If I set up a JFrame with some components and a layout manager, which initially looks perfectly fine, and then later due to some condition (say, clicking a button) I hide one of those components - the layout manager shuffles all the components around again.
See example code - initially 3 buttons appear. When you click the Hide button, the Hide button is hidden - but the two outer buttons then squash together. When you click the show button, they move apart again to make space. How can I stop that from happening, so that after I call pack (), components stay where they are no matter if they later become hidden?
In my real code I'm doing this with GridBagLayout, but used FlowLayout in the example below because its simpler and less code, and shows exactly the same behaviour.
I can only think of nasty ways of doing this, like using .setEnabled (false) instead of .setVisible (false), and then overriding the component's paintComponent () method to not draw the component when it is disabled.
It seems the exact opposite problem to here - Hide a button from Layout in Java Swing - where is complaining that hidden buttons do still take up space :) But there's no sample code there to show it working in that way.
Many thanks for any suggestions :)
Example:
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class RevalidateWhenSetChildInvisibleExample
{
private JButton button1;
private JButton button2;
private JButton button3;
public void run ()
{
// Set up action
Action hideButtonAction = new AbstractAction ()
{
#Override
public void actionPerformed (ActionEvent e)
{
button2.setVisible (false);
}
};
hideButtonAction.putValue (Action.NAME, "Hide");
Action showButtonAction = new AbstractAction ()
{
#Override
public void actionPerformed (ActionEvent e)
{
button2.setVisible (true);
}
};
showButtonAction.putValue (Action.NAME, "Show");
// Set up buttons
button1 = new JButton ("Dummy");
button2 = new JButton (hideButtonAction);
button3 = new JButton (showButtonAction);
// Set up content pane
JPanel contentPane = new JPanel ();
contentPane.setLayout (new FlowLayout ());
contentPane.add (button1);
contentPane.add (button2);
contentPane.add (button3);
// Set up frame
JFrame frame = new JFrame ();
frame.setContentPane (contentPane);
frame.pack ();
frame.setVisible (true);
}
public static void main (String args [])
{
SwingUtilities.invokeLater (new Runnable ()
{
public void run ()
{
new RevalidateWhenSetChildInvisibleExample ().run ();
}
});
}
}
You could use a CardLayout and then swap the button with an empty JPanel.
Read the section from the Swing tutorial on How to Use CardLayout for more information and examples.
The problem is the layout manager, which is not really a problem here because it is just doing its job. You could set the layout to null and then set the bounds for every button; this way they will NEVER move unless you change their position.
panel.setLayout(null);
button1.setBounds(10,10,50,20);
button2.setBounds(70,10,50,20);
button3.setBounds(xPos,yPos,width,height);
Another way is to use the GridLayout:
contentPane.setLayout(new GridLayout());
I tested it, and it worked fine, since the component did not get removed it stays the same.
Also, you should add the following to your code:
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
This makes the program exits when the JFrame is closed; without it the program still runs at the background.
Related
I am a bit sorry to ask this question, since it seems to be a bit obvious, but I can't find my solution alone.
I am coding a little app in Java, and I encounter some issues "redrawing" my swing components. Basically, I want my JFrame to update when an event occurs. I managed to reproduced the issue in the code below. This code is supposed to display two buttons (which it does), and replace them with a third button when you click on the first button (which it doesn't).
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Example extends JFrame implements ActionListener {
private JButton button = new JButton("Button 1");
private JButton button2 = new JButton("Button 2");
private JButton button3 = new JButton("Button 3");
private JPanel buttons = new JPanel();
public void init() {
this.setVisible(true);
this.setSize(500,500);
buttons.add(button);
buttons.add(button2);
this.add(buttons);
this.button.addActionListener(this);
}
public void update() {
this.removeAll();
buttons.add(button3);
this.revalidate();
}
public static void main(String[] args) {
Example ex = new Example();
ex.init();
}
public void actionPerformed(ActionEvent e) {
if(e.getSource() == button) {
update();
}
}
}
I am pretty sure that I am doing something wrong in the update() method. I actually have a lot of trouble to understand how works removeAll(), revalidate(), repaint() etc, and I guess that is the problem. I tried to call the same methods on the buttons panel, it almost worked but I still have a graphic bug, and I would like to do it for all the container. I also tried to call these methods on this.getContentPane(), but it doesn't work.
Can anyone try to help me with it?
You're removing all components from this (which in this case is the JFrame (as you're extending it, which isn't needed, and instead you should create an instance from it rather than inherit from it, as you're not changing the behavior of the JFrame so it's better to just create an instance of it). See: Extends JFrame vs. creating it inside the program
In this case you're adding your components in this way:
JFrame > buttons (JPanel) > JButtons
And you're trying to remove
JFrame > everything
That includes the contentPane, instead you should call.
buttons.removeAll()
Inside the update() method.
And also call this.repaint() so your update() method should become:
public void update() {
buttons.removeAll();
buttons.add(button3);
this.revalidate();
this.repaint();
}
Or the best approach is to use CardLayout as recommended by #AndrewThompson in the comment below. This way you don't have to handle removing / repainting for each component, as CardLayout will do it for you. For example
this works,
public void update() {
buttons.remove(button);
buttons.remove(button2);
buttons.add(button3);
this.revalidate();
this.repaint();
}
By analogy with ToolTipManager setDismissDelay(int milliseconds) method, i would like to implement a dismiss delay for the rollover effect on a JButton.
In my swing application i have set different icons for my JButtons (setIcon, setPressedIcon and setRolloverIcon methods), but i'm trying to solve an issue occurring when a particular JButton, which should open a modal dialog, is pressed.
When the button is pressed and the modal dialog is shown, the jbutton still shows the Rollover icon, even if i passed the "normal" icon to setPressedIcon method.
Also, the rollover icon won't disappear until the cursor returns to main frame, also if the jdialog has been closed.
I made an example to show what i mean. I placed only two buttons into main frame, each button has a green square icon as "normal" icon, and a red icon for rollover effect.
As i sayed, i would like the buttons to show again the green icon when they are pressed. The first button will behave "wrongly", since the red icon is visible after the jdialog creation.
For the second button i solved this issue overriding isPressed () method (in its DefaultButtonModel), by calling setRollover (false) when the button is pressed.
I don't think this is the best solution, i would prefer not to act directly on ButtonModel.
So i would like to know if you have a better idea, maybe something similar to a setDismissDelay method, as i sayd before. Thanks !
Here there's an SSCE :
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.DefaultButtonModel;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class SSCE
{
public static void main (String[] a) {
SwingUtilities.invokeLater (new Runnable () {
public void run () {
JFrame frame = new JFrame ("Icon Test");
frame.setContentPane (new MainPanel (frame));
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.setResizable (false);
frame.pack ();
frame.setLocationRelativeTo (null);
frame.setVisible (true);
}
});
}
}
class MainPanel extends JPanel
{
public MainPanel (JFrame parent) {
JButton firstButton = createButton (createButtonImage (Color.GREEN), createButtonImage (Color.RED), parent);
JButton secondButton = createButton (createButtonImage (Color.GREEN), createButtonImage (Color.RED), parent);
secondButton.setModel (new DefaultButtonModel () {
#Override public boolean isPressed () {
boolean isPressed = super.isPressed ();
if (isPressed) setRollover (false);
return isPressed;
}
});
add (firstButton);
add (secondButton);
}
private JButton createButton (BufferedImage normalImage, BufferedImage rolloverImage, final JFrame parent) {
ImageIcon normalIcon = new ImageIcon (normalImage), rolloverIcon = new ImageIcon (rolloverImage);
JButton button = new JButton (new AbstractAction () {
public void actionPerformed (ActionEvent e) {
JDialog dialog = new JDialog (parent, "Test Dialog",true);
dialog.setSize (400, 400);
dialog.setLocationRelativeTo (parent);
dialog.setVisible (true);
}
});
button.setBorderPainted (false);
button.setCursor (Cursor.getPredefinedCursor (Cursor.HAND_CURSOR));
button.setFocusPainted (false);
button.setContentAreaFilled (false);
button.setIcon (normalIcon);
button.setPressedIcon (normalIcon);
button.setRolloverEnabled (true);
button.setRolloverIcon (rolloverIcon);
return button;
}
private BufferedImage createButtonImage (Color color) {
BufferedImage image = new BufferedImage (20, 20, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics ();
g.setColor (color);
g.fillRect (0, 0, 20, 20);
g.dispose ();
return image;
}
}
EDIT :
As #camickr suggested, i tried to wrap the ActionListener code in a SwingUtilities.invokeLater ().
I won't repost the full code, i have only replaced those lines :
JButton button = new JButton (new AbstractAction () {
public void actionPerformed (ActionEvent e) {
JDialog dialog = new JDialog (parent, "Test Dialog",true);
dialog.setSize (400, 400);
dialog.setLocationRelativeTo (parent);
dialog.setVisible (true);
}
});
with :
JButton button = new JButton ();
button.addActionListener (new ActionListener () {
public void actionPerformed (ActionEvent e) {
SwingUtilities.invokeLater (new Runnable () {
public void run () {
JDialog dialog = new JDialog (parent, "Test Dialog",true);
dialog.setSize (400, 400);
dialog.setLocationRelativeTo (parent);
dialog.setVisible (true);
}
});
}
});
However, this doesn't solve my problem, the red icon is still visible when the dialog is created.
I tried some small adjustments, with addActionListener or setAction, also only calling setVisible into the invokeLater call, but it still doesn't work.
Also, how could i use a Timer without using the same code on ButtonModel which i am using now ?
I already tried some "hacks" by setting "normal icon" inside the actionPerformed and then invoking the other Action with a "custom" ActionEvent, but i would like to have a "clean" solution.
All code in a listener executes on the Event Dispatch Thread (EDT).
The problem is that the state of the button is not changed before the ActionListener code is invoked. Once the modal dialog is displayed, the button state change code isn't executed until the dialog is closed.
Wrap the code in the ActionListener in a SwingUtilities.invokeLater(). This code will be added to the end of the EDT allowing normal button processing to finish before the dialog is displayed.
Read the section from the Swing tutorial on Concurrency in Swing for more information about the EDT.
Edit:
i would prefer not to act directly on ButtonModel
Spend more time playing with the code. The problem is that there is no mouseExited that is generated when the dialog is displayed so the state of the ButtonModel is never updated.
Another option might be to manually generate a MouseEvent for the mouseExited event and dispatch the event to the button before the dialog is displayed.
Although this approach would also be considered a hack.
how could i use a Timer
Again, the problem is the state of the button. Even if you use a Timer you would manually need to reset the state of the model.
Your current solution seems reasonable since all the logic is located in a class that customizes the behaviour.
I'm new to Java programming and I'd like to know how to mess around with buttons, I have created a "Home Screen" and some buttons as well as text, however it's not as advanced as I'd like it to be, I want to know how to create things like image effects, so let's say I hover over a button, I want it to display a glowing animation behind it, or since I don't have that animation, if there's no easy way to create it, just displaying an image behind it is alright, also I don't have anything happening when pressing the button bcs IDK how to do that yet so if you could help with that it'd be awesome!
Here's the code I currently have:
package Menu;
import java.awt.FlowLayout;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class BackgroundPanel extends JFrame {
private BufferedImage image;
public BackgroundPanel() {
ImageIcon icon = new ImageIcon("image_path.png");
JButton btn = new JButton(icon);
btn.setOpaque(false);
btn.setContentAreaFilled(false);
btn.setBorderPainted(false);
btn.setFocusPainted(false);
try {
image = ImageIO.read(new File("image_path.jpg"));
// Set your Image Here.
this.setContentPane(new JLabel(new ImageIcon(image)));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
JPanel panel = new JPanel();
panel.add(new JLabel("Username:"));
panel.add(new JTextField("",20));
panel.add(new JLabel("Password:"));
panel.add(new JTextField("",20));
panel.add(btn);
//Adding components to Panel and JFrame
this.add(panel);
// JFrame Properties
this.setSize(1280,720);
this.setLayout(new FlowLayout());
this.setResizable(true);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("Panel");
this.setVisible(true);
}
public static void main(String[] args) {
new BackgroundPanel();
}
}
[...] also I don't have anything happening when pressing the button bcs IDK how to do that yet so if you could help with that it'd be awesome [...]
You need to add an ActionListener to your button. There are various other ways to detect if the button was pressed, but this one is the (in my opinion) easiest. This is how you do it:
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
// code you write in here will be executed if the button was pressed
}
});
[...] let's say I hover over a button, I want it to display a glowing animation behind it, or since I don't have that animation, if there's no easy way to create it, just displaying an image behind it is alright [...]
For this, you'll have to deal with JLayeredPanes and MouseListeners. Here is an example that I created "on the run"; the layouting is very dirty and has to be improved. Anyhow, you'll notice that once you hover over the button, a black-bordered box containing LA- -LL! will appear behind the button. That's a JLabel and you can use it to display images and such by using the JLabel.setIcon method.
let's say I hover over a button, I want it to display a glowing animation behind it, or since I don't have that animation, if there's no easy way to create it, just displaying an image behind it is alright
This is not that easy, it requires jumping through a whole bunch of hoops, especially when the button isn't rectangle.
A while I ago a did a prototype of a "validation highlighter" which highlighted invalid fields, it makes use of JXLayer library, but which should be convertible to use the included JLayer library on the core libraries
See How can I change the highlight color of a focused JComboBox for more details
The other possibility we'd be to create a custom JPanel and override its paintComponent method and paint your effect there. You would place your button it and with a combination of a a layout manager and borders you should be able to get the button positioned where you need it.
The problem with this, is it will effect the over layout of your form, as the effect will be considered while the primary form is laid out
I really don't have anything happening when pressing the button bcs IDK how to do that yet so if you could help with that it'd be awesome
I suggest you have a look at How to use buttons and How to write ActionListeners
in this code when the new button is clicked, the Jinternalframe goes behind the button, even if i add anything else like, jlabel, jtextfield, etc, the internalframe opens behind everything. i tried the tofront() and movetofront() functions, but it doesnt seem to work. plz help, thanks.
code:
import java.awt.BorderLayout;
import java.awt.CardLayout;
import javax.swing.JFrame;
import javax.swing.JButton;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class Messages2 extends JFrame {
JFrame frame;
JButton button1;
public static void main(String[] args) {
Messages2 window = new Messages2();
window.frame.setVisible(true);
}
public Messages2() {
frame = new JFrame();
frame.getContentPane().setBackground(Color.WHITE);
frame.setBounds(100, 100, 220, 220);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//frame.getContentPane().setLayout(new FlowLayout());
JButton btnNew = new JButton("New Message");
btnNew.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
JDesktopPane desktopPane = new JDesktopPane();
JInternalFrame intFrame = new JInternalFrame(
"JInternalFrame demo");
intFrame.setMaximizable(true);
intFrame.setIconifiable(true);
intFrame.setResizable(true);
intFrame.setClosable(true);
intFrame.setDefaultCloseOperation(JInternalFrame.DISPOSE_ON_CLOSE);
intFrame.setSize(320, 240);
// intFrame.pack();
intFrame.setVisible(true);
desktopPane.add(intFrame);
frame.add(desktopPane, BorderLayout.CENTER);
}
});
btnNew.setBounds(1, 35, 145, 31);
frame.getContentPane().add(btnNew);
}
}
when the new button is clicked, the Jinternalframe goes behind the button, even if i add anything else like, jlabel, jtextfield, etc,
Based on the code you posted in you last question (before you deleted it), you are attempting to add all your components directly to the frame. Swing paints components in the reverse order that a component is added. So since the internal frame is added last it is painted first and then all the other components are painted over top of it.
This is not the way you should be working with a JInternalFrame. You need to separate the JDesktopPane/JInternalFrames from your other components and work with each separately.
Read the section from the Swing tutorial on How to Use Internal Frames for basic information and examples.
the internal frame is added to a JDesktopPane which is added to the frame.
Don't use a null layout for your other components. Swing was designed to be used with layout managers. These components should be added to a panel and then the panel added to the frame.
The panel and the desktop pane must be added to different areas of the frame. For example:
frame.add(panel, BorderLayout.NORTH);
frame.add(desktopPane, BorderLayout.CENTER);
You're not using JInternalFrame correctly. It should only be placed within a JDesktopPane, something you're not doing and that I suggest that you start doing. Please check the appropriate tutorial on this.
Your button and your JInternalFrame now fill the field since you're using the JFrame's default BorderLayout. Suggestion:
First and foremost, explain fully just what exact effect/user experience you're trying to achieve. Are you sure that a JInternalFrame is your best choice here?
Learn about and use the layout managers to their best advantage.
If you're going to use a JInternalFrame, then while it's OK to add the JInternalFrame in your ActionListener, you're usually going to want to add the JDesktopPane to the GUI on GUI creation, not in the ActionListener.
I'm working on a project, and have run into a little bit of a logic error, hopefully one of you can clear this up.
I'm building an application that will display a SQL database (among other things). Currently, the way I have things set up, I have a JTabbedPane inside a Container (BorderLayout.CENTER) not that this is really pertinent information.
Anywho, I would like to add a tab once the user has connected to a database (and eventually selected which 'table' to see. For now however, there is only one table to be displayed.
So, when the user hits 'Connect', ideally the connection will be successful, at which point in time a JTable is populated with the database information.
Once this table is initialized and ready to go, add it to a new JPanel, and add that panel to the JTabbedPane.
This is where the error comes in. I 'believe' my logic thus far is correct, and I don't get any compiler/runtime errors, the new tab just isn't shown (and if I click where it should be) nothing happens.
Below is some of my code, if anything needs clarified please don't hesitate to ask!
This is the Table_Builder Class code (I will clean it up once it is working properly!)
public class Table_Builder extends Framework
{
private DefaultTableModel updated_table_model;
private JTable updated_table;
private JScrollPane table;
public Table_Builder()
{
// no implemention needed
}
public Table_Builder(Vector rows, Vector columns)
{
updated_table_model = new DefaultTableModel(rows, columns);
updated_table = new JTable(updated_table_model);
updated_table.setCellSelectionEnabled(true);
updated_table.setFillsViewportHeight(false);
table = new JScrollPane(updated_table);
JPanel tab2 = new JPanel();
tab2.add(table);
tab2.setVisible(true);
center.add("Table Viewer", tab2);
// I'm thinking some sort of listener needs to be active, so it knows I'm adding a new
// tab, but I'm not sure how this actually works.
center.addPropertyChangeListener("foregroud", null);
center.repaint();
// center has already been added to container so i don't think that needs to be done again?
}
Framework
protected void center_panel()
{
JPanel tab1 = new JPanel();
tab1.add(//emitted);
center.setPreferredSize(new Dimension(1340, 950));
center.setBackground(new Color(90, 90, 90));
center.addTab("Tab1", tab1);
container.add(center, BorderLayout.CENTER);
}
Best Regards,
Mike
UPDATE:
Framework has these variables I am using to build the 'Frame'
Framework is a borderlayout (east, west, north, south, center)
protected JTabbedPane center // this is the center panel
protected Container container // this will house all panels to be added
As seen above, I am currently adding tabs by
1.) creating a new JPanel
2.) adding (whatever needs to be displayed) to the jpanel
3.) adding that jpanel to the JTabbedPane
this is done by
center.addTab("Tab name here", panel to be added);
The javadoc for this says
center.addTab("String title", Component component);
This works as intended, the problem I am encountering, is that this is done prior to server connection. After the user connects to the server, I would like to add a new tab, which is being done from Table_Builder, which inherits from Framework (which is why center and container are protected and not private).
Your code for adding a tab in the constructor is the following:
JPanel tab2 = new JPanel();
tab2.add(table);
tab2.setVisible(true);
center.add("Table Viewer", tab2);
// I'm thinking some sort of listener needs to be active, so it knows I'm adding a new
// tab, but I'm not sure how this actually works.
center.addPropertyChangeListener("foregroud", null);
center.repaint();
There are 2 errors and a lot of unnecessary lines. The errors are:
center.add("Table Viewer", tab2); is using the add function of the Container class. When you wanted to use center.addTab("Table Viewer", tab2);.
Just to clear up what #peeskillet was pointing out, there is not a "foregroud" property, nor a "forground" (as per your comment), but a "foreground" property.
Now what you need to do is just the following:
JPanel tab2 = buildTableViewerTab();
center.addTab("Table Viewer", tab2);
Where buildTableViewerTab() (returning a JPanel) is the code necessary to create the JPanel that you desire. Just create the component and add it to the tabbedPane properly.
To show how this code works here is a simple executable application demonstrating this functionality. Again, what #peeskillet was asking you in his second comment is to do this same example but in your own way and with your code demonstrating the errors you were encountering. Although doing this you probably would have found them.
import java.awt.BorderLayout;
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.JTabbedPane;
import javax.swing.SwingUtilities;
public class AddTabsExample
{
public static final void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new AddTabsExample();
}
});
}
public AddTabsExample()
{
JFrame frame = new JFrame("Tab adder frame");
final JTabbedPane tabbedPane = new JTabbedPane();
frame.add(tabbedPane);
JButton addButton = new JButton("Add tab");
addButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent arg0)
{
JPanel newTabComponent = new JPanel();
int tabCount = tabbedPane.getTabCount();
newTabComponent.add(new JLabel("I'm tab " + tabCount));
tabbedPane.addTab("Tab " +tabCount, newTabComponent);
}
});
frame.add(addButton, BorderLayout.SOUTH);
addButton.doClick(); //add the first tab
frame.setSize(800, 300);//frame.pack();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setVisible(true);
}
}
Execution result:
call revalidate() on your center, then repaint.