Java display components after intervals [closed] - swing

Question

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Closed 10 years ago.
I have a list of JComponents each having a visibility time. I have to pick each component from the List, use a swing timer, display it for the specifed visibility time after which remove the displayed component from the panel, take the next component from the list and display and so on. At a particular time I should display only one component. Please help
testList.add(new JLabel());
testList.add(new JButton());
java.util.Timer timer;
TimerTask task;
for (Iterator<> it = testList.iterator(); it.hasNext(); ) {
final JComponent comp= it.next();
comp.setSize(new Dimension(200, 200));
for(int index=0; index==getComponents().length;index++) {
if(getComponents().length==0)
add(not.getComponent(), BorderLayout.CENTER);
}
timer= new java.util.Timer();
task= new TimerTask() {
public void run() {
validate();
try {
remove(comp);
} catch (Exception e) {
e.printStackTrace();
}
validate();
repaint();
}
};
timer.schedule( task ,30*1000);
it.remove();
}

Answer 1

Try your hands on this code, will this do to satisfy your needs :-)
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import javax.swing.event.*;
public class ListAndTimer
{
private JButton button;
private JToggleButton toggleButton;
private JLabel label;
private JCheckBox cbox;
private JRadioButton rButton;
private Object[] data;
private JList myList;
private List<JComponent> components;
private JComponent lastComponent;
private JPanel contentPane;
private Timer timer;
public ListAndTimer()
{
contentPane = new JPanel();
button = new JButton("BUTTON");
button.setName("2");
toggleButton = new JToggleButton("TOGGLE BUTTON");
toggleButton.setName("3");
label = new JLabel("LABEL");
label.setName("4");
cbox = new JCheckBox("CHECKBOX", false);
cbox.setName("2");
rButton = new JRadioButton("RADIOBUTTON", false);
rButton.setName("3");
components = new ArrayList<JComponent>();
components.add(button);
components.add(toggleButton);
components.add(label);
components.add(cbox);
components.add(rButton);
data = new Object[]{
"Button", "Toggle Button", "Label",
"CheckBox", "RadioButton"
};
myList = new JList(data);
myList.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
myList.addListSelectionListener(new ListSelectionListener()
{
public void valueChanged(ListSelectionEvent lse)
{
int index = myList.getSelectedIndex();
int time = 0;
System.out.println("Index : " + index);
lastComponent = components.get(index);
contentPane.add(lastComponent);
time = Integer.parseInt(lastComponent.getName());
contentPane.revalidate();
contentPane.repaint();
timer = new Timer(time * 1000, timerAction);
timer.setRepeats(false);
timer.start();
}
});
myList.setVisibleRowCount(5);
myList.setLayoutOrientation(JList.VERTICAL_WRAP);
}
private ActionListener timerAction = new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
contentPane.remove(lastComponent);
contentPane.revalidate();
contentPane.repaint();
}
};
private void createAndDisplayGUI()
{
JFrame frame = new JFrame("List And Timer");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.getContentPane().add(contentPane, BorderLayout.CENTER);
frame.getContentPane().add(myList, BorderLayout.LINE_END);
frame.setSize(300, 300);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new ListAndTimer().createAndDisplayGUI();
}
});
}
}

Answer 2

You could do it for example like this:
private static int current = 0;
public static void main ( String[] args )
{
final List<Component> components = new ArrayList<Component> ();
components.add ( new JButton ( "Button" ) );
components.add ( new JToggleButton ( "Toggle" ) );
components.add ( new JLabel ( "Label" ) );
components.add ( new JCheckBox ( "Check" ) );
components.add ( new JRadioButton ( "Radio" ) );
final JPanel panel = new JPanel ();
panel.setBorder ( BorderFactory.createEmptyBorder ( 50, 50, 50, 50 ) );
panel.add ( components.get ( current ) );
JFrame frame = new JFrame ();
frame.add ( panel );
frame.pack ();
frame.setLocationRelativeTo ( null );
frame.setVisible ( true );
new Timer ( 2000, new ActionListener ()
{
public void actionPerformed ( ActionEvent e )
{
current = current < components.size () - 1 ? current + 1 : 0;
panel.removeAll ();
panel.add ( components.get ( current ) );
panel.revalidate ();
panel.repaint ();
}
} ).start ();
}
There are a few important things here:
1. Remove old component from the panel (i just remove all existing to simplify the code)
2. Add new one on the same location in layout
3. Revalidate container (JPanel) so it updates its childs bounds
4. Repaint container so you will see the changes properly
Also this (i mean the part of code, that changes JPanel content) should be done in Swing-worker thread. In my example javax.swing.Timer action is performed in that thread, so i don't need to worry about it.
In other cases you should execute code inside:
SwingUtilities.invokeLater ( new Runnable ()
{
public void run ()
{
// Code here
}
} );
or:
SwingUtilities.invokeAndWait ( new Runnable ()
{
public void run ()
{
// Code here
}
} );
Depending on the situation.
It is not necessary but highly recommended, since Swing is not Thread-safe and you could get lots of problems later, when your application will grow wide.