I want this ImagePanel class to display an image that is quite high, so I put it in a JScrollPane. Funny thing is, when I add the ImagePanel to a JFrame it does show the image, but the scroll bar is not there, and there is no way to scroll (not with the mouse either)
When I wrote it, it extended JFrame for easier excess because the part in my programm where I need it takes some time to reach and this class has many methods to draw on the picture. As a JFrame it worked as intended.
Another problem is, that I tried some things to ensure that the width is large enough to display the image, but neither setSize(image.getWidth(), something) , nor setPreferedSize did that. I case it is relevant I add the ImagePanel like this:
all.add(imagePanel, BorderLayout.CENTER);
all.add(contentbox, BorderLayout.EAST);
to a JFrame, so it should stretch, but for some reason that does not work. Contentbox contains ContentPanes, I did not deactivate the LineWarp so it should leave space to the imagePanel (this is not the reason why I can't see the scroll bar, I tried it on an empty JFrame as well with space at both sides^^)
public class ImagePanel extends JPanel {
JLabel imageContainer;
ImageIcon icon;
BufferedImage image;
JScrollPane scroll;
Graphics g;
public ImagePanel (String cName) {
super();
File cFile = new File(cName);
try {
this.image = ImageIO.read(cFile);
} catch (IOException ex) {
ex.printStackTrace();
}
g = image.getGraphics();
g.setColor(Color.black);
icon = new ImageIcon(image);
imageContainer = new JLabel(icon);
scroll = new JScrollPane(imageContainer);
add(scroll);
}
}
Your ImagePanel uses JPanel's default FlowLayout, and this may be the source of your problem, since FlowLayouts can allow components larger than they are without showing the entire component. To test this out, have your ImagePanel use a BorderLayout, and add your JLabel to it BorderLayout.CENTER so that it fills the ImagePanel. Alternatively, you could get rid of the ImagePanel altogether and just return the JScrollPane that holds your JLabel.
Related
I have a JScrollPanel and a JPanel added to it. I would like to draw to the JPanel and make the scrollbars of the JScrollPane appear whenever the drawing exceeds the size of the panel and be able to scroll the drawing both vertically and horizontally.
I have tried consulting with various forums and the official docs and tried a few things (setting the borders, the preferred size, etc.) but none seems to yield the desired effects.
I have a JFrame (with GridBagLayout, btw.) :
JFrame frame1 = new JFrame("Application");
frame1.setVisible(true);
frame1.setMinimumSize(new Dimension(580,620));
frame1.setResizable(false);
frame1.setLocationRelativeTo(null);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
The relevant components are :
JPanel panel1 = new JPanel();
JScrollPane scrollPane = new JScrollPane(panel1);
frame1.add(scrollPane, gbc_panel1); //added with layout constraints
JPanel :
panel1.setBackground(Color.BLACK);
panel1.setPreferredSize(new Dimension(500,500));
panel1.setMinimumSize(new Dimension(360,360));
panel1.setMaximumSize(new Dimension(1000,1000));
JScrollPane :
scrollPane.setAutoscrolls(true);
The relevant code from the action event
of a button that does the drawing :
Graphics g;
g = panel1.getGraphics();
panel1.paint(g);
g.setColor(new Color(0,128,0));
/* this is followed by some more code that
does the drawing of a maze with g.drawLine() methods */
The code does the drawing perfectly, I just can't seem to figure it out how to make the scrolling and dynamic resizing happen.
I would appreciate any helpful comments or remarks!
Thank you!
Ultimately rewriting the paint method did the trick as #MadProgrammer suggested. I was just hoping that I could do the painting without having to define my custom JPanel class, but looks like it doesn't work that way.
The custom class looks like this:
class Drawing extends JPanel {
int mazeSize;
public Drawing(JTextField jtf)
{
try {
this.mazeSize = Integer.parseInt(jtf.getText());
}
catch (Exception e)
{
JOptionPane.showMessageDialog(this, "ERROR! Invalid size value!");
}
} // the constructor gets the size of the drawing from a textField
public Dimension getPreferredSize() {
return new Dimension(mazeSize*10,mazeSize*10);
} //getPreferredSize - this method is used by the scroll pane to adjust its own size automatically
public void drawMaze (Graphics g)
{
/* some irrelevant code that does the desired drawing to the panel by calling g.drawLine()*/
} // drawMaze method that does the de facto drawing
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
drawMaze(g);
}// paintComponent() #Override method - this was the tricky part
}//Drawing JPanel subclass
It is also worth noting (if some noob like myself happens to stumble upon this question), that after instantiating the new JPanel subclass in the action event, I had to add it to the JScrollPanel in the following way, instead of just simply using its add() method:
Drawing drawPanel = new Drawing(textfield1);
scrollPane.getViewport().add(drawPanel);
Again, thanks for the suggestion!
Once finished with the program (a random maze generator that uses a recursive backtracking algorithm), I will make the source code available at my github profile.
We're about to create an online based Space Invaders-game with implemented graphics. I've been reading about JFrames, JPanels and JLabels in order to create a window with a grid where the ships and monsters will be placed in.
So, here's the thing, I've been looking through the different layouts that exists, but nothing really seems to fit our purpose. I would like a simple JFrame with the possibility of placing JLabel-objects on a certain position (with setBounds(), setLocation() or something similar). This requires setLayout(null) which I've heard isn't a good solution? I was thinking of having objects in a fixed 30x30px size, and a fixed window size of 600x600px (giving me a grid of 20*20).
Anyhow, I've been trying to get it to work with setLayout(null), but without any results. If I apply a layout, say FlowLayout, the ship is visible, but stuck in either LEFT, CENTER or MIDDLE.
public class GUI extends JFrame {
JPanel p = new JPanel(null);
public GUI() {
try{
this.setContentPane(new JLabel(new ImageIcon(ImageIO.read(new File("graphics/bg.png")))));
}catch(IOException e) {
System.out.println("Image does not exist");
}
this.setLayout(null);
this.setResizable(false);
this.setSize(600,600);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public void placeShip1() {
ImageIcon ship2 = new ImageIcon("graphics/ship2.png");
JLabel imageLabel = new JLabel(ship2);
imageLabel.setBounds(200,200,30,30);
p.add(imageLabel);
p.setOpaque(false);
p.setSize(600, 600);
this.add(p);
this.setVisible(true);
}
}
I really can't see why it doesn't work. I mean, all I want is my JFrame with a background image and with an object on a certain position, but instead the object doesn't show at all.
The main reason for wanting to use setLayout(null) is because I was thinking of using a method translating our grid coordinates to the JFrame, simply mapping each coordinate to respective cell.
I am creating a simple GUI, and I want to have a background image (2048 X 2048) fill up the whole window and a square to the left top corner where the occasional 64 X 64 image can be loaded. How can this be done?
I already know how to make the JFrame a set size, its the image loading I need help with.
This is a simple example for adding the background image in a JFrame:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class BackgroundImageJFrame extends JFrame
{
JButton b1;
JLabel l1;
public BackgroundImageJFrame()
{
setTitle("Background Color for JFrame");
setSize(400,400);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
/*
One way
-----------------
setLayout(new BorderLayout());
JLabel background=new JLabel(new ImageIcon("C:\\Users\\Computer\\Downloads\\colorful design.png"));
add(background);
background.setLayout(new FlowLayout());
l1=new JLabel("Here is a button");
b1=new JButton("I am a button");
background.add(l1);
background.add(b1);
*/
// Another way
setLayout(new BorderLayout());
setContentPane(new JLabel(new ImageIcon("C:\\Users\\Computer\\Downloads\\colorful design.png")));
setLayout(new FlowLayout());
l1=new JLabel("Here is a button");
b1=new JButton("I am a button");
add(l1);
add(b1);
// Just for refresh :) Not optional!
setSize(399,399);
setSize(400,400);
}
public static void main(String args[])
{
new BackgroundImageJFrame();
}
}
Click here for more info
The best way to load an image is through the ImageIO API
BufferedImage img = ImageIO.read(new File("/path/to/some/image"));
There are a number of ways you can render an image to the screen.
You could use a JLabel. This is the simplest method if you don't want to modify the image in anyway...
JLabel background = new JLabel(new ImageIcon(img));
Then simply add it to your window as you see fit. If you need to add components to it, then you can simply set the label's layout manager to whatever you need and add your components.
If, however, you need something more sophisticated, need to change the image somehow or want to apply additional effects, you may need to use custom painting.
First cavert: Don't ever paint directly to a top level container (like JFrame). Top level containers aren't double buffered, so you may end up with some flashing between repaints, other objects live on the window, so changing it's paint process is troublesome and can cause other issues and frames have borders which are rendered inside the viewable area of the window...
Instead, create a custom component, extending from something like JPanel. Override it's paintComponent method and render your output to it, for example...
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(img, 0, 0, this);
}
Take a look at Performing Custom Painting and 2D Graphics for more details
I used a very similar method to #bott, but I modified it a little bit to make there be no need to resize the image:
BufferedImage img = null;
try {
img = ImageIO.read(new File("image.jpg"));
} catch (IOException e) {
e.printStackTrace();
}
Image dimg = img.getScaledInstance(800, 508, Image.SCALE_SMOOTH);
ImageIcon imageIcon = new ImageIcon(dimg);
setContentPane(new JLabel(imageIcon));
Works every time. You can also get the width and height of the jFrame and use that in place of the 800 and 508 respectively.
You can do:
setContentPane(new JLabel(new ImageIcon("resources/taverna.jpg")));
At first line of the Jframe class constructor, that works fine for me
I'm trying to open a window that has both an image and buttons in it. But I can't seem to figure out how to add the button. The image displays great and the menu works fine, but no matter where I add the button (into the JLabel, JPanel, or JFrame), it doesn't ever show...
Main:
public static void main(String[] args) {
GUI myGUI = new GUI();
myGUI.show();
}
GUI class: openImage is called when using the menu. The image then displays, but no button.
private JFrame myFrame;
private JPanel myPanel;
private JLabel myLabel;
public GUI()
{
myFrame = new JFrame();
initializePanel();
}
public void show()
{
myFrame.setSize(600,600);
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myFrame.addMouseListener(this);
setupMenu(myFrame);
myFrame.setVisible(true);
}
private void initializePanel()
{
myPanel = new JPanel();
myPanel.setPreferredSize(new Dimension(500,500));
//myPanel.setLayout(new BorderLayout());
}
private void openImage(String fileName)
{
try {
myImage = ImageIO.read(new File(fileName));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
myLabel = getJLabel();
JButton button = new JButton("ButtonClick");
button.addActionListener(this);
myFrame.setContentPane(myLabel);
myPanel.add(button);
myFrame.getContentPane().add(myPanel);
myFrame.pack();
myFrame.setSize(600,600);
}
private void setupMenu(JFrame window) {
JMenuBar menubar = new JMenuBar();
JMenu file = new JMenu("File");
JMenuItem open = new JMenuItem("Open");
open.addActionListener(this);
file.add(open);
menubar.add(file);
window.setJMenuBar(menubar);
}
Your main issue is your setting the contentPane to be a JLabel -- don't do this! The contentPane needs to be opaque, needs to be built to be easily used as a Container and in your case, really should be a JPanel. JLabel I believe uses a null layout so it's no surprise that your code shows no button. If you want to show a background image, make have myPanel constructed from an anonymous class that extends JPanel, override the paintComponent method in this class (calling super.paintComonent first in the method), and draw the image in this method. Then you can add components to the contentPane which will now use a FlowLayout (the default for a JPanel) and it will be opaque by default.
Also, if your goal is to swap items displayed in your GUI, use a CardLayout to do the swapping for you as this layout makes swapping components a breeze.
really don't know, depends of method(s) how you are added picture to the JLabel, JPanel, or JFrame, but maybe for simle Container that contains a few, only one-two JComponents is there crazy idea, without side effects, with idea to display picture and to add there JButton:
JLabel is very similair JComponent to the JPanel, and is by default translucent and very simple implements Icon/ImageIcon, then you'll only to call myLabel.setIcon(myPicture)
to the all of JComponents you are/could be able to add another JComponent by using some of LayoutManager (Box, Flow, GridBagLayout)
You tried to set the label as the content pane and then tried to add the panel to that image which doesn't make sanse at all.
Change it so you add the label to the panel and have the panel as content pane:
Like this:
You have this line which is the problem. It doesn't make much sense:
myFrame.setContentPane(myLabel);
Try instead:
myFrame.getContentPane().add(myLabel);
Just wondering if you could help wanting to produce an activity stream in Java, the idea was to have a JLabel and text area followed by a divider be displayed on a screen and then repeated X amount of times according to what data was in a database.
What I was wondering is how could I possibly repeat the placing the jlabel, text area, and diveder on the screen above the last rendered objects on the fly and all displayed correctly no matter the size of the text area of each set of object sort of like the image below.
Hope I made it clear as I could thanks
Just provide your own version of a JPanel containing all these things and place them in a scrollpane that will care about having a long list of these panels..
class MyPanel extends JPanel
{
ImageIcon icon;
JTextArea textArea;
MyPanel(ImageIcon icon, String text)
{
this.icon = icon;
this.setPreferredSize(/*max size of your panel */)
textArea = new JTextArea(10, 50);
textArea.append(text);
//the default manager will be a flow layout for single jpanels
this.add(icon);
JScrollPane sp = new JScrollPane(textArea);
sp.setPreferredSize(new Dimension(/* size of your text label */));
this.add(new JScrollPtextArea);
}
}
class MyContainer extends JFrame
{
JPanel container;
JScrollPane spContainer;
MyContainer()
{
container = new JPanel()
container.setGridLayout(100,1); //100 elements max
spContainer = new JScrollPane(container);
spContainer.setPreferredSize(/* max size of whole thing */)
this.add(spContainer);
pack();
}
void addElement(MyPanel panel)
{
container.add(panel);
this.pack();
}
}
It's not fully working (I just wrote it) but it should give you the idea..