Develop Reference

JLabel.setText() relocates all labels in mousewheelevent

EDIT: leaving short code which shows issue:
Then label.setText("") is called and it has to change the text, i.e. scaler overcame 50 barrier the label dissapears for the mousewheelevent -> re-emerges on next event. Also a problem of the label not being present on the Load-up.
In actual program labels stack together in 1 spot if any of them has .setText() changing value or .setVisible changing (These two methods I need to be able to use without affecting labels positioning)
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
import javax.swing.OverlayLayout;
public class brokenLabel extends JFrame
{
private JLayeredPane layerPane;
private JPanel breakingLabelPanel = new JPanel();
private JLabel label;
private int scaler = 50;
private int xstart = 200;
private int ystart = 200;
public static void main(String[] args)
{
#SuppressWarnings("unused")
brokenLabel program = new brokenLabel();
}
public brokenLabel()
{
// Frame setup used on the program
final JFrame frame = new JFrame("This is a slideshow");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
layerPane = new JLayeredPane();
frame.setContentPane(layerPane);
// Panel used (it's similar to what's added on the actual program)
breakingLabelPanel.setOpaque(true);
breakingLabelPanel.setLayout(new OverlayLayout(breakingLabelPanel));
breakingLabelPanel.setVisible(true);
breakingLabelPanel.setSize(getMaximumSize());
breakingLabelPanel.addMouseWheelListener(new MouseWheelListener(){
#Override
public void mouseWheelMoved(MouseWheelEvent arg0)
{
if (scaler > 5 || arg0.getWheelRotation() < 0)
scaler = scaler - 5*arg0.getWheelRotation();
setTexts();
}
});
//The testing label
label = new JLabel(new String("1"));
label.setLocation(xstart , ystart);
breakingLabelPanel.add(label);
frame.add(breakingLabelPanel,layerPane);
frame.setVisible(true);
//revalidate and repaint don't help make label visible on load-up
frame.revalidate();
frame.repaint();
}
public void setTexts(){
label.setLocation(xstart + scaler,ystart + 25);
if(scaler < 50)
{
label.setText("1");
}
else
{
label.setText("2");
}
}
}

JButton changes size

I have a JFrame, and whenever I switch from one JFrame using a JButton it starts out normally, but whenever I create a new instance of the first JFrame, the JButton is in an incorrect location and is the wrong size.
Example on startup
and when another one is created
Code:
public class Menu extends JFrame implements Runnable {
private static final long serialVersionUID = 1L;
public static int Number_of_Participants = 0;
protected JPanel window = new JPanel();
double p;
private JButton Participants;
private Rectangle rParticipants;
protected int Button_width = 240;
protected int Button_height = 48;
boolean running = false;
Thread thread;
JFrame frame = new JFrame();
public Menu() {
window.setBackground(Color.BLUE);
frame.setSize(new Dimension(800, 600));
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.getContentPane().add(window);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
Image image = null;
try {
image = ImageIO.read(new File("res/BG.jpg"));
} catch (IOException e) {
e.printStackTrace();
}
generateFiles();
drawButtons();
startMenu();
frame.repaint();
}
public void drawButtons() {
rParticipants = new Rectangle(520, 12, Button_width, Button_height);
Participants = new JButton("A");
Participants.setBounds(rParticipants);
window.add(Participants);
Participants.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
frame.dispose();
new Participant(Number_of_Participants);
}
});
}
}
Participant.java extends Menu.java
int Participant_ID;
public Participant(int Participant_ID) {
super();
this.Participant_ID = Participant_ID;
}
makes a JButton that goes back to Menu.java

As mentioned in the comment, your problem is most likely related to the call to setVisible(true). This should always be the LAST call in the constructor. Particularly, it should only be called AFTER all components have been added to the frame.
Apart from that, from the code that you posted, it seems like you want to switch through a seqence of frames, starting with a "main" menu, and then going through one frame for each "Participant". This intention could already be considered as questionable, because closing and disposing a JFrame just in order to create a new one does not seem to be very elegant. Most likely, a more elegant solution would be possible with a CardLayout : http://docs.oracle.com/javase/tutorial/uiswing/layout/card.html
However, some general hints:
Create the GUI on the Event Dispatch Thread
Don't extend JFrame. Instead, create a JFrame and fill it as needed
Don't implement Runnable with your top level class
Obey the standardJavaNamingConventions!
Don't try to do manual layouts with setBounds
This code is still not "beautiful", but at least shows how the goal of switching through several frames might be achieved, taking into account these points
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class MenuExample
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
JPanel mainMenuPanel = new MainMenuPanel();
createAndShowFrame(mainMenuPanel);
}
});
}
static void createAndShowFrame(JPanel panel)
{
JFrame frame = new JFrame();
frame.getContentPane().add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(800, 600));
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
static JButton createNextParticipantButton(
final JComponent container, final int nextID)
{
JButton nextParticipantButton = new JButton("New Participant");
nextParticipantButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
Window window =
SwingUtilities.getWindowAncestor(container);
window.dispose();
ParticipantPanel participantPanel =
new ParticipantPanel(nextID);
createAndShowFrame(participantPanel);
}
});
return nextParticipantButton;
}
}
class MainMenuPanel extends JPanel
{
public MainMenuPanel()
{
setBackground(Color.BLUE);
add(MenuExample.createNextParticipantButton(this, 0));
}
}
class ParticipantPanel extends JPanel
{
private final int participantID;
public ParticipantPanel(int participantID)
{
this.participantID = participantID;
add(new JLabel("Add the contents for participant "+participantID));
add(MenuExample.createNextParticipantButton(this, participantID+1));
}
}

Adding graphics into a JFrame using BorderLayout

I'm trying to do a simple piece of homework, where I display a line of text displaying whether a door object is open or not. Underneath that, I visually represent it (using the drawRect) method. And at the bottom I have two buttons, which can open or close the door, thus changing the text and rectangle.
Edit: List of code that can be compiled given now:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Test {
public static void main(String[] args) {
// Creates new JFrame called frame, with title "Door"
// (displayed at top of screen).
JFrame frame = new JFrame ("Door");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
TempDoorPanel panel = new TempDoorPanel();
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
}
class Door {
private String state;
private String message;
Door (String state) {
this.state = state;
message = "The door is currently closed.";
}
public boolean isOpen() {
return state.equals ("open");
}
public boolean isClosed() {
return state.equals ("closed");
}
public void setState(String state) {
this.state = state;
}
public String getMessage() {
return message;
}
public void open() {
if (state.equals("open")) {
message = "The door is already open.";
}
else {
state = "open";
message = "The door has been opened.";
}
}
public void drawOpenDoor (Graphics page) {
page.drawRect(100, 100, 100, 100);
}
}
class TempDoorPanel extends JPanel {
private Door door;
private JTextField currentStateOfDoor;
private JButton openDoor;
public TempDoorPanel() {
super.setLayout(new BorderLayout());
door = new Door("closed");
super.setBackground(Color.blue);
super.setPreferredSize(new Dimension (360, 400));
currentStateOfDoor = new JTextField(14);
currentStateOfDoor.setText(door.getMessage());
super.add(currentStateOfDoor, BorderLayout.NORTH);
openDoor = new JButton("Open Door");
class openDoorListener implements ActionListener {
public void actionPerformed (ActionEvent event) {
door.open();
repaintText();
}
}
openDoorListener openlistener = new openDoorListener();
openDoor.addActionListener(openlistener);
JPanel holder = new JPanel();
holder.add(openDoor);
super.add(holder, BorderLayout.SOUTH);
}
private void repaintText() {
currentStateOfDoor.setText(door.getMessage());
// These methods are from Door class.
}
public void paintComponent (Graphics page) {
super.paintComponent(page);
if (door.isOpen())
door.drawOpenDoor(page);
// isOpen is a boolean method from Door class.
}
}
What works:
Buttons appear at right place on screen, at BorderLayout.SOUTH, one after the other.
The JTextField appears at right place, at BorderLayout.NORTH
Finally, the blue area appears in the right place in the centre of the screen.
What I'm trying to fix:
I have no idea how to display the rectangle properly in the middle of that blue area. I've tried changing the coordinates and size of the rectangle, which doesn't change the size of it at all. I can make it drawRect(100, 100, 100, 100) and it changes nothing.
I'm also aware that the rectangle is currently hidden behind the top left corner of the JTextField, but I can't figure out how to move it into the BorderLayout.
Questions:
How do you place a rectangle in a BorderLayout?
How do you adjust the size of a rectangle, drawn via drawrect(), in such a layout?

Because you add components to the JPanel you draw on the JTextField is covering your drawing.
Solution:
1) Either compensate for this by checking the JTextField height in your drawRect(..) method
or better
2) Dont add components to the same JPanel which you are drawing on unless it cant be helped.
So basically I made your TempDoorPanel add a new JPanel to BorderLayout.CENTER which is the drawing panel we can now use drawRect(0,0,10,10) and it will show in the top left hand corner of JPanel drawingPanel.
Also dont call setPreferredSize on JPanel rather override getPreferredSize() and return Dimensions which fit your drawings.
To invoke paintComponent outside of the class simply call repaint() its instance
See this example which uses point no.2:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class Test {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Door");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
TempDoorPanel panel = new TempDoorPanel();
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
});
}
}
class Door {
private String state;
private String message;
public Door(String state) {
this.state = state;
message = "The door is currently closed.";
}
public void drawOpenDoor(Graphics page) {
page.setColor(Color.GREEN);
page.drawRect(0, 0, 10, 10);
}
}
class TempDoorPanel extends JPanel {
private Door door;
private JTextField currentStateOfDoor;
private JButton openDoor;
public TempDoorPanel() {
super.setLayout(new BorderLayout());
door = new Door("closed");
currentStateOfDoor = new JTextField(14);
//AcurrentStateOfDoor.setText(door.getMessage());
super.add(currentStateOfDoor, BorderLayout.NORTH);
openDoor = new JButton("Open Door");
final JPanel drawingPanel = new JPanel() {
#Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
// if (door.isOpen()) {
door.drawOpenDoor(grphcs);
// }
// isOpen is a boolean method from Door class.
}
};
drawingPanel.setBackground(Color.blue);
add(drawingPanel);
class openDoorListener implements ActionListener {
public void actionPerformed(ActionEvent event) {
//door.open();
repaintText();
drawingPanel.repaint();//so paint component of drawing panel is called
}
}
openDoorListener openlistener = new openDoorListener();
openDoor.addActionListener(openlistener);
JPanel holder = new JPanel();
holder.add(openDoor);
super.add(holder, BorderLayout.SOUTH);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
private void repaintText() {
// currentStateOfDoor.setText(door.getMessage());
// These methods are from Door class.
}
}

When you handler the door opening event with your listener;
class openDoorListener implements ActionListener {
public void actionPerformed(ActionEvent event) {
door.open();
repaintText();
}
}
you don't actually include a call to repaint the panel; hence the panel's paintComponent() method isn't called and door.drawOpenDoor() isn't called. You can test this by clicking the button and then resizing the frame. When you resize, the panel is automatically repainted and bingo, your door appears.
You can fix this by adding a call to repaint() in your ActionListener;
class openDoorListener implements ActionListener {
public void actionPerformed(ActionEvent event) {
door.open();
repaintText();
repaint(); // requests that the panel be repainted
}
}

KeyPressed and mousePressed Event in an unfocused Component

What are several ways of detecting a key stroke without the need of focusing on the component that the event was implemented? Here's my idea on this:
Even without focusing on myComponent, upon pressing a key, the action should take part. ** Same question for the mousePressed event. A mouse click will be detected even when not clicking on the component.**
myComponent.addKeyListener( new KeyAdapter() {
#Override
public void keyPressed( KeyEvent e ){
// My action here
}
});
Upon answering Question1, can it also be done even if the application is running on background? Say I have a browser, every time I click or press a key, the given action will be executed.
I also accept suggestions to read as an answer. If your answer would be KeyBinding related, please do elaborate. All answer and comments will be greatly appreciated.
I used JNativeHooks examples here and it works perfectly fine. Any other method by just Java alone?

For the first question, regarding the KeyStroke thingy, I guess you can use KeyBinding instead of using KeyListener, that can give you the desired result, without the focus related issues of the component in question, though within the Java Dimensions.
In the example below, the focus is on the JTextField first, so if you will Press CTRL + D, then the paintAction thingy attached to the CustomPanel will work, even though the focus lies with the JTextField.
Though if you will use the setMnemonic() method for JButton, then the JButton will gain focus and will perform it's own action associated with it, which is to draw Ovals. This you can see by Pressing ALT + C, to see the desired effect. Again to perform the drawing related thingy, both the components in question don't need the focus, but still they respond to the KeyStrokes.
Here is the example code :
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class SSCCE
{
private final int WIDTH = 500;
private final int HEIGHT = 500;
private CustomPanel customPanel;
private JButton circleButton;
private JTextField tfield;
private Random random;
private int mode;
private Action paintAction = new AbstractAction()
{
#Override
public void actionPerformed(ActionEvent ae)
{
mode = random.nextInt(3);
Color color = new Color(random.nextFloat(), random.nextFloat()
, random.nextFloat(), random.nextFloat());
customPanel.setValues(random.nextInt(WIDTH),
random.nextInt(HEIGHT), random.nextInt(WIDTH),
random.nextInt(HEIGHT), color, mode);
}
};
private ActionListener buttonAction = new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
Color color = new Color(random.nextFloat(), random.nextFloat()
, random.nextFloat(), random.nextFloat());
customPanel.setValues(random.nextInt(WIDTH),
random.nextInt(HEIGHT), random.nextInt(WIDTH),
random.nextInt(HEIGHT), color, 2);
}
};
public SSCCE()
{
random = new Random();
}
private void displayGUI()
{
JFrame frame = new JFrame("SSCCE");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setLayout(new BorderLayout(5, 5));
customPanel = new CustomPanel();
customPanel.getInputMap(
JComponent.WHEN_IN_FOCUSED_WINDOW).put(
KeyStroke.getKeyStroke(KeyEvent.VK_D
, InputEvent.CTRL_DOWN_MASK), "paintAction");
customPanel.getActionMap().put("paintAction", paintAction);
JPanel footerPanel = new JPanel();
circleButton = new JButton("Draw Circle");
circleButton.setMnemonic(KeyEvent.VK_C);
circleButton.addActionListener(buttonAction);
tfield = new JTextField(20);
tfield.setText("USELESS, just to get the focus for itself.");
tfield.requestFocusInWindow();
footerPanel.add(tfield);
footerPanel.add(circleButton);
contentPane.add(customPanel, BorderLayout.CENTER);
contentPane.add(footerPanel, BorderLayout.PAGE_END);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
new SSCCE().displayGUI();
}
});
}
}
class CustomPanel extends JPanel
{
private final int WIDTH = 500;
private final int HEIGHT = 500;
private int mode = 0;
private Color colorShape;
private int x = 0;
private int y = 0;
private int width = 0;
private int height = 0;
public void setValues(int x, int y, int w, int h, Color color, int mode)
{
this.x = x;
this.y = y;
this.width = w;
this.height = h;
this.colorShape = color;
this.mode = mode;
repaint();
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(WIDTH, HEIGHT));
}
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(colorShape);
if (mode == 1)
g.fillRect(x, y, width, height);
else if (mode == 2)
g.fillOval(x, y, width, height);
}
}
Related to mousePressed() thingy, #mKorbel, had presented the whole thingy as usual in a delightful manner.
And regarding your second question, seems like you yourself had done some homework on that. Seems like either using what you showed in your question is the workaround for catching Operating System related events and transfer that to your Java Application or Java Native Interface, I guess might also can work for this.

all JComponent has method dispatchEvent,
you can to redirect mouse & key event from one JComponent to the another
for JButton to use doClick() instead
for example
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class LostMouseEvent {
private JPanel panel1;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new LostMouseEvent();
}
});
}
public LostMouseEvent() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
panel1 = new JPanel() {
private static final long serialVersionUID = 1L;
#Override
public Dimension getPreferredSize() {
return new Dimension(600, 400);
}
};
JPanel panel2 = new JPanel() {
private static final long serialVersionUID = 1L;
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 300);
}
};
JScrollPane pane = new JScrollPane(panel2);
panel1.setBorder(BorderFactory.createLineBorder(Color.blue));
panel2.setBorder(BorderFactory.createLineBorder(Color.green));
panel1.setLayout(new CircleLayout());
panel1.add(pane);
frame.add(panel1);
MouseListener rml = new RealMouseListener();
panel1.addMouseListener(rml);
MouseListener fml = new FakeMouseListener();
panel2.addMouseListener(fml);
frame.pack();
frame.setVisible(true);
}
});
}
private class RealMouseListener extends MouseAdapter {
#Override
public void mousePressed(MouseEvent me) {
System.out.println(me);
Point point = me.getPoint();
System.out.println(me.getX());
System.out.println(me.getXOnScreen());
System.out.println(me.getY());
System.out.println(me.getYOnScreen());
}
}
private class FakeMouseListener extends MouseAdapter {
#Override
public void mousePressed(MouseEvent me) {
JPanel panel2 = (JPanel) me.getSource();
MouseEvent newMe = SwingUtilities.convertMouseEvent(panel2, me, panel1);
System.out.println(newMe.getX());
System.out.println(newMe.getXOnScreen());
System.out.println(newMe.getY());
System.out.println(newMe.getYOnScreen());
panel1.dispatchEvent(me);
}
}
}

IndexOutOfBounds tracking mouse with swing gui

I can't figure out why this simple program I wrote gets an IndexOutOfBounds exception when trying to update the coordinates of the mouse when the mouse leaves the tracking area (the white JPanel). I thought that the check on line 38 would take care of it. Any suggestions? Thanks!
import java.awt.*;
import javax.swing.JFrame;
public class MainFrame extends JFrame {
private static final long serialVersionUID = 1L;
Label coorLabel;
Panel coorPanel, content;
public MainFrame(String s){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container cont = getContentPane();
coorLabel = new Label("Mouse Coordinates: ");
coorPanel = new Panel();
coorPanel.setPreferredSize(new Dimension(400,400));
coorPanel.setBackground(Color.WHITE);
/**
content = new Panel();
content.add(coorPanel, BorderLayout.PAGE_START);
content.add(coorLabel, BorderLayout.PAGE_END);
**/
cont.add(coorPanel, BorderLayout.PAGE_START);
cont.add(coorLabel, BorderLayout.PAGE_END);
pack();
setVisible(true);
}
public void updateCoor(){
if(coorPanel.getMousePosition()!=null){
coorLabel.setText("Mouse Coordinates: "+getMousePosition().x+", "+getMousePosition().y);
coorLabel.repaint();
}
}
public static void main(String[]args){
MainFrame frame = new MainFrame("Coor App");
while(true){
frame.updateCoor();
}
}
}

Take a look at Concurrency in Swing tutorial. You are completely hogging initial
thread with a while(true) loop and updating user interface outside of Event Dispatch Thread.
See Introduction to Event Listeners to get familiar with Swing event model and How to Write a Mouse-Motion Listener in particular for mouse motion listener example.

Here is what you should do:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.*;
public class Stack extends JFrame implements MouseMotionListener{
int x;
int y;
JPanel p = new JPanel();
JPanel detectPanel = new JPanel();
JTextField t = new JTextField(10);
JLabel l = new JLabel("Position's inside of bordered panel: ");
public Stack(){
setLayout(new BorderLayout());
t.setEditable(false);
p.add(l);
p.add(t);
detectPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
add(p,BorderLayout.NORTH);
add(detectPanel,BorderLayout.CENTER);
detectPanel.addMouseMotionListener(this);
}
public static void main(String[] a){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
Stack s = new Stack();
s.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
s.setLocationByPlatform(true);
s.setPreferredSize(new Dimension(640,480));
s.pack();
s.setVisible(true);
}
});
}
public void mouseDragged(MouseEvent e) {
}
public void mouseMoved(MouseEvent e) {
x= e.getX();
y= e.getY();
t.setText(x+", "+y);
}
}

You check to see if coorPanel.getMousePosition() is not null, but then reference (this.)getMouseLocation(); try changing that to just say getMousePosition in the check, and add a print:
if( this.getMousePosition() != null ){
System.out.println(getMousePosition());
coorLabel.setText("Mouse Coordinates: "+getMousePosition().x+", "+getMousePosition().y);
coorLabel.repaint();
}