setBottomComponent( panel2 );


        setVisible( true );

    }

    public static void main( String[] args ) {
        new Foo();
    }

}

Answer 2

Instead of setPreferredSize(), let your components calculate their own preferred size and pack() the enclosing Window to accommodate. The example below adds an instance of draw.GraphPanel to the top and a corresponding control panel to the bottom.

import draw.GraphPanel;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;

/**
 * @see https://stackoverflow.com/q/11942961/230513
 */
public class SplitGraph extends JPanel {

    public SplitGraph() {
        super(new GridLayout());
        JSplitPane split = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
        GraphPanel graphPanel = new GraphPanel();
        split.setTopComponent(new JScrollPane(graphPanel));
        split.setBottomComponent(graphPanel.getControlPanel());
        this.add(split);
    }

    private void display() {
        JFrame f = new JFrame("SplitGraph");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(this);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new SplitGraph().display();
            }
        });
    }
}

Answer 3

After reading the comment by davidbuzatto I googled about mixing AWT and Swing components and I was a little surprissed to find out that it is such a bad practice.

I found the most accurate answer to my question here

Heavyweight components have their own Z-ordering. This is the reason why Swing and AWT cannot be combined in a single container. If they are, the AWT components will be drawn on TOP of Swing components.

For example: When AWT components are used with JtabbedPane, they do not disappear when the tabs are switched.

Thanks davidbuzatto for showing me the way :-)