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JScrollpane and Textarea
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import javax.swing.ScrollPaneConstants;
import javax.swing.SwingUtilities;
public class Main {
static final Box inner = Box.createVerticalBox();
// if the jtextarea should contain text
private static boolean textEnabled = true;
public static void main(final String[] args) {
final JFrame frame = new JFrame();
final JPanel insideScroll = insideScroll();
final JScrollPane scrollpane = new JScrollPane(insideScroll);
scrollpane.setAutoscrolls(false);
scrollpane
.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
final JPanel rightPanel = new JPanel();
rightPanel.setPreferredSize(new Dimension(300, 300));
rightPanel.addMouseMotionListener(new MouseMotionAdapter() {
@Override
public void mouseDragged(final MouseEvent e) {
super.mouseDragged(e);
final int pos = scrollpane.getVerticalScrollBar().getValue();
update();
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
System.out.println(String.format("[Out] %s", pos));
}
});
}
});
// Add labels describing the problem
rightPanel.setLayout(new BoxLayout(rightPanel, BoxLayout.PAGE_AXIS));
final JButton toggleButton = new JButton("Toggle text");
rightPanel.add(toggleButton);
rightPanel
.add(new JLabel(
"<html>If the text is disabled, you can press/drag<br> your mouse on on right side of the<br> window and the scrollbar will<br> stay in its position."));
rightPanel
.add(new JLabel(
"<html>If the text is enabled, the scrollbar<br> will jump around when dragging<br> on the right side."));
// enable/disable the text when the button is clicked.
toggleButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(final ActionEvent e) {
textEnabled = !textEnabled;
update();
}
});
final JSplitPane split = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
scrollpane, rightPanel);
frame.add(split);
// initialize the scrollpane content
update();
frame.pack();
frame.setVisible(true);
frame.setLocationRelativeTo(null);
}
// initializes the components inside the scrollpane
private static JPanel insideScroll() {
final JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.add(inner, BorderLayout.NORTH);
return panel;
}
// replaces all components inside the scrollpane
private static void update() {
inner.removeAll();
for (int i = 0; i < 30; i++) {
inner.add(buildRow(i));
}
inner.revalidate();
}
// build a single component to be inserted into the scrollpane
private static JPanel buildRow(final int i) {
final JPanel row = new JPanel();
final Color bg = i % 2 == 0 ? Color.DARK_GRAY : Color.LIGHT_GRAY;
row.setBackground(bg);
row.setPreferredSize(new Dimension(300, 80));
row.setLayout(new BorderLayout());
row.add(textarea(bg), BorderLayout.CENTER);
return row;
}
// build the textarea to be inserted into the cells in the scroll pane
private static Component textarea(final Color bg) {
final JTextArea textarea = new JTextArea();
textarea.setEnabled(false);
textarea.setLineWrap(true);
textarea.setBackground(bg);
textarea.setDisabledTextColor(Color.black);
textarea.setEditable(false);
if (textEnabled) {
textarea.setText("Lorem ipsum dolor si amet. Lorem ipsum dolor si amet. Lorem ipsum dolor si amet");
}
return textarea;
}
}
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