I'm pulling my hair out on this one. Many questions like this here on SO, but I can't get it to work.
I'm trying to add an image to an existing JPanel. The problem is getting the image to be visible in the JPanel. The code runs, but the image is nowhere..
Here's my code:
private void loadImgBtnActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
int returnVal = fileChooser.showOpenDialog(this);
if (returnVal == JFileChooser.APPROVE_OPTION)
{
File file = fileChooser.getSelectedFile();
BufferedImage myPicture = null;
try {
myPicture = ImageIO.read(file);
} catch (IOException ex) {
Logger.getLogger(GUI.class.getName()).log(Level.SEVERE, null, ex);
}
JLabel picLabel = new JLabel(new ImageIcon(myPicture));
imagePnl2.add(picLabel);
imagePnl2.repaint();
imagePnl2.revalidate();
}
else
{
System.out.println("File access cancelled by user.");
}
}
In this question the problem was the missing revalidate(). But that makes no difference here.
What am I missing?
In this question the problem was the missing revalidate(). But that makes no difference here.
Order is important. The code should be:
panel.add(...);
panel.revalidate();
panel.repaint();
The revalidate() invokes the layout manager which in turn determines the components size and location. By default components have a size of (0, 0) so if you invoke repaint() first there is nothing to paint.
Also, an easier solution would be to just add an empty label to your panel when you create the GUI. Then when you want to add the image you can just do:
label.setIcon(...);
The setIcon() method automatically does the revalidate() and repaint() for you.
Related
Is this the correct way to add an ImageIcon to a JLabel? It doesn't seem to be working when I call the second method.
What type should addCarIcon() be?
//return JLabel that is null
JLabel findEmptySpace()
{
return parkingSpace[emptySpaceNo()];
}
//set icon JLabel
void addCarIcon()
{
ImageIcon carIcon = new ImageIcon("car.png");
findEmptySpace().setIcon(carIcon);
}
//return JLabel that is null
JLabel findEmptySpace()
{
return parkingSpace[emptySpaceNo()];
}
//set icon JLabel
void addCarIcon()
{
// ImageIcon carIcon = new ImageIcon("car.png");
ImageIcon carIcon = new ImageIcon(getClass().getResource("car.png"), null);
findEmptySpace().setIcon(carIcon);
}
I do not reccomend to use ImageIcon(String filename) construction in case of problem, depending on file pakaging. It could work when you run it from IDE, and not work whe you run it from runnable jar.
P.S. Some time ago, I've created IconManager utils to use ico files instead of set of png files. You can test it, maybe it could be useful for you. (This is a link to GitHub: https://github.com/oleg-cherednik/IconManager)
I am trying to add a JFileChooser to JPanel. Sometimes it works properly and sometimes it shows just the JPanel without the JFileChooser dialogue box. Now i actually don't know what to do . Can anyone help me please?
Here is my code(It is a method):
public File chooseFileFromComputer(){
methodPanel = new JPanel();
methodPanel.setLayout(null);
methodFrame = new JFrame();
methodFrame.setTitle("File Chooser");
methodFrame.setVisible(true);
BufferedImage removeJavaImage = new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);
methodFrame.setIconImage(removeJavaImage);
methodLabel = new JLabel("Choose a file: ");
methodLabel.setBounds(10, 10, 80, 20);
methodPanel.add(methodLabel);
fileChooser = new JFileChooser();
fileChooser.setMultiSelectionEnabled(false);
fileChooser.setBounds(10, 35, 550, 500 );
fileChooser.setVisible(true);
add(fileChooser);
/**
* Action Events #********AE*******#
**/
fileChooser.addActionListener( new ActionListener(){
public void actionPerformed(ActionEvent actionEvent) {
String command = actionEvent.getActionCommand();
if (command.equals(JFileChooser.APPROVE_SELECTION)) {
selectedFile = fileChooser.getSelectedFile();
methodFrame.setVisible(false);
} else if (command.equals(JFileChooser.CANCEL_SELECTION)) {
methodFrame.setVisible(false);
}
}
});
//End of Action Events #________AE_______#
methodPanel.add(fileChooser);
methodFrame.setContentPane(methodPanel);
methodFrame.setResizable(false);
methodFrame.setSize(600, 600);
methodFrame.setDefaultCloseOperation(EXIT_ON_CLOSE);
return selectedFile;
}
You are using a null layout and calling setBounds(...) on your components. While this may seem to a newbie the better way to create complex GUI's, it's a fallacy, and more you create Swing GUI's the more you learn to respect and use the layout managers and see that these creatures help immensely in creating flexible, beautiful and if need be, complex GUI's.
add your components to the JFrame, and only then call setVisible(true) on the JFrame.
It doesn't look like you should be using a JFrame at all if you are setting it visible and invisible. Perhaps you really want to use a JDialog or even a free standing JFileChooser dialog.
Edit
You are adding the JFileChooser to more than one container:
add(fileChooser); // ******************* here *************
fileChooser.addActionListener( new ActionListener(){
private File selectedFile;
public void actionPerformed(ActionEvent actionEvent) {
String command = actionEvent.getActionCommand();
if (command.equals(JFileChooser.APPROVE_SELECTION)) {
selectedFile = fileChooser.getSelectedFile();
methodFrame.setVisible(false);
} else if (command.equals(JFileChooser.CANCEL_SELECTION)) {
methodFrame.setVisible(false);
}
}
});
methodPanel.add(fileChooser); // ******** here *******
You can't do this. Only add it to one container, else it may not show correctly or show at all.
Edit 2
You're returning the wrong result from your method. You return the selectedFile variable, but do so before it is ever set since it is set by the ActionListener which is called long after this method returns.
Solution: again, don't use a JFrame here where a modal JDialog would work much better. If you used a modal dialog and returned after the ActionListener is done, your code would work.
Edit 3
But again for my money, I'd just use a JFileChooser as a modal dialog. For example:
JFileChooser fileChooser = new JFileChooser();
fileChooser.setDialogTitle("Choose a File");
// don't use null in the method below but rather a reference to your current GUI
int response = fileChooser.showOpenDialog(null);
if (response == JFileChooser.APPROVE_OPTION) {
File file = fileChooser.getSelectedFile();
System.out.println(file);
}
Your JPanel - methodPanel has null layout methodPanel.setLayout(null); try it with for example with FlowLayout
I don't know exactly about your class wherether extends jpanel or not , but you should add filechooser to methodPanel together with label. I tested your code is ok except actionPerform.
methodPanel.add(fielChooser);
I suggest, just try it.
I want the user to be able to click a button and choose and image which'll be displayed on the screen.
This is the code I wrote. It doesn't seem to work:
uploadBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int retVal = fc.showOpenDialog(EditImage.this);
if(retVal == JFileChooser.APPROVE_OPTION){
File file = fc.getSelectedFile();
try{
Image img = ImageIO.read(file);
if(img==null){
//TODO: THE FILE IS NOT AN IMAGE. ERROR
}
ImageIcon ic = new ImageIcon(img);
JLabel imageLabel = new JLabel(ic);
imagePreview.add(imageLabel);
}
catch(IOException ex){
//TODO: THE FILE COULD NOT BE OPENED.
}
}
}
});
imagePreview is a JPanel that I've got somewhere on the screen.
What am I doing wrong?
agree with other answers here is required to call container.revalidate() and (there is an Image, then to required) container.repaint()
but this logics is wrong, you couldn't, why to add/remove JComponent for showing another Image, there no reason for, you can to switch betweens ImageIcons in JLabel - JLabel.setIcon(file)
and there is another issue, Images can increasing used JVM memory, you have to call Icon/ImageIcon.flush() before is added to JLabel.setIcon(a few times mentioned here)
Is imagePreview already visible when you add the JLabel to it? If so, you can't just add components to a visible container; you have to revalidate it.
call imagePreview.revalidate(); imagePreview.repaint() after imagePreview.add(imageLabel);, that needed if you add components to visible container.
Hey All
I want to set a Background for my JWindow. I used setIconImage method in JWindow. but it's not working
How knows what the problem is?
public MainMenu() throws Exception {
try {
bg = ImageIO.read(new File("pics" + File.separator
+ "mainMenuBackground.jpg"));
content = new JWindow(this);
content.setIconImage(bg);
gs.setFullScreenWindow(content);
content.repaint();
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.repaint();
} catch (Exception e) {
throw new Exception("Some files are unavailable");
}
}
This lines of code makes a Full-screen window with no background image. why?
How can i fix it?
The setIconImage is for the window icon, not for the background.
Try for instance setBackground. If you want some custom background image, you probably have to either override some paint(Graphics g) method, or set some content pane / add some component that paints the image.
I am doing slideshow of images program in java using timer.
In timer event listner i have added code to chnage image but image is not changing.
Below is the code i have written
class ImagePanel extends JPanel {
private Image backgroundImage;
public ImagePanel(Image backgroundImage) {
super();
this.backgroundImage = backgroundImage;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(this.backgroundImage, 0, 0, null);
}
}
public class A extends JFrame{
static int counter;
List<String> imagePaths;
int nimgpaths=0;
static A frame = new A();
public static void main(String[] args) {
frame.setSize(1024, 768);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getPath();
/* Getting required image */
Image backgroundImage = null;
String pathToTheImage = "C:\\Documents and Settings\\Administrator\\My Documents\\My Pictures\\civ1.JPG";
try {
backgroundImage = ImageIO.read(new File(pathToTheImage));
} catch (IOException e) {
e.printStackTrace();
}
/* Initializing panel with the our image */
ImagePanel panel = new ImagePanel(backgroundImage);
frame.getContentPane().add(panel);
frame.setVisible(true);
frame.timerEvent();
//frame.show();
}
public void timerEvent(){
Timer timer = new Timer(5000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Time event occured");
if(counter > nimgpaths)
counter=0;
String imgPath=imagePaths.get(counter);
Image backgroundImage = null;
try {
backgroundImage = ImageIO.read(new File(imgPath));
}catch (Exception e1) {
e1.printStackTrace();
}
/* Initializing panel with the our image */
frame.removeAll();
ImagePanel panel = new ImagePanel(backgroundImage);
panel.repaint();
//panel.setBackground(backgroundImage);
frame.getContentPane().add(panel);
}
});
timer.start();
}
// To get path of images
public void getPath(){
DbOps db=new DbOps();
imagePaths=db.getPath();
nimgpaths=imagePaths.size();
for(Iterator i=imagePaths.iterator();i.hasNext();){
System.out.println((String)i.next());
}
}
}
Why are you using a custom panel and painting?
Your code is simply painting the image at its preferred size. This functionality is available when you use a JLabel. Then when you use the label all you need to do is use:
label.setIcon(....);
when you want to change the image. Read the section from the Swing tutorial on How to Use Icons for more information.
The only reason to create a custom component is if you plan to scale the image or do something fancy like that. If this is the case then you can use something like the Background Panel which supports scaled images as well as a setImage() method so you can change the image dynamically.
A much better design for ImagePanel would let you just replace the image, rather than removing the component. If you do have to replace a visible component, though, you have to call validate() on its container, or the new one isn't going to show up (most of the time, anyway.) I think that's your problem here.
frame.removeAll() is not doing what you would expect - it is removing the components from the frame itself rather than removing the components from the content pane of the frame. Change the code at the end of the timer's action listener to something like this to fix it:
ImagePanel panel = new ImagePanel(backgroundImage);
frame.getContentPane().removeAll();
frame.getContentPane().add(panel);
frame.getContentPane().invalidate();
frame.getContentPane().validate();
Your concept itself is wrong.
You can refresh the panel like so:
public void refreshPanel(JPanel panel){
panel.removeAll();
panel.invalidate();
panel.validate();
}
Problem:
I see in your code that you are trying to create more than one object of the same panel, which you need to refresh.
It would be better to create one panel object and refresh that object.
ImagePanel panel = new ImagePanel(backgroundImage);
Hope you can understand what I wanted to explain to you.
If you are still confused then let me know.