Java – how do I change the contents of the JScrollPane significantly each time I call the actionlistener?
Every time I call the action listener, I want the JScrollPane to change its list to a completely different list I'm not quite sure how to do this I've tried to change JList, redraw scrollpane and revalidate it, but it didn't bring the expected effect I wrote an editable Mini program to explain my problem here:
import javax.swing.*;
import javax.swing.border.TitledBorder;
import java.awt.*;
import java.awt.event.*;
import java.sql.sqlException;
@SuppressWarnings("serial")
public class TestFrame extends JFrame {
public final Dimension SCROLL_PANE_DIMENSION = new Dimension(200,100);
private JCombo@R_781_2419@<String> comboNames;
private JPanel panel = new JPanel();
private JList<String> availableList;
private JScrollPane theScrollPane;
private boolean string1Used = true;
String[] strings = { "Aaardvark","Adam","Alms" };
String[] strings2 = { "Bad","Bugs","Bunny" };
public static void main(String[] args){
try {
TestFrame frame = new TestFrame();
frame.setVisible(true);
} catch (sqlException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public TestFrame() throws sqlException {
String[] comboStrings = { "Doesn't","matter","here" };
this.setSize(300,200);
availableList = new JList<String>(strings);
theScrollPane = new JScrollPane(availableList);
theScrollPane = new JScrollPane(availableList);
theScrollPane.setPreferredSize(SCROLL_PANE_DIMENSION);
theScrollPane.setSize(SCROLL_PANE_DIMENSION);
theScrollPane.setBorder(BorderFactory.createTitledBorder(
BorderFactory.createEtchedBorder(),"Sub Conditions",TitledBorder.CENTER,0));
availableList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
availableList.setSelectedIndex(0);
availableList.setVisibleRowCount(5);
availableList.setSize(SCROLL_PANE_DIMENSION);
comboNames = new JCombo@R_781_2419@<String>(comboStrings);
comboNames.addActionListener(new ConditionComboListener());
panel = new JPanel();
this.add(panel);
panel.add(comboNames);
panel.add(theScrollPane);
}
private class ConditionComboListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent arg0) {
refreshSubConditionList();
}
private void refreshSubConditionList() {
if (string1Used) {
System.out.println("Switching to Strings2");
availableList = new JList<String>(strings2);
string1Used = false;
} else{
System.out.println("Switching to Strings");
availableList = new JList<String>(strings);
string1Used = true;
}
theScrollPane = new JScrollPane(availableList);
theScrollPane.revalidate();
theScrollPane.repaint();
}
}
}
In this example, whenever I change JCombo@R_781_2419 @I want the list in JScrollPane to switch between arrays strings1 and strings2 I also hope this change is visible because I changed the content of the combo box, not later As you can see from the compiled code, it doesn't work that well What on earth did I do wrong? Why don't I want it to change the list?
Solution
Creating a new scroll pane does not add the scroll pane to the panel
In any case, there is no need to continue creating a new scroll pane Just change the components displayed in the scroll Pane:
//theScrollPane = new JScrollPane(availableList); //theScrollPane.revalidate(); //theScrollPane.repaint(); theScrollPane.setViewportView(availableList);
