I'm using the getX() and getY() methods in the MouseListener class to get the location of the panel, but it's getting the location of the frame instead, and that includes the top of the title bar and the sides, so it's not getting the location that I want. I also have the:
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
method in my paint class to override the frame so when you paint in graphics, and set the paint location of x, and y, it sets it to the panel location, and not the frame location, but I don't know how to make it so that the MouseListener class does the same. Please help. Thanks.
Code for the MouseListener class:
package events;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Events implements ActionListener, MouseListener, MouseMotionListener {
static Events events = new Events();
int x;
int y;
public void actionPerformed(ActionEvent e) {
}
public void mousePressed(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mouseClicked(MouseEvent e) {
x = e.getX();
y = e.getY();
System.out.println("X:" + x + " " + "Y:" + y);
}
public void mouseMoved(MouseEvent e) {
}
public void mouseDragged(MouseEvent e) {
}
}
Nevermind. I can just call the panel name for the panel x, and y locations. But thanks anyways.
x = P.g.getX();
y = P.g.getY()
Related
i am writing a program that when the mouse is clicked, a circle will be drawn. The below code i've wrote so far.
import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.event.*;
import java.awt.geom.*;
public class test extends JFrame implements ActionListener, MouseListener {
Shape circle = new Ellipse2D.Float(10, 10, 10, 10);
public test () {
setSize(250,150);
addMouseListener(this);
}
public static void main(String[] args) {
//TODO code application logic here
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
test frame = new test();
frame.setVisible(true);
}
});
}
public void actionPerformed(ActionEvent ae) {
}
public void drawCircle(int x, int y) {
Graphics g = this.getGraphics();
g.drawOval(x, y, x, y);
g.setColor(Color.BLACK);
g.fillOval(x, y, 2, 2);
}
public void mouseClicked(MouseEvent e) {
drawCircle(e.getX(), e.getY());
repaint();
}
public void mouseExited(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
}
The code is a 400X400 jframe, when clicked open display a circle at a half seconds, The problem is that, when i release the mouse, the circle disappear. why?
Change your mouseClick(...) to:
int x, y;
public void mouseClicked(MouseEvent e) {
x = e.getX();
y = e.getY();
repaint();
}
Override paint(...):
#Override
public void paint(Graphics g) {
drawCircle(x, y);
}
When you call repaint(), the component gets painted again from scratch. You're circle is wiped away. You will want to override paintComponent(Graphics) which is called every time the component is painted.
I'm experimenting on a GUI that I programmed and I don't understand how I can fix my problem:
My GUI contains a jPanel that on receiving a mouseclick, paints a point with filloval command.
private void myPnlMousePressed(java.awt.event.MouseEvent evt) {
changed = true;
p.x = evt.getX();
p.y = evt.getY();
drewPoints(p.x, p.y);
}
private void drewPoints (int x, int y) {
if (gf == null) {
gf = (Graphics)myPnl.getGraphics();
}
myPointsList.add(new Point(x, y));
gf.fillOval(x, y, 5, 5);
xVal.setText("X = " + x);
yVal.setText("Y = " + y);
}
everything works fine but when I want to open an XML file that I created to save all the points it doesn't work.
The problem is that when I use the repaint method on the jPanel after choosing a file, all the points loads fine but the panel can't draw the points.
If I put the repaint method in the open button listener (before the choosing file) it works, but then if the user cancels the open option so the panel stays blank and I don't want to draw the points again.
I think it happens because the repaint process is not finished.
All the points added to a private List.
private void OpenFile() {
try {
File thisFile;
JFileChooser of = new JFileChooser();
int option = of.showOpenDialog(of);
if (option == JFileChooser.APPROVE_OPTION){
thisFileName = of.getSelectedFile().getPath();
thisFile = new File(thisFileName);
if (!of.getSelectedFile().getName().endsWith(".xml")) {
String error = "Error, You didn't select XML file";
JOptionPane.showMessageDialog(this, error, "Wrong type of file", JOptionPane.INFORMATION_MESSAGE);
return;
}
myPnl.repaint();
myPointsList.clear();
....
....
....
for (int i = 0; i < pointsList.getLength(); i++) {
Element point = (Element) pointsList.item(i);
p.x = Integer.parseInt(point.getElementsByTagName("X").item(0).getTextContent());
p.y = Integer.parseInt(point.getElementsByTagName("Y").item(0).getTextContent());
drewPoints(p.x, p.y);
}
....
how can I make it work??
Don't use gf = (Graphics)myPnl.getGraphics();, this is not how painting in Swing works. The getGraphics method can return null and is nothing more then a snap shot of the last paint cycle, any thing you paint to it will be erased on the next paint cycle (repaint).
Instead, override the JPanels paintComponent and put all you painting logic there. There is an expectation that when called, you are expected to fully re-paint the current state of the component.
See Painting in AWT and Swing and Performing Custom Painting for more details about how painting works in Swing
You have to use the repaint() and override the paint() method:
class MyPanel extends JPanel implements MouseListener
{
private int x;
private int y;
public MyPanel() {
super();
addMouseListener(this);
}
#Override public void mouseEntered(MouseEvent e) { }
#Override public void mouseExited(MouseEvent e) { }
#Override public void mouseClicked(MouseEvent e) { }
#Override public void mousePressed(MouseEvent e) { }
#Override public void mouseReleased(MouseEvent e) {
x = e.getX();
y = e.getY();
repaint();
}
#Override public void paint(Graphics g) {
super.paint(g);
g.fillOval(x, y, 10, 10);
}
}
If you want to draw all points, don't use x and y but a list of points:
class MyPanel extends JPanel implements MouseListener
{
private ArrayList<Point> points = new ArrayList<>();
public MyPanel() {
super();
addMouseListener(this);
}
#Override public void mouseEntered(MouseEvent e) { }
#Override public void mouseExited(MouseEvent e) { }
#Override public void mouseClicked(MouseEvent e) { }
#Override public void mousePressed(MouseEvent e) { }
#Override public void mouseReleased(MouseEvent e) {
points.add(new Point(e.getX(), e.getY()));
repaint();
}
#Override public void paint(Graphics g) {
super.paint(g);
for (Point p : points)
g.fillOval(p.getX(), p.getY(), 10, 10);
}
}
where:
class Point
{
private int x;
private int y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
Then use it:
public static void main(String[] args) {
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.setLocationRelativeTo(null);
MyPanel myPanel = new MyPanel();
frame.add(myPanel);
frame.setVisible(true);
}
I'm trying to create an applet that draws a circle (defined as an object) to the screen then this circle can be dragged across the screen using the mouse. So far when the mouse is pressed the object is drawn and can be dragged, but what I want it to do is draw the object when the applet is started then allow the user to click on the object and drag it. Any help or clues would be much appreciated. here is the code:
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
public class sheepDog extends Applet implements ActionListener, MouseListener, MouseMotionListener
{
manAndDog dog;
int xposR;
int yposR;
public void init()
{
addMouseListener(this);
addMouseMotionListener(this);
}
public void paint(Graphics g)
{
dog.display(g);
}
public void actionPerformed(ActionEvent ev)
{}
public void mousePressed(MouseEvent e)
{
}
public void mouseReleased(MouseEvent e)
{
}
public void mouseEntered(MouseEvent e)
{}
public void mouseExited(MouseEvent e)
{}
public void mouseMoved(MouseEvent e)
{
}
public void mouseClicked(MouseEvent e)
{}
public void mouseDragged(MouseEvent e)
{
dog = new manAndDog(xposR, yposR);
xposR = e.getX();
yposR = e.getY();
repaint();
}
}
class manAndDog implements MouseListener, MouseMotionListener
{
int xpos;
int ypos;
int circleWidth = 30;
int circleHeight = 30;
Boolean mouseClick;
public manAndDog(int x, int y)
{
xpos = x;
ypos = y;
mouseClick = true;
if (!mouseClick){
xpos = 50;
ypos = 50;
}
}
public void display(Graphics g)
{
g.setColor(Color.blue);
g.fillOval(xpos, ypos, circleWidth, circleHeight);
}
public void mousePressed(MouseEvent e)
{
mouseClick = true;
}
public void mouseReleased(MouseEvent e)
{
}
public void mouseEntered(MouseEvent e)
{}
public void mouseExited(MouseEvent e)
{}
public void mouseMoved(MouseEvent e)
{}
public void mouseClicked(MouseEvent e)
{}
public void mouseDragged(MouseEvent e)
{
if (mouseClick){
xpos = e.getX();
ypos = e.getY();
}
}
}
Thanks
In the start method of your applet, assign a location for the manAndDog object and call repaint
Reimeus is more correct, the init method is a better place to initalise the manAndDog.
Hope you don't mind some feedback ;)
You should be calling super.paint(g) in your paint method. In fact, I'd encourage you to use JApplet and override paintComponent, but that's just me
I don't see the need to continuously recreate the manAndDog object.
For example. If you added a method setLocation, you could simply call 'setLocation` when the mouse is dragged.
public void mouseDragged(MouseEvent e) {
dog.setLocation(xposR, yposR);
xposR = e.getX();
yposR = e.getY();
repaint();
}
This is more efficient as it's not continuously creating short lived objects. It also means you can do more with the manAndDog object, such as apply animation. IMHO
The simplest way is to create the ManAndDog object in your init() method, something like:
dog = new ManAndDog(0, 0);
Trying to work with basic swing on Java keeps giving me issues.
When the JFrame is created by the runtime, none of the components are drawn initially, you have to resize the window to invoke paint() apparently? Is there a simple fix to this that I'm missing?
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class LabTen extends JFrame{
int x, y;
public LabTen(){
this.setSize(200,200);
this.setVisible(true);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.getContentPane().add(new Board()); //do this in the constructor
}
public static void main(String[] args){
LabTen one = new LabTen();
one.repaint();
}
}
//mouseListener has more things when we're going in and out so you should have it too
//write on the component or pannel, not the frame
class Board extends JComponent implements MouseListener, MouseMotionListener{
int mouseX, mouseY;
public Board(){
addMouseListener(this);
addMouseMotionListener(this);
}
public void mouseMoved(MouseEvent e){
this.mouseX = e.getX();
this.mouseY = e.getY();
this.repaint();
}
public void mouseDragged(MouseEvent e){
//do nothing...
}
public void mouseClicked(MouseEvent e){
}
public void mouseEntered(MouseEvent e){
}
public void mouseExited(MouseEvent e){
}
public void mousePressed(MouseEvent e){
}
public void mouseReleased(MouseEvent e){
}
public void paintComponent(Graphics g){
//g.drawString("(" + this.mouseX + ", " + this.mouseY + ")", this.mouseX,this.mouseY);
//this uses the default way
// g.drawLine(this.getWidth()/2, this.getHeight()/2, this.mouseX, this.mouseY);
double distance = Math.sqrt(Math.pow(this.mouseX - this.getWidth()/2, 2) + Math.pow(this.mouseY - this.getHeight()/2, 2));
int centerX = this.getWidth()/2;
int centerY = this.getHeight()/2;
for(int i = 0; i < 20; i++){
double distanceX =
g.drawLine(centerX, centerY, (centerX))
}
}
}
You are doing it completely the wrong order. Do it this way:
Add the component
this.add(new Board());
Set the preferred size
this.setPreferredSize(new Dimension(200, 200));
Pack the frame
this.pack();
Set the frame visible.
this.setVisible(true);
Of course, this is your JFrame.
Once you're done setting up your JFrame, you should call jFrame.pack() and jFrame.setVisible(true).
All components need to be added to the container before it's realized.
I searched the web for examples of draggable Swing components,
but I found either incomplete or non-working examples.
What I need is a Swing component that can be dragged by the mouse
inside an other component. While being dragged, it should already
change its position, not just 'jump' to its destination.
I would appreciate examples which work without non-standard APIs.
Thank you.
I propose a simple, but well-working solution, found out by myself ;)
What do I do?
When mouse is pressed, I record the cursor's position on screen, and
the component's position.
When mouse is dragged, I calculate the difference between new and
old cursor's position on screen, and move the
component by this difference.
Tested with latest JDK 6 unter Linux (OpenSuse, KDE3),
but hey, it's Java Swing, should work equally everywhere.
Here goes the code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
public class MyDraggableComponent
extends JComponent {
private volatile int screenX = 0;
private volatile int screenY = 0;
private volatile int myX = 0;
private volatile int myY = 0;
public MyDraggableComponent() {
setBorder(new LineBorder(Color.BLUE, 3));
setBackground(Color.WHITE);
setBounds(0, 0, 100, 100);
setOpaque(false);
addMouseListener(new MouseListener() {
#Override
public void mouseClicked(MouseEvent e) { }
#Override
public void mousePressed(MouseEvent e) {
screenX = e.getXOnScreen();
screenY = e.getYOnScreen();
myX = getX();
myY = getY();
}
#Override
public void mouseReleased(MouseEvent e) { }
#Override
public void mouseEntered(MouseEvent e) { }
#Override
public void mouseExited(MouseEvent e) { }
});
addMouseMotionListener(new MouseMotionListener() {
#Override
public void mouseDragged(MouseEvent e) {
int deltaX = e.getXOnScreen() - screenX;
int deltaY = e.getYOnScreen() - screenY;
setLocation(myX + deltaX, myY + deltaY);
}
#Override
public void mouseMoved(MouseEvent e) { }
});
}
}
public class Main {
public static void main(String[] args) {
JFrame f = new JFrame("Swing Hello World");
// by doing this, we prevent Swing from resizing
// our nice component
f.setLayout(null);
MyDraggableComponent mc = new MyDraggableComponent();
f.add(mc);
f.setSize(500, 500);
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setVisible(true);
}
}
Also, I found out that one could create an JInternalFrame inside an JFrame,
but the problem is: you get always an annoying window title bar.
To disable the title bar, sadly, a dirty workaround is necessary:
public class MyDraggableComponent extends JInternalFrame {
public MyDraggableComponent() {
InternalFrameUI thisUI = getUI();
if (thisUI instanceof BasicInternalFrameUI) {
((BasicInternalFrameUI) thisUI).setNorthPane(null);
}
}
I really miss a method like "someInternalFrame.setWindowTitleBar(false)"...
:'(