createTransferable for JLabel or JPanel does not fire - java

Scaled back a sample I found to test working with JPanel and JLabel.
A new TransferHandler object is created for the createTransferable() call for both JPanel and JLabel.
Since there is no setDraggable method so I included the exportAsDrag (which is what I think is required if the object doesn't have the setDraggable method).
Although createTransferable() returns null and won't really do anything I should at least get the println executed, but the code doesn't seem to enter that section which means neither the panel or label is seen as a draggable object.
What is the missing step to get this to be seen as a draggable object.
And if you have a panel with a bunch of labels is it recommended to make the panel draggable and sort out which label or make each individual label draggable?
import java.awt.*;
import java.awt.datatransfer.Transferable;
import javax.swing.*;
import java.awt.event.InputEvent;
public class DnDTransferableTest {
public static void main(String[] args) {
new DnDTransferableTest();
}
public DnDTransferableTest() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JLabel label1;
private JLabel label2;
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.weighty = 1;
gbc.weightx = 1;
gbc.fill = GridBagConstraints.BOTH;
label1 = new JLabel("Drag Me.");
add(label1, gbc);
label2 = new JLabel("Drag Me too.");
gbc.gridx++;
gbc.weightx = 1;
gbc.fill = GridBagConstraints.NONE;
add(label2, gbc);
setTransferHandler(new TransferHandler()
{
#Override
public Transferable createTransferable(final JComponent c)
{
System.out.println("Inside Panel : createTransferable");
return null;
}
#Override
public int getSourceActions(final JComponent c)
{
System.out.println("Inside Panel : getSourceActions()");
return COPY;
}
#Override
public void exportAsDrag(final JComponent comp, final InputEvent e, final int action)
{
System.out.println("Inside Panel : getSourceActions()");
super.exportAsDrag(comp, e, action);
}
});
label1.setTransferHandler(new TransferHandler()
{
#Override
public Transferable createTransferable(final JComponent c)
{
System.out.println("Inside Label : createTransferable");
return null;
}
#Override
public int getSourceActions(final JComponent c)
{
System.out.println("Inside Label : getSourceActions()");
return COPY;
}
#Override
public void exportAsDrag(final JComponent comp, final InputEvent e, final int action)
{
System.out.println("Inside Label : getSourceActions()");
super.exportAsDrag(comp, e, action);
}
});
}
}
}

I think that you will need a MouseListener to allow the JLabel to accept a drag gesture since it does not have a setDragEnabled(...) method.
To use a MouseListener with your DnD:
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.Box;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.TransferHandler;
public class DnDTransferableTest {
public static void main(String[] args) {
new DnDTransferableTest();
}
public DnDTransferableTest() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JLabel label3;
private JTextField textField = new JTextField(15);
public TestPane() {
label3 = new JLabel("Fubars Rule!");
add(label3);
add(Box.createHorizontalStrut(35));
add(textField);
label3.setTransferHandler(new TransferHandler("text"));
label3.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent mEvt) {
JComponent component = (JComponent) mEvt.getSource();
TransferHandler tHandler = component.getTransferHandler();
tHandler.exportAsDrag(component, mEvt, TransferHandler.COPY);
}
});
}
}
}

Related

Button in CardLayout not working

So I'm using cardLayout in one of my programs and I'm trying to make it so that when you click a button the next panel loads. I have a panelHolder class where the cardlayout is held and every time the button on the panel is pressed, it would call a method in the panelHolder class that depending on the button sets a certain boolean variable to true and calls repaint (where the panels are shown). For some reason my button isn't working and I can't seem to find out why. Can someone help me?
import java.awt.*;
import java.awt.event.*;
import java.io.File;
import java.util.Arrays;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;
import javax.swing.*;
public class SheetReader101 extends JFrame {
public SheetReader101(){
super("SheetReader101");
setSize(2000,1000);
setLocation(0,0);
setResizable(true);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
PanelHolder pg2 = new PanelHolder();
setContentPane(pg2);
setVisible(true);
}
public static void main(String[]args){
SheetReader101 z1 = new SheetReader101();
}
}
class PanelHolder extends JPanel { // HERE
CardLayout clayout = new CardLayout();
PianoGameContent x;
tutorial y;
boolean [] paneldecide;
PanelHolder() {
super();
y = new tutorial();
x = new PianoGameContent();
setLayout(clayout);
this.add("Tutorial", y);
this.add("FreePlay Mode", x);
paneldecide = new boolean[15];
}
public static void main(String[]args){
PanelHolder z1 = new PanelHolder();
z1.run();
}
public void run(){
layoutShower(0);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
}
public void layoutShower (int decide){
{
PianoGameContent y2 = new PianoGameContent();
PanelHolder.this.add("Piano", y2);
System.out.println("intro slide run");
if(decide == 1){
PanelHolder.this.add("Piano", y2);
System.out.println("testing11");
clayout.show(PanelHolder.this,"Piano");
}
}
}
}
I "suspect" that the core problem has to do with the original code you posted, where you're making a new instance of PanelHolder in your child view's ActionListener and then are attempting to switch views, this new instance has no relationship to the instance that is on the screen.
There are a few ways you can manage CardLayout, my preferred way is to use some kind of "navigation" controller which defines how navigation works, for example, you could have "next" and "previous" or "back", or you could define the actual views that can be displayed, ie showMenuView, showTutorialView etc, depending on how much control you want to give your sub views.
The following is a simple example which demonstrates the basic idea, it uses a enum to define the available views (as it has more meaning than 0, 1... and I don't need to remember the actual names of the views, the IDE can provide auto correct for that ;))
I create and add each view up front when I create the PanelHolder, I also pass each view an instance of the NavigationController, so they can interact with it
import java.awt.CardLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class JavaApplication1013 {
public static void main(String[] args) {
new JavaApplication1013();
}
public JavaApplication1013() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new PanelHolder());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public enum View {
MENU,
TUTORIAL,
FREEPLAY;
}
public interface NavigationController {
public void showView(View view);
}
public class PanelHolder extends JPanel implements NavigationController {
private CardLayout cardLayout;
public PanelHolder() {
cardLayout = new CardLayout();
setLayout(cardLayout);
add(new MenuView(this), View.MENU.name());
add(new TutorialView(this), View.TUTORIAL.name());
add(new FreePlayView(this), View.FREEPLAY.name());
}
#Override
public void showView(View view) {
cardLayout.show(this, view.name());
}
}
public abstract class ViewPane extends JPanel {
private NavigationController controller;
public ViewPane(NavigationController controller) {
this.controller = controller;
}
public NavigationController getController() {
return controller;
}
protected void showView(View view) {
controller.showView(view);
}
}
public class MenuView extends ViewPane {
public MenuView(NavigationController controller) {
super(controller);
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.fill = GridBagConstraints.HORIZONTAL;
JButton tut = new JButton("Tutorial");
JButton freePlay = new JButton("Free Play");
add(tut, gbc);
add(freePlay, gbc);
tut.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
showView(View.TUTORIAL);
}
});
freePlay.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
showView(View.FREEPLAY);
}
});
}
}
public class TutorialView extends ViewPane {
public TutorialView(NavigationController controller) {
super(controller);
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
JButton menu = new JButton("Menu");
add(new JLabel("Tutorial"), gbc);
add(menu, gbc);
menu.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
showView(View.MENU);
}
});
}
}
public class FreePlayView extends ViewPane {
public FreePlayView(NavigationController controller) {
super(controller);
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
JButton menu = new JButton("Menu");
add(new JLabel("Free Play"), gbc);
add(menu, gbc);
menu.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
showView(View.MENU);
}
});
}
}
}
Take a closer look at How to Use CardLayout for more details

Repainting a JPanel

I have two frames with contents . The first one has a jlabel and jbutton which when it is clicked it will open a new frame. I need to repaint the first frame or the panel that has the label by adding another jlabel to it when the second frame is closed.
//Edited
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class FirstFrame extends JPanel implements KeyListener{
private static String command[];
private static JButton ok;
private static int count = 1;
private static JTextField text;
private static JLabel labels[];
private static JPanel p ;
private static JFrame frame;
public int getCount(){
return count;
}
public static void createWindow(){
JFrame createFrame = new JFrame();
JPanel panel = new JPanel(new GridLayout(2,1));
text = new JTextField (30);
ok = new JButton ("Add");
ok.requestFocusInWindow();
ok.setFocusable(true);
panel.add(text);
panel.add(ok);
text.setFocusable(true);
text.addKeyListener(new FirstFrame());
createFrame.add(panel);
createFrame.setVisible(true);
createFrame.setSize(600,300);
createFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
createFrame.setLocationRelativeTo(null);
createFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowEvent) {
System.out.println(command[count]);
if(command[count] != null){
p.add(new JLabel("NEW LABEL"));
p.revalidate();
p.repaint();
count++;
System.out.println(count);
}
}
});
if(count >= command.length)
count = 1;
ok.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
if(command[count] == null)
command[count] = text.getText();
else
command[count] = command[count]+", "+text.getText();
text.setText("");
}
});
}
public FirstFrame(){
p = new JPanel();
JButton create = new JButton ("CREATE");
command = new String[2];
labels = new JLabel[2];
addKeyListener(this);
create.setPreferredSize(new Dimension(200,100));
//setLayout(new BorderLayout());
p.add(new JLabel("dsafsaf"));
p.add(create);
add(p);
//JPanel mainPanel = new JPanel();
/*mainPanel.setFocusable(false);
mainPanel.add(create);
*/
create.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
createWindow();
}
});
//add(mainPanel, BorderLayout.SOUTH);
}
public static void main(String[] args) {
frame = new JFrame();
frame.add(new FirstFrame());
frame.setVisible(true);
frame.pack();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}
#Override
public void keyReleased(KeyEvent e) {
}
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_ENTER)
if(ok.isDisplayable()){
ok.doClick();
return;}
}
}
}
});
}
}
As per my first comment, you're better off using a dialog of some type, and likely something as simple as a JOptionPane. For instance in the code below, I create a new JLabel with the text in a JTextField that's held by a JOptionPane, and then add it to the original GUI:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class FirstPanel2 extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = 300;
private JTextField textField = new JTextField("Hovercraft rules!", 30);
private int count = 0;
public FirstPanel2() {
AddAction addAction = new AddAction();
textField.setAction(addAction);
add(textField);
add(new JButton(addAction));
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class AddAction extends AbstractAction {
public AddAction() {
super("Add");
}
#Override
public void actionPerformed(ActionEvent e) {
String text = textField.getText();
final JTextField someField = new JTextField(text, 10);
JPanel panel = new JPanel();
panel.add(someField);
int result = JOptionPane.showConfirmDialog(FirstPanel2.this, panel, "Add Label",
JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);
if (result == JOptionPane.OK_OPTION) {
JLabel label = new JLabel(someField.getText());
FirstPanel2.this.add(label);
FirstPanel2.this.revalidate();
FirstPanel2.this.repaint();
}
}
}
private static void createAndShowGui() {
FirstPanel2 mainPanel = new FirstPanel2();
JFrame frame = new JFrame("My Gui");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Also, don't add KeyListeners to text components as that is a dangerous and unnecessary thing to do. Here you're much better off adding an ActionListener, or as in my code above, an Action, so that it will perform an action when the enter key is pressed.
Edit
You ask:
Just realized it is because of the KeyListener. Can you explain please the addAction ?
This is functionally similar to adding an ActionListener to a JTextField, so that when you press enter the actionPerformed(...) method will be called, exactly the same as if you pressed a JButton and activated its ActionListener or Action. An Action is like an "ActionListener" on steroids. It not only behaves as an ActionListener, but it can also give the button its text, its icon and other properties.

how to make JButton show a list of JButtons with just few items

Hey Guys my problem is when I place the mouse on a JButton in my JFrame, I want it to show a list of JButtons on its left.
I don't known how to do that really I feel like I'm blocked and I cant make any progress in my project.
I'd would be grateful if you could help me and thanks in advance.
Can you create the list of buttons in a JPanel, add it to your JFrame and then call myPanel.setVisible(false). When you click your button then call myPanel.setVisible(true)?
As for ensuring that myPanel is positioned correctly you will want to use a Layout Manager
Or is there a more complex behaviour you want?
A basic option would be to use a MouseListener and a CardLayout. The MouseListener would be used to determine when the mouse cursor enters/exists a given component and the CardLayout would be used to display the appropriate sub component for each "menu" element.
I have to say, JButton would be me last choice for the "menu" item, in most cases, a JLabel would be preferred or even perhaps using a JMenu, which can can have sub menus, which can be displayed automatically might be a better choice, or even a JComboBox....
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class ShowStuff {
public static void main(String[] args) {
new ShowStuff();
}
public ShowStuff() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
MenuPane menu = new MenuPane();
menu.addMenu("Fruit", new FruitPane());
menu.addMenu("Meat", new MeatPane());
menu.addMenu("Dairy", new DairyPane());
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(menu);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MenuPane extends JPanel {
private JPanel subMenu;
private JPanel menu;
private CardLayout cardLayout;
private MouseListener mouseHandler;
public MenuPane() {
setLayout(new BorderLayout());
cardLayout = new CardLayout();
subMenu = new JPanel(cardLayout);
menu = new JPanel(new GridBagLayout());
add(subMenu);
add(menu, BorderLayout.WEST);
subMenu.add(new JPanel(), "BLANK");
mouseHandler = new MouseAdapter() {
#Override
public void mouseEntered(MouseEvent e) {
if (e.getSource() instanceof JButton) {
JButton btn = (JButton) e.getSource();
cardLayout.show(subMenu, btn.getText());
}
}
#Override
public void mouseExited(MouseEvent e) {
cardLayout.show(subMenu, "BLANK");
}
};
}
public void addMenu(String name, JPanel subMenuPane) {
JButton button = new JButton(name);
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
menu.add(button, gbc);
subMenu.add(subMenuPane, name);
button.addMouseListener(mouseHandler);
}
}
public abstract class ButtonPane extends JPanel {
private int gridy = 0;
public ButtonPane() {
setLayout(new GridBagLayout());
}
protected void addButton(String name) {
JButton btn = new JButton(name);
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = gridy++;
gbc.fill = GridBagConstraints.HORIZONTAL;
add(btn, gbc);
}
}
public class FruitPane extends ButtonPane {
public FruitPane() {
addButton("Banana");
addButton("Grapes");
addButton("Apples");
addButton("Tomatoes");
}
}
public class MeatPane extends ButtonPane {
public MeatPane() {
addButton("Lamb");
addButton("Beef");
addButton("Pork");
addButton("Mince");
}
}
public class DairyPane extends ButtonPane {
public DairyPane() {
addButton("Milk");
addButton("Cream");
addButton("Cheese");
addButton("Yoghurt");
}
}
}

JPanel in JApplet

I need to have one JPanel opened on start. I have a button on that one to open to another JPanel which contains a button to bring me back. How do i write action listeners for those buttons. I have searched extensively. Do I need a JFrame? All examples seem to have it.
Regardless of which approach you might take, the basic idea is the same. You need to know where to go based on where you are...
To this end, this simple example uses a simple navigation interface to provide movement control for the panels and a List to maintain the order of the components.
You could just as simply use a queue of some kind, pushing the next panel onto it and popping the last panel of it as you switched views.
This is a quick and simple example of CardLayout
import java.awt.CardLayout;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class SwitchPanel extends JApplet{
private String currentView;
private List<String> viewNames;
#Override
public void init() {
final CardLayout cardLayout = new CardLayout();
setLayout(cardLayout);
Navigator navi = new Navigator() {
#Override
public void next() {
int index = viewNames.indexOf(currentView);
if (index > -1) {
index++;
if (index < viewNames.size()) {
currentView = viewNames.get(index);
cardLayout.show(getContentPane(), currentView);
}
}
}
#Override
public void previous() {
int index = viewNames.indexOf(currentView);
if (index > -1) {
index--;
if (index >= 0) {
currentView = viewNames.get(index);
cardLayout.show(getContentPane(), currentView);
}
}
}
};
MainPane mainPane = new MainPane(navi);
LastPane lastPane = new LastPane(navi);
viewNames = new ArrayList<>(2);
viewNames.add("main");
viewNames.add("last");
add(mainPane, "main");
add(lastPane, "last");
currentView = "main";
cardLayout.show(getContentPane(), "main");
}
public interface Navigator {
public void next();
public void previous();
}
public class MainPane extends JPanel {
private Navigator navigator;
public MainPane(Navigator navi) {
this.navigator = navi;
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
JButton btn = new JButton("Next >");
add(new JLabel("Main"), gbc);
add(btn, gbc);
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
navigator.next();
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public class LastPane extends JPanel {
private Navigator navigator;
public LastPane(Navigator navi) {
this.navigator = navi;
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
JButton btn = new JButton("< Previous");
add(new JLabel("Last"), gbc);
add(btn, gbc);
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
navigator.previous();
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}

Layout method breaks after first execution

When the addComponents() method is run once, I get the desired layout of my JPanel. However, when the code in addComponents() is executed more than once, the layout of the JPanel is completely wrong. Is there anything that I seem to be doing wrong?
public class DeleteStudent extends JPanel {
public SearchPanel search = new SearchPanel();
private final JButton deleteButton = new JButton("Delete from database");
private GridBagConstraints cons = new GridBagConstraints();
private final GridBagLayout gridBag = new GridBagLayout();
public DeleteStudent() {
super();
setLayout(gridBag);
setPreferredSize(new Dimension(400, 300));
addComponents();
addComponents(); //Method fails when run more than once!
}
public void addComponents() {
cons.gridy = 1;
cons.insets = new Insets(50, 0, 0, 0);
gridBag.setConstraints(deleteButton, cons);
removeAll();
add(search);
add(deleteButton);
update();
}
private void update() {
revalidate();
repaint();
}
Screenshots:
JPanel after 1 method call: http://img402.imageshack.us/img402/6409/oncer.png
JPanel after 2 method calls: http://imageshack.us/scaled/landing/254/twiced.png
Adding to my comment:
Seems problem is you set the JPanels GridBagLayout constraints before calling removeAll() it should be done after calling removeAll(); so that when we add the new components the LayoutManager is still in effect and hasnt been reset to its defaults values.
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public Test() {
createAndShowGui();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Test();
}
});
}
private void createAndShowGui() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new DeleteStudent());
frame.pack();
frame.setVisible(true);
}
}
class DeleteStudent extends JPanel {
public JPanel search = new JPanel() {//for testing
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
};
private final JButton deleteButton = new JButton("Delete from database");
private GridBagConstraints cons = new GridBagConstraints();
private final GridBagLayout gridBag = new GridBagLayout();
public DeleteStudent() {
super();
setLayout(gridBag);
addComponents();
addComponents(); //Method fails when run more than once!
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
public void addComponents() {
removeAll();//must call this before resetting Layout and adding new components
cons.gridy = 1;
cons.insets = new Insets(50, 0, 0, 0);
gridBag.setConstraints(deleteButton, cons);
add(search);
add(deleteButton);
update();
}
private void update() {
revalidate();
repaint();
}
}

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