I created this java program and I wanted an output of which if int x and int y are above 100, it would draw a rectangle. But it doesn't. How can I make it work?Is there another line of code I need to add?
Here's my code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class GameSetup extends JPanel implements MouseMotionListener{
public static JFrame njf = new JFrame("Test");
public static int x, y;
public static void main(String[] args){
GameSetup gs = new GameSetup();
njf.add(gs);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
this.setBackground(Color.BLACK);
g.setColor(Color.GREEN);
g.fillRect(150, 75, 200, 100);
g.setColor(Color.ORANGE);
g.drawString("Play", 239, 123);
njf.addMouseListener(new MouseAdapter() {
public void mouseMoved(MouseEvent e) {
x = e.getX();
y = e.getY();
}
});
if(x > 100 && y > 100){
g.drawRect(10, 10, 100, 100);
}
}
public GameSetup(){
njf.setSize(500,500);
njf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
njf.setResizable(false);
njf.setLocationRelativeTo(null);
njf.setVisible(true);
}
#Override
public void mouseDragged(MouseEvent arg0) {
}
#Override
public void mouseMoved(MouseEvent e) {
}
}
Okay, there are several things wrong with the code that you included above.
The first that stood out to me was the way that you are adding the mouse action listener to frame. There are multiple things that are wrong with this.
First of all, you are doing this in the paintComponent method, which, if it works, is still considered to be bad practice because the paintComponent method may be called multiple times. Do that, as pointed out by the comments, in the constructor of the panel.
The second is that you are adding the mouse listener to the frame, not the panel, which doesn't work because the panel is "above" the frame, so the mouse event will only be recognized within the panel. Your best bet here is to add a MouseMotionListener directly to the panel itself.
The third is that you are implementing the MouseMotionListenerinterface in the GameSetup class, but never actually doing anything with this implementation. So what I did was that I got rid of the inner class, and just had the panel be its own MouseMotionListnener
The second thing that is wrong with the code is that the paintComponent method is only called at certain points in time (see this). That means that even though the mouse might have moved within the zone, your paintComponent method isn't being called to update the screen accordingly. For this, you need to call the repaint method for your panel.
The third is that you didn't set a size for your panel, and the default one is 0x0, so you need to set a size of your panel (which should be the same as the frame itself) (if you want to keep the default layout).
All of that being said, here is your code that I fixed up. I added a variable called enteredZone to keep track of if the mouse had previously entered the zone, so that the rectangle would stay up even if the mouse left the zone after entering it (its your choice if you want to keep it). Note that there are other things with this code that might be considered bad practice, but this is enough to get you started:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class GameSetup extends JPanel implements MouseMotionListener {
public static JFrame njf = new JFrame("Test");
public static int x = 0, y = 0;
public static boolean enteredZone = false;
public static void main(String[] args) {
GameSetup gs = new GameSetup();
gs.addMouseMotionListener(gs);
njf.add(gs);
njf.setVisible(true);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
this.setBackground(Color.BLACK);
g.setColor(Color.GREEN);
g.fillRect(150, 75, 200, 100);
g.setColor(Color.ORANGE);
g.drawString("Play", 239, 123);
if (x > 100 && y > 100 || enteredZone){
g.drawRect(10, 10, 100, 100);
enteredZone = true;
}
}
public GameSetup() {
super();
setSize(500, 500);
njf.setSize(500,500);
njf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
njf.setResizable(false);
njf.setLocationRelativeTo(null);
}
#Override
public void mouseDragged(MouseEvent arg0) {
}
#Override
public void mouseMoved(MouseEvent e) {
x = e.getX();
y = e.getY();
if (x > 100 && y > 100) repaint();
}
}
Related
Where to place JOptionPaneShowInputDialog code?
Where to place JOptionPaneShowInputDialog code?Where to place JOptionPaneShowInputDialog code?
Where to place JOptionPaneShowInputDialog code?
Where to place JOptionPaneShowInputDialog code?
I would like to add a JoptionPaneShowInputDialog()(not in code yet) inside the code herebelow.
I can do, but I cannot make the dialog appearing in the black panel,before the recursion.
The dialog appears after the drawing...
public class FractalTree extends JPanel implements ActionListener
{
int x1=350;
int y1=600;
int angle=-90;
int depth=11;
int k=10;
JLabel label_1;
private void drawTree(Graphics g, int x1, int y1, double angle, int depth, int k)
{
if(depth==11)
g.setColor(Color.GRAY);
g.fillRect(100, 600, 1160, 10);
g.setColor(Color.white);
if (depth == 0) return;
((Graphics2D) g).setStroke(new BasicStroke((float) (k*0.9)));
int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 11*Math.random()+1);
int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 11*Math.random()+1);
if(depth<3)
{
g.setColor(Color.green);
}
g.drawLine(x1, y1, x2, y2);
drawTree(g, x2, y2, angle - 19, depth-1,k-1);
drawTree(g, x2, y2, angle + 19, depth-1,k-1);
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.white);
drawTree(g,x1,y1,angle,depth,k);
drawTree(g,x1+600,y1,angle,depth,k);
}
public FractalTree()
{
this.setBackground(Color.black);
}
public static void gui()
{
JFrame f=new JFrame("fractal tree");
JLabel label_1=new JLabel("<html>RANDOM TREE<br><center>FRACTAL");
label_1.setForeground(Color.red);
Font font = new Font("Courier", Font.BOLD,25);
label_1.setFont(font);
FractalTree ft=new FractalTree();
f.getContentPane().add(ft);
f.setSize(1500, 1000);
JButton button = new JButton("Close Me");
button.addActionListener(ft);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ft.add(label_1);
ft.add(button);
f.setUndecorated(true);
f.setVisible(true);
}
public static void main(String[] args)
{
gui();
}
#Override
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
}
May I ask some help?
Thanks
The question and intent are some what unclear. What is the purpose of the dialog?
I assume you want to gather some information which can then be passed to the FractalTree to change it's rendering
The question and intent are some what unclear. What is the purpose of the dialog?
I assume you want to gather some information which can then be passed to the FractalTree to change it's rendering, in that case you probably need to put the dialog before the creation of the FractalTree
public static void gui()
{
// You can put the dialog here...
JFrame f=new JFrame("fractal tree");
//...
If you want to change the properties FractalTree after its been displayed, then you probably need to use a JButton and a ActionListener and place the dialog in there ... or provide a second view to gather the properties directly
In fact, the purpose of the dialog box is to ask the recursion level. If I place it like you propose, its ok, but the dialog box appears alone, not in the black panel, and I would like that it appears in the panel...
Let's just be clear, SO is NOT a tutorial or mentoring site. Your problem isn't a technical problem, but an experience one. You should spend more time reading through tutorials like Creating a GUI With Swing and trying things. This is how you will become a better developer and learn to solve your own problems.
Based on your feedback, JOptionPane isn't what you need.
Instead, you need to take a slightly different approach and supply your own input component.
First, you need to change FractalTree so that you can modify the depth property more easily (and set the initial depth to 0 so it will stop drawing)
public class FractalTree extends JPanel implements ActionListener {
private int depth = 0; // set to 0 to stop it from rendering
public void setDepth(int depth) {
this.depth = depth;
repaint();
}
public int getDepth() {
return depth;
}
Next, you need to create your own input component, which can take input from the user and update the tree
public class InputPane extends JPanel {
private FractalTree fractalTree;
private JTextField depthField;
public InputPane(FractalTree fractalTree) {
this.fractalTree = fractalTree;
depthField = new JTextField(10);
depthField.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
String text = depthField.getText().trim();
try {
int value = Integer.parseInt(text);
fractalTree.setDepth(value);
} catch (NumberFormatException exp) {
JOptionPane.showMessageDialog(InputPane.this, text + " is not a valid numerical value");
}
}
});
}
}
Then you want to create a new entry point that can combine the two...
import java.awt.EventQueue;
import javax.swing.JFrame;
public class Main {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
FractalTree tree = new FractalTree();
InputPane input = new InputPane(tree);
JFrame frame = new JFrame();
frame.add(tree);
frame.add(input, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
Yes, this is going to produce a small window, because FractalTree doesn't define any sizing hints, which can be solved by overriding it's getPreferredSize method and returning a more suitable size.
This is going to put you own a "better path", there are still issues you're going to have to solve, because doing it all for you won't help you
I was suggested not to use sleep for pausing purpose and instead use swing timer but still its not working.The animation i want to achieve is a ball travelling from the top left corner diagonally towards the bottom.
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class Show_starter {
int x, y;
JFrame window = new JFrame("Graphic_show");
Graphic_panel jp = new Graphic_panel();
public static void main(String[] args) {
Show_starter start = new Show_starter();
start.go();
}
private void go() {
window.getContentPane().add(BorderLayout.CENTER, jp);
window.setSize(600,800);
window.setVisible(true);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
class Graphic_panel extends JPanel {
public void paintComponent(Graphics g) {
for ( int i = 0; i < 100; ++i) {
g.setColor(Color.white);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setColor(Color.green);
g.fillOval(x, y, 40, 40);
x++;
y++;
try {
Timer tmr = new Timer(1000, new TimerListener()); //This fires an event after every 1 sec after it has started by start().
//But The ball travels too much fast and stops at a point and again travels very fast.
tmr.serRepeats(false); // even this is not working.
tmr.start();
//should i use repaint here or in Listener for this timer?
} catch (Exception e){}
}
}
class TimerListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
jp.repaint();
}
}
}
}
The behaviour it is showing is very odd ball first goes at very high speed and stops momentarily at a point and again moves at same speed.
I have also tried to change the time for timer event to fire but the same thing happens.
Even inside loop where I have started timer the follow function call is not working
setRepeats(false);
don't create new timers always one timer is enough .decrees timing interval bit more .1 second is too slow for a animation.you don't need a loop and don't increment x and y inside paintcomponet() method because this method get called for some reason for example when you resize,minimize,maximize.
the unexpected behavior is due to your loop and creating new timers(). for example in x y start at zero but in first second x y increased to 100,100 in next paint you see them in a 100,100 position .that's look like quick move and then stop ...
example code (edited)
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Show_starter {
private Timer tmr;
int x, y;
JFrame window = new JFrame("Graphic_show");
Graphic_panel jp = new Graphic_panel();
public static void main(String[] args) {
Show_starter start = new Show_starter();
start.go();
}
private void go() {
window.getContentPane().add(BorderLayout.CENTER, jp);
window.setSize(600, 800);
window.setVisible(true);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
tmr = new Timer(10, new ActionListener() { // time gap in millisecond
#Override
public void actionPerformed(ActionEvent ae) {
jp.increse();
jp.repaint();
}
});
tmr.start();
}
class Graphic_panel extends JPanel {
public void increse() {
x++;
y++;
if (x > 100) { // stop animation at x>100
tmr.stop();
}
}
public void paintComponent(Graphics g) {
g.setColor(Color.white);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setColor(Color.green);
g.fillOval(x, y, 40, 40);
}
}
}
output (smoother than that)
Firstly you should not use a loop inside paint component.
public void paintComponent(Graphics g){
g.setColor(Color.white);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setColor(Color.green);
g.fillOval(x, y, 40, 40);
}
Just draw it and make x and y public in the class so that you can easily access from outside
Now run a runnable (consult invokelater and swingUtilities) or create a new Thread
inside public void run() do whatever animations you want to do . You can use a loop but add Thread.sleep(//in miliseconds) and repaint() in each iteration .
note : you need to change the x and y and repaint() so that it is drawn in a new position. And the sleep() is needed to slow down the execution otherwise it can't be visible to viewer.
I want to develop a Java Applet which shows visualization of Sorting. So I have written code like this...
public class SortNumbersGUI extends JApplet {
private static final long serialVersionUID = 1L;
List<Integer> randomList;
JLabel numberLabel;
JButton sortButton;
#Override
public void init() {
randomList = MyRandom.myRandom();
setSize(400, 400);
setLayout(new FlowLayout());
sortButton = new JButton("Sort");
sortButton.setBounds(50, 0, 50, 10);
sortButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Collections.sort(randomList);
removeAll();
repaint();
}
});
this.add(sortButton);
super.init();
}
#Override
public void paint(Graphics g) {
int y = 20;
for (Integer i : randomList) {
g.drawString(i.toString(), 0, y + 10);
g.fillRect(20, y, (i * 10) / 10, 5);
y = y + 20;
}
}
}
But, I am facing two problems here..
Sort button, which is JButton is not always visible. When i am placing mouse cursor over that sort button place then only it is appearing.
The results are overriding when I am calling repaint() method. As the bellow image
Result Image (As I don't have reputation I am pasting the image link.)
Please help me to solve this problem.
Thank you in Advance.
#Override
public void paint(Graphics g) {
// ..
Should be:
#Override
public void paint(Graphics g) {
super.paint(g); // paints **BG**, border etc.
// ..
Your problem is that you are overridding paint instead of paintComponent, and also you are not calling super.paint/Component (also a good practice, though possibly not 100% necessary here).
Because of how you've overridden paint(), you button is not getting automatically painted when the JApplet is painted
Hey Everyone I am trying to create a somewhat dynamic program in which you can add shapes or images to a JPanel and then select and move the shapes after you have added them. The problem is that when I click on the specific JComponent nothing happens. In fact clicking on any of the components I have created to test the project returns false for all JComponents. However it seems that if I click inside the bounds of my JComponent in the top left corner I will get returned true for all JComponents, ie click in the area bounded by (0,0,50,68).
The idea is that if I click one of the JComponents it will set that specific JComponent to be movable however I cannot get past the part of actually selecting a specific JComponent.
Here is a basic SSCE that I built to recreate the problem:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class SSCE1 extends JPanel {
private ArrayList<Shape> shapeList = new ArrayList<Shape>();
SSCE1() {
setLayout(null);
/* Debug Stuff */
System.out.println("Debug:");
/* Add The First Shape To The List */
shapeList.add(0, new Shape(100, 100));
add(shapeList.get(0));
shapeList.add(1, new Shape(610, 0));
add(shapeList.get(1));
shapeList.add(2, new Shape(500, 900));
add(shapeList.get(2));
addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
for (Shape shape : shapeList) {
if (shape.contains(e.getPoint())) {
System.out.println("Hello");
} else {
System.out.println("Goodbye");
}
}
}
});
}
}
class Shape extends JComponent {
int xLocation, yLocation, xBounds1, yBounds1;
Shape(int xLocation, int yLocation) {
this.xLocation = xLocation;
this.yLocation = yLocation;
this.xBounds1 = 50;
this.yBounds1 = 68;
setBounds(xLocation, yLocation, xBounds1, yBounds1);
setLocation(xLocation, yLocation);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.blue);
g.fillRect(0, 0, 100, 100);
}
}
class Run {
public static void main(String[] args) {
JFrame main = new JFrame();
SSCE1 p1 = new SSCE1();
main.setSize(new Dimension(1000, 1000));
main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
main.setLocation(new Point(0, 0));
main.setVisible(true);
main.add(p1);
}
}
Basically, the problem is, Shape is expecting any mouse coordinates you pass it to be defined within the context of the Shape. That is, the top, left corner of Shape is always 0x0
The mouse point you are processing is within the context of the parent container, therefore, unless Shape is positioned at 0x0 within the parent container, Shape will never contain the mouse point.
You need to translate the mouse point to the context of the Shape before checking it
For example...
addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
for (Shape shape : shapeList) {
Point shapePoint = SwingUtilities.convertPoint(e.getComponent(), e.getPoint(), shape);
if (shape.contains(shapePoint) {
System.out.println("Hello");
} else {
System.out.println("Goodbye");
}
}
}
});
Use next mouseListener it works:
addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
for (Shape shape : shapeList) {
Point convertPoint = SwingUtilities.convertPoint(SSCE1.this, e.getPoint(), shape);
if (shape.contains(convertPoint)) {
System.out.println("Hello");
} else {
System.out.println("Goodbye");
}
}
}
});
The reason is next according docs in contains method the point's x and y coordinates are defined to be relative to the coordinate system of this component. because of that works for (0,0,50,68). All what you need convert point from JPanel to Shape with help of SwingUtilities.convertPoint(...)
I am a new in java, and I need to implement a paint application, and I'm kinda stuck at the beggining, I managed to draw lines to a JPanel which I added to a JFrame, but each line drawn resets the entire drawing, and in the draw area remains only the last line drawn. I hope I made myself understood, here his the code:
class Shapes extends JFrame {
public JFrame mf = new JFrame("Paint");
DrawArea da = new DrawArea();
JToggleButton lineButton = new JToggleButton(new ImageIcon("line.gif"));
JToggleButton brushButton = new JToggleButton();
JToggleButton pencilButton = new JToggleButton();
JToggleButton eraserButton = new JToggleButton(new ImageIcon("eraser_icon.png"));
JToggleButton rectangleButton = new JToggleButton();
JToggleButton ovalButton = new JToggleButton();
Shapes() {
da.setBounds(120, 50, 500, 350);
da.setBackground(Color.YELLOW);
mf.setSize(700, 500);
mf.setLayout(null);
lineButton.setBounds(0, 50, 40, 40);
brushButton.setBounds(40, 50, 40, 40);
eraserButton.setBounds(0, 90, 40, 40);
pencilButton.setBounds(40, 90, 40, 40);
rectangleButton.setBounds(0, 130, 40, 40);
ovalButton.setBounds(40, 130, 40, 40);
mf.setBackground(Color.red);
mf.add(lineButton);
mf.add(brushButton);
mf.add(pencilButton);
mf.add(eraserButton);
mf.add(rectangleButton);
mf.add(ovalButton);
mf.add(da);
mf.show();
mf.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
mf.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
System.out.println("x:" + e.getX() + "y:" + e.getY() + "\n" + "x2:" + e.getXOnScreen() + "y2:" + e.getYOnScreen());
}
});
eraserButton.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e)
{
eraserButton.setSelectedIcon(new ImageIcon("eraser_icon_selected.png"));
}
});
lineButton.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e)
{
lineButton.setSelectedIcon(new ImageIcon("line_selected.png"));
}
});
da.addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
da.setXvalue(e.getX());
da.setYvalue(e.getY());
}
public void mouseReleased(MouseEvent e) {
da.setX2value(e.getX());
da.setY2value(e.getY());
da.repaint();
}
});
da.addMouseMotionListener(new MouseAdapter() {
public void mouseDragged(MouseEvent e) {
da.repaint();
da.setX2value(e.getX());
da.setY2value(e.getY());
}
});
}
}
public class DrawArea extends JPanel {
int x1value,y1value,x2value,y2value;
public int getX2value() {
return x2value;
}
public void setX2value(int x2value) {
this.x2value = x2value;
}
public int getY2value() {
return y2value;
}
public void setY2value(int y2value) {
this.y2value = y2value;
}
public JPanel dra=new JPanel();
public int getXvalue() {
return x1value;
}
public void setXvalue(int xvalue) {
this.x1value = xvalue;
}
public int getYvalue() {
return y1value;
}
public void setYvalue(int yvalue) {
this.y1value = yvalue;
}
public void paint(Graphics g)
{
super.paint(g);
g.setColor(Color.red);
g.drawLine(getXvalue(),getYvalue(),getX2value(),getY2value());
}
}
class Paint extends JPanel
{
public static void main(String args[])
{
Shapes s=new Shapes();
}
}
See Custom Painting Approaches for two solutions. The examples draw rectangles, but the concept is the same for lines.
Override paintComponent(), not paint(). Read this tutorial. When a panel needs to be redrawn, you call that panels repaint() method.
Paint is called by the window manager any time it considers that area 'unfresh'. If you do it the way you're doing it right now, you will draw the last line drawn every time.
The proper way to do this would be to make a BufferedImage in memory and draw on that. Then, in the paint method, blit the BufferedImage onto the surface. This also makes scrolling and zooming quite easy to do.
Whenever you perform such an action, invalidate the surface so that the window manager will call the paint method for you.
You are only storing one line, and overwriting it each time, so when the component is repainted, the old one is erased and the new one is redrawn.
The expectation of paintComponent and the like is that your implementation will draw EVERY graphical element that you want to appear, each time it is called.
Instead of storing x1, y1, x2, y2, you should make a LineSegment class or similar that stores those values. Then, when you paint, you call g.drawLine() for each LineSegment object that you've stored (presumably in an ArrayList or similar). Then, when the component is redrawn, all of your line segments should appear on the screen.
A little bit off topic, but I had a few uncomfortable minutes cause I used update() instead of repaint(). I advice to everyone working with SWING to spend some time checking which methods should handled as thread safe and which ones has to be on EDT (Event Dispatcher Thread) to make sure you won't get some unexpected errors.
This is a good article about this.
Also, at the beginning think through if you want to have an undo/redo system in your app...
If so, than how many steps you want to allow being withdrawn. If you want to allow this feature than you cannot just draw and forget about what you draw last time.
Also it would be not memory efficient to store all the images you draw so far. I'm not an expert and I'm not saying this is the best practice but I would go this way:
I would make two lists.
One of them would store the applied drawing actions,
the other would contain the withdrawn drawing actions.
Drawing action would be an interface and some class would implement it for each specific kind of drawing action (LineDrawAction, CirceDrawAction...).
When you draw a new line or whatever you would empty the withdrawn actions list and add it to the applied action list. When someone undo the last action, than I would just remove the last drawing actions from the applied list and would add to the withdrawn list (etc...). Depending on if you want to allow only the last x action to be undone when a list reaches this x limit I would remove the first drawing action from the list or queue and would finally draw to the picture - this means permanent drawing and this cannot be undone.
I hope it's clear and useful even if not a direct answer to your question.