I insert an image to a JPanel. I write this code.
public void paint(Graphics g)
{
img1=getToolkit().getImage("/Users/Boaz/Desktop/Piece.png");
g.drawImage(img1, 200, 200,null);
}
I want to add an action listener to that picture, but it does not have an addActionListener() method. How can I do that without putting the image in a button or label?
There are a few options.
Use a MouseListener directly in the JPanel
A simple but dirty way would be to add an MouseListener directly to the JPanel in which you overrode the paintComponent method, and implement a mouseClicked method which checks if the region where the image exists has been clicked.
An example would be something along the line of:
class ImageShowingPanel extends JPanel {
// The image to display
private Image img;
// The MouseListener that handles the click, etc.
private MouseListener listener = new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
// Do what should be done when the image is clicked.
// You'll need to implement some checks to see that the region where
// the click occurred is within the bounds of the `img`
}
}
// Instantiate the panel and perform initialization
ImageShowingPanel() {
addMouseListener(listener);
img = ... // Load the image.
}
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, null);
}
}
Note: An ActionListener can't be added to a JPanel, as a JPanel itself does not lend itself to create what is considered to be "actions".
Create a JComponent to display the image, and add a MouseListener
A better way would be to make a new subclass of JComponent whose sole purpose is to display the image. The JComponent should size itself to the size of the image, so that a click to any part of the JComponent could be considered a click on the image. Again, create a MouseListener in the JComponent in order to capture the click.
class ImageShowingComponent extends JComponent {
// The image to display
private Image img;
// The MouseListener that handles the click, etc.
private MouseListener listener = new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
// Do what should be done when the image is clicked.
}
}
// Instantiate the panel and perform initialization
ImageShowingComponent() {
addMouseListener(listener);
img = ... // Load the image.
}
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, null);
}
// This method override will tell the LayoutManager how large this component
// should be. We'll want to make this component the same size as the `img`.
public Dimension getPreferredSize() {
return new Dimension(img.getWidth(), img.getHeight());
}
}
The easiest way is to put the image into a JLabel. When you use the program, it appears to just be the image, you can't tell its in a JLabel. Then just add a MouseListener to the JLabel.
Related
The situation here is the following: I have a JFrame, in which I store a list of images. When the right-key is pressed, I display the next image in this fullscreen JFrame. I want a Exit JButton in the upper right corner of the screen, which is the problem. To achieve that, I create a new JPanel everytime the image is changed, remove the old JPanel from the frame, and add the JButton to the new JPanel. The issue is the following: when I start the program, the JButton is in the middle of the JFrame. Once I load the next Image by pressing the right key the JButton is on the right position. However, workarounds like calling the method to display the next Image fail. Even if I set the JButton invisible until the right key was pressed and the second image loaded, it still will be in the center of the screen instead of the upper right. The following code is used:
BufferedImage image = ImageIO.read(images.get(number));
JPanel panel = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, null);
}
};
if (currentPanel != null) {
this.remove(currentPanel);
}
panel.setSize(Gallery.this.getSize());
currentPanel = this.add(panel);
jButton1.setBounds(Gallery.this.getWidth() - jButton1.getWidth(), 0, jButton1.getWidth(), jButton1.getHeight());
panel.add(jButton1);
currentPanel.repaint();
This code is executed once at startup. The JButton then is in the middle.
It is executed again when loading the next Image, JButton now is in correct position.
I already tried many things, like adding the JButton to the JFrame instead, setting JPanels layout to null (makes button invisible), repaint, pack, invalidate, nothing I try seems to work. Is anyone able to instruct Swing to place that JButton in the upper right corner of my JFrame? Thank you a lot!
After cleaning up the mess I programmed there, an easy solution proved to work:
I added a custom JPanel to the JFrame at startup and set a fixed width to the JButton. Here the JPanel:
public class ImagePanel extends javax.swing.JPanel {
Image image;
public Image getImage() {
return image;
}
public void setImage(Image image) {
this.image = image;
}
public ImagePanel() {
initComponents();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
}
I set a fixed width to the JButton and added it to that JPanel:
jButton1 = new JButton();
jButton1.setText("Exit");
imagePanel = new ImagePanel();
imagePanel.setSize(Gallery.this.getSize());
add(imagePanel);
imagePanel.add(jButton1);
jButton1.setBounds(Gallery.this.getWidth() - 50, 0, 50, 30);
jButton1.addActionListener((ActionEvent e) -> exit());
displayImage(0);
The displayImage method consists of these lines:
BufferedImage image = ImageIO.read(images.get(number));
imagePanel.setImage(image);
imagePanel.repaint();
private void renderLevelBackground(Graphics2D g2) {
Image backgroundImage = model.getBackgroundImage();
g2.drawImage(backgroundImage, 0, 0, null);
}
This is my code, I know that the backgroundImage is loaded properly because if I getWidth/Height it gives me the correct values. Is there anyway to test if it's the image or if it's the method somehow? It just won't draw on my screen despite the fact that I've used the drawImage method many times in this project already, all of which work flawlessly.
Thanks
"Is there ever a reason drawImage won't actually draw an image?"
Possibility, there is no image due to a bad path provided. Use ImageIO.read() which will cause an exception if the image file is not found. For example
public class ImagePanel extends JPanel {
private BufferedImage image;
public ImagePanel() {
try {
image = ImageIO.read(getClass().getResource("/resources/image.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
If the image is not found, it will throw an IO exception.
Possibility, the panel to which you are drawing, has no preferred size (0 x 0), and you are adding it a container wit layout that respects preferred sizes, so the ImagePanel will not be able to show the image. For example
public class ImagePanel extends JPanel {
protected void paintComponent(...) {
...
}
JPanel panel = new JPanel(); // default FlowLayout that respects preferred sizes
panel.add(new ImagePanel());
To fix this, you can override the gerPreferredSize() of the ImagePanel
public class ImagePanel extends JPanel {
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
}
Possibility, you are not calling your method within the graphics context of the paint[Component] method.
protected void paintComponent(Graphics 2d) {
super.paintComponent(g);
Grapchics2D g2 = (Graphics2D)g;
renderLevelBackground(g2);
}
Other than that, these are all just guesses, and you should provide some more code code (preferably an MCVE) to help us better help you with the problem.
Possible Alternative to your approach. It seems like (from the little code snippet and it method signature semantics) you want to change the background image, when a level have changed. Consider using setBackgroundImage(BufferedImage image) method in your panel class, when the image is drawn. You can then set the background, whenever need be. Something like
public class BackgroundPanel extends JPanel {
private BufferedImage backgroundImage;
public void setBackgroundImage(BufferedImage image) {
this.backgroundImage = image;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Grpahics2D g2 = (Graphics2D)g;
if (image != null) {
g2.drawImage(backgroundImage, 0, 0, this);
}
}
}
So whenever you call setBackgroundImage, the image will change, and be repainted.
You may need to explicitly tell the JComponent that you are painting onto that it needs to be redrawn with revalidate() and repaint()
I'm working on a assignment for school but I got a problem :P.
I got this code:
public void mouseEntered(MouseEvent e) {
MyPanel b = (MyPanel)e.getSource();
System.out.println("ID: "+b.getId()+"");
b.setColor(Color.blue);
}
In the MyPanel object I got:
public void setColor(Color kleur) {
if(this.getBackground()==Color.white) {
this.setBackground(kleur);
repaint();
}
}
When I enter the panel with my mouse the color flashes that I entered. But I want it to stay the color so I can draw a trail in a Jform with 500 Jpanels(I've added them to a ArrayList but this part works just fine)
What am I doing wrong?
Based on #ErickRobertson's comment on the question, I guess the problem is the following:
Your MyPanel replaces the JPanel#paintComponents() method. Is that possible? If so, you could do the following. In your MyPanel#setColor(Color) method, you don't set the background, but a field containing your new background color:
private Color backgroundColor = Color.white;
public void setColor(Color kleur) {
backgroundColor = kleur;
repaint();
}
Then, in your MyPanel#paintComponents(Graphics):
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
// draw background
g.setColor(backgroundColor);
g.fillRect(0, 0, getWidth(), getHeight());
// draw your stuff here
}
Make sure that only one JPanel is visible at a time.
When you add the JPanels to their parent, are they all going on top of each other? If so, then when you call repaint() on one of them, it's being repainted immediately and you can see it as blue. But as soon as the whole window repaints again, the JPanels are painted in the order they have been added and the last one is ultimately painted on top. This panel still has a white background, so that's what you're seeing.
Make sure only one of these panels are visible at a time, or that you have some plan in place to manage these panels so that only one of them are visible. Otherwise, make sure they are laid out in a grid or some other way so they don't appear on top of each other.
Where is your MouseListener implemented, since you are getting the panel from the MouseEvent. It's easier to have the panels implement the MouseListener and let them decide when to change color for themselves.
class Panel extends JPanel implements MouseListener {
public Panel() {
// Make sure the listener listens
addMouseListener(this);
}
#Override
public void mouseEntered(MouseEvent e) {
setColor(Color.blue);
}
// ... other mouselisteners can be ignored or implemented as needed
}
You can still keep a reference to some other class if you need it to be notified of a mouseenter. Just create a private member and set the reference in the constructor.
public void setColor(Color kleur) {
if(this.getBackground()==Color.white) {
this.setBackground(kleur);
repaint();
}
}
dont use == repalce with equals and try invalidate(. Your code is basically saying only replace background if background is white ???
So im making a gui, and i have a background image for it. i dont know how to make it set as the background, so any help with that would be good. an explination would also be good. also, after we get that image as a background, how do we get the image resize to the size of the window. such as
image.setSize(frame.getHeight(), frame.getWidth());
but i dont know if that would work. the image name is ABC0001.jpg and the frame name is frame. thanks!
To get the image to resize, you can either use
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, getWidth(), getHeight(), this); // draw the image
}
or you can use a componentlistener, implemented like:
final Image img = ...;
ComponentListener cl = new ComponentAdapter() {
public void componentResized(ComponentEvent ce) {
Component c = ce.getComponent();
img = im1.getScaledInstance(c.getWidth(), c.getHeight(), Image.SCALE_SMOOTH);
}
};
Image quality will degrade over time with the second solution, so it is recommended that you keep the original and the copy separate.
Create a class the extends JPanel. Have that class load the image by overriding paintComponent
class BackgroundPanel extends JPanel
{
Image img;
public BackgroundPanel()
{
// Read the image and place it in the variable img so it can be used in paintComponent
img = Toolkit.getDefaultToolkit().createImage("ABC0001.jpg");
}
public void paintComponent(Graphics g)
{
g.drawImage(img, 0, 0, null); // draw the image
}
}
Now that you have this class, simply add this to your JFrame (or whereever you want the background).
//create refrence if you want to add stuff ontop of the panel
private BackgroundPanel backGroundPanel;
//constructor
add(backGroundPanel, BorderLayout.CENTER);
The size of the background will fill the entire frame so no need to scale it unless you want it smaller
I want to write a code to draw a filled oval where ever the mouse is clicked inside a panel. I used to develop some codes but unfortunately when I tried to do the next click the whole panel blanked and new point appeared. I want to keep the previous points and add some new ones by the next user’s click on the panel. How do I implement the paint component of MyPanel? Here is my code; it does not work properly, because it produces some small points instead of rectangle.
class MyPanel extends JPanel {
Point pointClicked;
public MyPanel() {
this.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
pointClicked = e.getPoint();
}
});
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.fillRect(pointClicked.x, pointClicked.y, 1, 1);
}
}
I want to keep the previous points and add some new ones by the next user’s click on the panel.
You need to keep track of each oval painted and repaint all ovals each time the paintComponent() method is called.
Check out Custom Painting Approaches for two different ways to do this