scrollRectToVisible doesn't move scrollpane to top

Question

Below is a shortened version of my code to illustrate the problem. I was hoping scrollRectToVisible would move the scrollbar and scrollpane back to the top but it remains at the bottom. Thanks in advance for any suggestions.

package testing;

import javax.swing.SwingUtilities;

public class Testing {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new GUItest();
            }
        });
    }
}

package testing;

import java.awt.Dimension;
import java.awt.Rectangle;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JScrollPane;

public class GUItest extends JFrame {
    private JEditorPane myEditorPane;
    private JScrollPane myScrollPane;
    public GUItest() {
        myEditorPane = new JEditorPane();
        myScrollPane = new JScrollPane(myEditorPane);
        myScrollPane.setPreferredSize(new Dimension(400, 200));
        getContentPane().add(myScrollPane);
        myEditorPane.setContentType("text/html");
        myEditorPane.setText("<html>" + "test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>" + "</html>");
        Rectangle rect = new Rectangle(1, 1, 1, 1);
        myEditorPane.scrollRectToVisible(rect);
        pack();
        setVisible(true);
    }
}

Answer 1

It works if you do the scrolling "in the next frame render cycle" after the JFrame is visible:

import javax.swing.SwingUtilities;
import java.awt.Dimension;
import java.awt.Rectangle;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JScrollPane;

public class GUItest extends JFrame  {
    private JEditorPane myEditorPane;
    private JScrollPane myScrollPane;

    public GUItest(){
        myEditorPane = new JEditorPane(); 
        myScrollPane = new JScrollPane(myEditorPane);
        myScrollPane.setPreferredSize(new Dimension(400, 100));
        getContentPane().add(myScrollPane);
        myEditorPane.setContentType("text/html");
        myEditorPane.setText("<html>" + "test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>test<br>" + "</html>");
        Rectangle rect = new Rectangle(1,1,1,1);
        pack();
        setVisible(true);

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                myEditorPane.scrollRectToVisible(rect);
            }
        });
    }    


    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            public void run(){
                new GUItest();
            }
        });
    }
}

It looks like the JFrame has to be valid/visible to issue the scroll command.

scrollRectToVisible doesn't move scrollpane to top

Question

1 answers

solution1
1 ACCPTED 2019-04-13 16:54:46

scrollRectToVisible doesn't move scrollpane to top

Question

1 answers

solution1 1 ACCPTED 2019-04-13 16:54:46

solution1
1 ACCPTED 2019-04-13 16:54:46