I am wondering why the drawing area I have created is not showing up in my second panel. I have checked their locations uses getX and getY (250, 0, which is I am assuming the correct area for it to be since that would be the top left of the second panel), but I cannot seem to figure out what is wrong. I'm assuming this is a problem with some fundamental learning aspect of this that I do not have right, but cannot seem to figure out what the issue is. If you could explain to me what is going wrong and the proper direction as to where I would go about fixing it, that would be appreciated. I do have the drawing area working when I have it standalone; the issue is that I cannot get it to appear when working with other GUI components.
Thank you ^^
Code:
package Drawing;
import java.awt.Color;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class DrawingApp extends JFrame{
public static void main(String[] args) {
GridLayout grid = new GridLayout(1, 2);
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final DrawingComponent drawingArea = new DrawingComponent();
drawingArea.setSize(600, 250);
JPanel leftPanel = new JPanel();
JPanel rightPanel = new JPanel();
JSlider greSlider = new JSlider();
JSlider bluSlider = new JSlider();
JSlider redSlider = new JSlider();
Point leftLocation = new Point(0, 0);
Point rightLocation = new Point(250, 0);
JLabel greLabel = new JLabel("Green");
JLabel bluLabel = new JLabel("Blue");
JLabel redLabel = new JLabel("Red");
rightPanel.setLocation(rightLocation);
drawingArea.setLocation(rightLocation);
// JButton button = new JButton("Hello");
leftPanel.setSize(250, 600);
//leftPanel.setLocation(leftLocation);
leftPanel.setBorder((BorderFactory.createLineBorder(Color.black)));
rightPanel.setSize(250, 600);
//rightPanel.setLocation(rightLocation);
rightPanel.setBorder((BorderFactory.createLineBorder(Color.green)));
leftPanel.add(greLabel);
leftPanel.add(greSlider);
leftPanel.add(bluLabel);
leftPanel.add(bluSlider);
leftPanel.add(redLabel);
leftPanel.add(redSlider);
rightPanel.add(drawingArea);
frame.add(leftPanel);
frame.add(rightPanel);
//rightPanel.add(button);
frame.setSize(500, 600);
frame.setLayout(grid);
leftPanel.setVisible(true);
rightPanel.setVisible(true);
frame.setVisible(true);
class SlideClickListener implements ChangeListener
{
ChangeListener slideListener = new ChangeListener(){
#Override
public void stateChanged(ChangeEvent e){
if(e.getSource() == greSlider){
}
}
};
public void stateChanged(ChangeEvent ce) {
throw new UnsupportedOperationException("Not supportedyet.");
}
}
class MouseClickListener implements MouseListener
{
public void mouseClicked(MouseEvent event)
{
int x = event.getX();
int y = event.getY();
System.out.println(x + " " + y);
drawingArea.drawPoints(x,y);
}
// Donothing methods
public void mouseReleased(MouseEvent event) {}
public void mousePressed(MouseEvent event) {}
public void mouseEntered(MouseEvent event) {}
public void mouseExited(MouseEvent event) {}
}
MouseListener listener = new MouseClickListener();
drawingArea.addMouseListener(listener);
}
}
I can include the DrawingComponent class if needed, but assuming that it isn't since I know for sure that the class is working.
I'm assuming this is a problem with some fundamental learning aspect of this that I do not have right,
You don't appear to understand how layout managers work:
leftPanel.setSize(250, 600);
//leftPanel.setLocation(leftLocation);
rightPanel.setSize(250, 600);
//rightPanel.setLocation(rightLocation);
None of those statements will do anything. It is the job of the layout manager to determine the size and location of components added to the panel. In your case you are trying to use a GridLayout. So the components added to the grid will be given a size AFTER the decorations of the frame are taken into consideration. So even though the frame may be (500, 600), the space available to the panel will be less (because you need to account for the title bar and borders of the frame).
Also, you should assign the layout manager to the panel BEFORE you add components to the panel.
leftPanel.setVisible(true);
rightPanel.setVisible(true);
Swing components (except top level containers like JFrame, JDialog) are visible by default so the above code does nothing.
I can include the DrawingComponent class if needed,
Until a problem is solved you don't know what is or isn't relative to the problem. My guess is the your DrawingComponent is the problem. Again, the default layout manager of a JPanel is the FlowLayout which respects the preferred size of any component added to it. I'm guessing your DrawingPanel doesn't implement the getPreferredSize() method to the preferred size is (0, 0) so there is nothing to paint.
Read the section from the Swing tutorial on Custom Painting for more information and working examples to get you started.
I would suggest you also look at the Layout Managers section of the tutorial for layout basics and working examples.
Related
I'm just learning java and I have a project where I want to be able to move a JLabel around a window with my mouse.
I set up a class called BasicWindow1, implemented a MouseMotionListener, instantiated a JFrame container, added a JLabel to the JFrame, set up a mouseDragged method, hooked up the setBounds method of the JLabel to the MouseEvent information, compiled it and it ran ...
BUT ......
when I dragged the JLabel a second GHOST label appeared above it and moved happily along with its virtual brother.
I've included the code below and I'm hoping someone will take an interest and straighten me out. I'm guessing it's probably a simple beginner's mistake, but it's driving me crazy.
On the debugging level, I inserted a println(e) with the MouseEvent in the mouseDragged method and it showed that the MOUSE_DRAGGED x,y elements were oscillating between 2 distinct x,y paths, one for the GHOST and one for its virtual brother.
Thanks for looking,
Mike
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class BasicWindow1 implements MouseMotionListener {
JFrame jf = new JFrame();
JLabel label2 = new JLabel("label2");
public BasicWindow1(String string) {
//JFrame
jf.setTitle(string);
jf.setSize(400,400);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setLayout(null);
jf.setVisible(true);
label2.setOpaque(true);
label2.setBackground(Color.cyan);
label2.setBounds(0,150,75,25);
label2.addMouseMotionListener(this);
jf.add(label2);
}//end constructor
public void mouseDragged(MouseEvent e) {
label2.setBounds(e.getX(),e.getY(),75,25);
System.out.println("e = " + e);
}
public void mouseMoved(MouseEvent e) {}
public static void main(String[] args) {
BasicWindow1 mybw = new BasicWindow1("Basic Window for Stack Overflow");
}
}
Your problem is that you added the MouseMotionListener to the wrong component. You need to add it to the parent of label2, which is the content pane of jf.
Try the following code.
import java.awt.Color;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class BasicWindow1 implements MouseMotionListener {
JFrame jf = new JFrame();
JLabel label2 = new JLabel("label2");
public BasicWindow1(String string) {
// JFrame
jf.setTitle(string);
jf.setSize(400, 400);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setLayout(null);
jf.setVisible(true);
label2.setOpaque(true);
label2.setBackground(Color.cyan);
label2.setBounds(0, 150, 75, 25);
jf.getContentPane().addMouseMotionListener(this); // CHANGE HERE
jf.add(label2);
}// end constructor
public void mouseDragged(MouseEvent e) {
label2.setLocation(e.getX(), e.getY()); // CHANGE HERE
}
public void mouseMoved(MouseEvent e) {
}
public static void main(String[] args) {
BasicWindow1 mybw = new BasicWindow1("Basic Window for Stack Overflow");
}
}
Method getX() and getY(), in class MouseEvent, return the location of the mouse pointer in the coordinate space of the component that you added the MOuseMotionListener to. In your case this is the location of the mouse pointer inside the JLabel but that's not what you want. You want the location of the mouse pointer in the coordinate space of the component that you want to drag the JLabel around in which is the JFrame or more precisely the content pane of the JFrame.
For an alternative solution, refer to dragging a jlabel around the screen
This should be simple enough, yet I can't make it work.
I have two classes, one which should draw a circle, and the other which sets up a frame and panel with a button. On clicking the button, a circle should appear on the frame. I am confused as to why it doesn't appear. It's probably something very simple, sorry.
package ballsOnPane;
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.JPanel;
public class Display implements ActionListener{
private JFrame frame;
private JPanel panel;
private JButton button;
public static void main(String[] args) {
Display display = new Display();
}
public Display() {
frame = new JFrame();
frame.setSize(800, 500);
frame.setTitle("Show balls");
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
panel = new JPanel();
frame.add(panel, BorderLayout.CENTER);
button = new JButton("New Ball");
frame.add(button, BorderLayout.SOUTH);
button.addActionListener(this);
}
#Override
public void actionPerformed(ActionEvent e) {
Ball ball = new Ball(100, 100, 50);
panel.add(ball);
}
}
and ball class:
package ballsOnPane;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import javax.swing.JPanel;
public class Ball extends JPanel{
private int x;
private int y;
private int r;
public Ball(int x, int y, int r){
this.x = x;
this.y = y;
this.r = r;
}
public void paintComponent(Graphics g) {
Graphics2D g2 =(Graphics2D) g;
Ellipse2D circ = new Ellipse2D.Float(x, y, r, r);
g2.draw(circ);
}
}
When you add components to a visible GUI the basic code is:
panel.add(...);
panel.revalidate(); // to invoke the layout manager
panel.repaint(); // to repaint the components
Otherwise the size of the components added is (0, 0) so there is nothing to paint. The same goes for the button. It should be added BEFORE the frame is visible, or you need to do the revalidate()/repaint() as well.
In this case you also have a second problem:
frame.add(panel, BorderLayout.CENTER);
First you add an empty panel to the CENTER of the BorderLayout, then when you click the button you add the Ball to the CENTER.
Swing will paint the last component added first. So the ball gets painted and then the empty panel gets painted over top.
Get rid of the panel, it serves no purpose.
Edit:
For some reason I thought you were adding the Ball to the frame instead of the panel when you clicked the button.
My explanation above was correct if you did in fact add the Ball directly to the frame.
However, my explanation is incorrect since your code in the ActionListener does add the Ball to the panel. The proper explanation is below.
When you add the Ball to the panel, you don't see the Ball because by default a JPanel uses a FlowLayout and the FlowLayout respects the preferred size of any component added to it. You did not implement the getPreferredSize() method so the size is (0, 0) so there is nothing to paint.
So if you do implement the getPreferredSize() method in your Ball class the Ball will dislay on the panel. Also, you will be able to display a new Ball every time you click on the button.
As camickr answered, you need to revalidate() (or call both invalidate() & validate(), both will work) and then repaint() the panel.
The invalidate method marks the panel as being ''incorrect''; basically marking it for inspection.
Validate performs the layout of the component.
Revalidate does both, however, validate is synchronous whilst revalidate is not.
After you've validated the panel, you'll need to call repaint to redraw that panel.
As a side-note, JavaFX is replacing Swing/AWT, and in my opinon, is easier to use. You may want to look into it. :)
A short code example to do something similar to what you're currently doing, in JavaFX:
public class test extends Application{
Scene scene;
#Override
public void start(Stage primaryStage) throws Exception{
StackPane root = new StackPane();
root.setBackground(
new Background(new BackgroundFill(Color.ALICEBLUE,null,null)));
Button begin = new Button("Add Circle");
begin.setOnAction((ActionEvent e)->{
Circle c = new Circle(200,200,100,Color.RED);
root.getChildren().add(c);
});
root.getChildren().add(begin);
scene = new Scene(root, 700, 700);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
it's my first post so I hope it'll not be too cringeworthy. So I am trying to create a hex-based strategy game, not quite there yet but anyways.
To achieve a hex-based game I would like to create a field made of hexes which the user should be able to click, and receive the coordinates of that pixel. At the moment I can produce either a field of hexes or a mouselistener/mouseadapter but not both. The last one executed replaces the other on the screen.
If the pane.add(New HexMap()); is switched with pane.add(new MouseListener()); the listener works but the line is not printed
I've looked around for quite some time but the posts that I've encountered had either dealt with changing the background color which the mouselistener can do, because background is independent of the mousesensorhttp://docs.oracle.com/javase/tutorial/uiswing/events/mouselistener.html? The other examples I've come by have been too advanced for me, because they're using multiple panes, and I have not been able to comprehend themhttp://docs.oracle.com/javase/tutorial/uiswing/components/layeredpane.html.
So what I'm looking for is a way to add a mouselistener over a single pane, displaying the hexes. Would this be possible?
E.G adding the hexMap after the mouselistener would not overwrite the mouselistener but rather act as an addition
A single line has been created acting as a placeholder for the hexes.
The code:
import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.util.*;
import java.util.List;
import javax.swing.*;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
public class GraphicsSetup extends JPanel{
public static final int FRAME_WIDTH = 600;
public static final int FRAME_HEIGHT= 400;
private static JFrame frame;
public static void main(String[] args){
GraphicsSetup draw = new GraphicsSetup();
}
public GraphicsSetup(){
HexMap hexMap = new HexMap();
JPanel panel = new JPanel();
frame = new JFrame("HexExample");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(FRAME_WIDTH,FRAME_HEIGHT);
Container pane = frame.getContentPane();
pane.setBackground(new Color(20, 100, 30));
pane.add(new MouseListener());
pane.add(new HexMap());
frame.setVisible(true);
}
public class HexMap extends JComponent{
public void paint(Graphics g){
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.blue);
g2d.drawLine(0,0, FRAME_WIDTH, FRAME_HEIGHT);
}
}
class MouseListener extends JComponent{
public MouseListener(){
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent me) {
System.out.println("Mouse Event" + me);
}
});
}
}
}
Yours Sincerely
I'm not entirely sure what you're after, but try adding your components to your panel object. Such as:
panel.add(new MouseListener());
panel.add(new HexMap());
And then add this to the content pane of your frame:
pane.add(panel);
If you're wondering how to arrange your interface differently, read about layout managers here:
http://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
Edit
Try the following:
Set the layout manager to use a BorderLayout:
JPanel panel = new JPanel(new BorderLayout());
Add your components to the panel and set their location:
panel.add(new MouseListener(), BorderLayout.NORTH);
panel.add(new HexMap(), BorderLayout.CENTER);
Add the panel to the frame content pane:
pane.add(panel);
This will work but the size of the MouseListener panel is quite small...you'll need to figure that out next...
I'm trying to write custom JFrame and JPanel for my Java application. Currently, I just want to have a JPanel with a start button in the very middle of the screen. So, here's the code I have:
package gui;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
#SuppressWarnings("serial")
public class SubitizingFrame extends JFrame implements KeyListener {
public SubitizingFrame() {
super("Subitizing");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
addKeyListener(this);
add(new LaunchPanel());
pack();
setVisible(true);
}
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_F5)
System.out.println("F5 pressed");
}
public void keyReleased(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
}
}
and here is my panel:
package gui;
import instructions.Settings;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class LaunchPanel extends JPanel implements ActionListener {
private JButton startButton;
public LaunchPanel() {
int width = Settings.getScreenSizeX(), height = Settings.getScreenSizeY();
setPreferredSize(new Dimension(width, height));
setLayout(null);
startButton = new JButton("Start");
startButton.setLocation((width/2) - (startButton.getWidth()/2), (height/2) - (startButton.getHeight()/2));
add(startButton);
}
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
}
}
But when the application launches, I don't see anything. Just a big gray screen.
Do not use a null layout. If you simply use the default layout manager of JPanel (i.e. FlowLayout), the JButton with "automagically" be placed in the center. Also, in order to place the JFrame in the middle of the screen, invoke setLocationRelativeTo(null).
Since it's hard to tell what you mean by "screen", this example shows how you center a JButton in a JPanel in a JFrame, that is then centered on the monitor.
public final class CenterComponentsDemo {
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI(){
final JFrame frame = new JFrame("Center Components Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ButtonPane());
frame.setSize(new Dimension(300, 100)); // Done for demo
//frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private static class ButtonPane extends JPanel{
public ButtonPane(){
super();
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
setBackground(Color.PINK);
final JButton button = new JButton("Start");
button.setAlignmentX(Component.CENTER_ALIGNMENT);
add(Box.createVerticalGlue());
add(button);
add(Box.createVerticalGlue());
}
}
}
Recommendations:
Avoid using null layout as this makes your app difficult to upgrade and maintain and makes it potentially very ugly or even non-usable on boxes with different OS's or screen resolutions.
If you have your JPanel use a GridBagLayout and add a single component to it without using GridBagConstraints, it will be placed in the center of the JPanel.
You almost never have to or should extend JFrame and only infrequently need to extend JPanel. Usually it's better to enhance your GUI classes through composition rather than inheritance.
Avoid having your "view" or gui classes implement your listener interfaces. This is OK for "toy" programs, but as soon as your application gains any appreciable size or complexity, this gets hard to maintain.
If you don't use any LayoutManager (which btw you probably should), then you'll need to set the size of the panel as well (along with its position).
Although we strongly recommend that you use layout managers, you can perform layout without them. By setting a container's layout property to null, you make the container use no layout manager. With this strategy, called absolute positioning, you must specify the size and position of every component within that container. One drawback of absolute positioning is that it does not adjust well when the top-level container is resized. It also does not adjust well to differences between users and systems, such as different font sizes and locales.
From: http://download.oracle.com/javase/tutorial/uiswing/layout/using.html
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
public class LaunchPanel extends JPanel {
private JButton startButton;
public LaunchPanel() {
int width = 200, height = 100;
setPreferredSize(new Dimension(width, height));
setLayout(new GridBagLayout());
startButton = new JButton("Start");
add(startButton);
setBorder( new LineBorder(Color.RED, 2));
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JOptionPane.showMessageDialog(null, new LaunchPanel());
}
});
}
}
addKeyListener(this);
Don't use KeyListeners. Swing was designed to be used with Key Bindings. Read the section from the Swing tutorial on How to Use Key Bindings for more information.
The tutorial also has a section on Using Layout Manager which you should read. You should not create GUI's with a null layout.
I have only JTabbedPane inside JFrame. JTabbedPane sets its dimensions to biggest page width/height.
As pages has different size is it possible to force JTabbedPane to change its dimensions when selecting other page?
http://grab.by/3hIg
Top one is how it behave now and bottom one is how i want it to behave (i resized frame by hand)
This is fairly simple. It involves dynamic calculation of differences between your pages dimensions and the using them to force preferred size on you JTabbedPane. I did a quick experiment and it worked. So instead of putting a lot of text here - here is the code. It is not perfect but you should get an idea. Questions are welcome, of course.
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Test {
private static int maxW = 0;
private static int maxH = 0;
public static void main(String[] args) {
final JFrame f = new JFrame();
final JTabbedPane tabs = new JTabbedPane();
tabs.add( createPanel(Color.RED, 100, 100), "Red");
tabs.add( createPanel(Color.GREEN, 200, 200), "Green");
tabs.add( createPanel(Color.BLUE, 300, 300), "Blue");
final Dimension originalTabsDim = tabs.getPreferredSize();
tabs.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
Component p = ((JTabbedPane) e.getSource()).getSelectedComponent();
Dimension panelDim = p.getPreferredSize();
Dimension nd = new Dimension(
originalTabsDim.width - ( maxW - panelDim.width),
originalTabsDim.height - ( maxH - panelDim.height) );
tabs.setPreferredSize(nd);
f.pack();
}
});
f.setContentPane(tabs);
f.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private static final JPanel createPanel( Color color, int w, int h ) {
JPanel p = new JPanel();
p.setBackground(color);
p.setPreferredSize( new Dimension(w, h));
maxW = Math.max(w, maxW);
maxH = Math.max(h, maxH);
return p;
}
}
I think another option is to dynamically change the panels of each tab when the tab is selected:
install a listener on JTabbedPane selection
install an empty panel on every tab but the selected tab by default (that contains the real panel for that tab)
in the selection listener:
remove the panel from the previously selected tab (ie, replace it with an empty panel)
change the empty panel by the real panel in the newly selected tab
call pack() on the window/dialog containing the JTabbedPane
Disclaimer: I haven't tested this approach but I believe it should work according to what you want.
Please also note that dynamically changing the size of the dialog based on the selected tab is not very user-friendly from a pure GUI viewpoint.
How about this?
tabbedPane.addChangeListener(new ChangeListener(){
#Override
public void stateChanged(ChangeEvent arg0) {
Component mCompo=tabbedPane.getSelectedComponent();
tabbedPane.setPreferredSize(mCompo.getPreferredSize());
BasicFrame.this.pack();
}
});