First of all: sorry, if this question was asked before, but I cannot seem to find an answer anywhere, so here we go:
I am trying to get a canvas element to show while it being added to a panel with a titled border around the panel. Here is my code.
public class TestClass extends JFrame{
private TestClass() {
GuiCanvas canvas = new GuiCanvas();
setTitle("TestClass");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(1300, 800);
Border menuBorder = BorderFactory.createTitledBorder(
BorderFactory.createLineBorder(Color.LIGHT_GRAY), "Overview");
JPanel controlpanel = new JPanel();
JPanel panelCanvas = new JPanel();
panelCanvas.setBorder(menuBorder);
panelCanvas.add(canvas);
controlpanel.setLayout(new GridLayout(3, 1));
controlpanel.add(panelCanvas);
add(controlpanel);
setLocationRelativeTo(null);
setVisible(true);
System.out.println(canvas.getBounds());
}
private class GuiCanvas extends Canvas {
GuiCanvas() {
setBackground(Color.LIGHT_GRAY);
}
#Override
public void paint(Graphics g) {
g.drawLine(20, 20, 20, 200);
}
}
public static void main(String[] args) {
new TestClass();
}
}
The above code results in an empty panel with a titled border when it should show the defined line I draw in the GuiCanvas-Class. Am I missing something here? Is it even possible to add a canvas-element to a panel? Thanks for your help in advance :)
If you want the canvas to stretch to the size of the panel, change:
JPanel panelCanvas = new JPanel();
To:
JPanel panelCanvas = new JPanel(new GridLayout());
See also this answer:
It is indeed possible to add a Canvas object to a JPanel.
Your problem lies in the fact that your Canvas has no defined size.
What you need are the two following lines
canvas.setPreferredSize(new Dimension(1300,300));
/*
*
*/
this.pack();
This will place your canvas inside the panelCanvas border, displaying a black vertical line on a light gray background.
Related
So basically when I add a button it essentially pushes the black rectangle drawn in this program down, putting it out of its given location. How would you fix this?
import javax.swing.*;
import java.awt.*;
public class Grid {
public class homeGraphics extends JComponent {
homeGraphics() {
setPreferredSize(new Dimension(450, 600));
}
public void paint(Graphics g) {
super.paint(g);
g.fillRect(200, 275, 50, 50);
}
}
public void homeFrame() {
JFrame frame1 = new JFrame();
frame1.setSize(450, 600);
frame1.setResizable(false);
frame1.setDefaultCloseOperation(frame1.EXIT_ON_CLOSE);
JButton playButton = new JButton("Play");
playButton.setPreferredSize(new Dimension(60, 30));
JPanel panel1 = new JPanel();
panel1.add(playButton);
panel1.add(new homeGraphics());
frame1.add(panel1);
frame1.setVisible(true);
}
public static void main(String args[]) {
Grid frame = new Grid();
frame.homeFrame();
}
}```
it essentially pushes the black rectangle drawn in this program down, putting it out of its given location.
What do you mean out of its location? Painting is always done relative to the component. So your painting will always be done at (200, 275) of the component.
If you are attempting to paint at (200, 275) relative to the "frame", then don't. That is NOT how painting works.
Other problems with your code:
Don't attempt to set the size of your frame. If the custom panel is (450, 600) how can the frame possibly be the same size? The frame also contains the "title bar" and "borders". Instead of using setSize(), you invoke frame.pack()just beforeframe1.setVisible(….)`.
Class names start with an upper case character. Learn by example. Have you ever seen a class name in the JDK that doesn't start with an upper case character?
Custom painting is done by overriding paintComponent(…), not paint().
By default a JPanel uses a FlowLayout. So what you see it the button on one line and then the "HomeGraphics" class is too big to fit on the same line so it wraps the to the second line.
You should be more explicit when you do frame layout. So your code should be something like:
JPanel wrapper = new JPanel();
wrapper.add( playButton );
//JPanel panel1 = new JPanel();
//panel1.add(playButton);
//panel1.add(new homeGraphics());
JPanel panel1 = new JPanel( new BorderLayout() );
panel1.add(wrapper, BorderLayout.PAGE_START);
panel1.add(new HomeGraphics(), BorderLayout.CENTER);
Now the code shows your layout attempt more clearly.
I'm trying to add a JScrollPane to an JPanel from a separate class. And thanks to some questions, which were asked so far, I could help myself create them. But my problem is still a little bit special.
I want to display an image on a JPanel and if the image is to large for the panel, I want to add scrollbars. But the scrollbars won't appear.
(When I set the ScrollPaneConstants to ****_SCROLLBAR_ALWAYS the frame of the bar appears, but without the bars to scroll).
I guess i have to connect the imagesize with the bars, so that they appear?
Some pieces of my code:
MainWindow
public class Deconvolutioner extends JFrame
{
Draw z;
Picturearea picturearea;
class Draw extends JPanel
{
public void paint(Graphics g)
{
}
}
public Deconvolutioner()
{
setTitle("Deconvolutioner");
setLocation(30,1);
setSize(1300,730);
super.setFont(new Font("Arial",Font.BOLD,11));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
FlowLayout flow = new FlowLayout(FlowLayout.CENTER);
this.setLayout(flow);
picturearea = new Picturearea();
picturearea.setLayout(new GridBagLayout());
JScrollPane scrollPane = new JScrollPane(picturearea,
ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setPreferredSize(new Dimension(1000, 664));
getContentPane().add(scrollPane, flow); // add scrollpane to frame
add(z = new Draw());
setVisible(true);
}
}
JPanel Class
public class Picturearea extends JPanel
{
BufferedImage image;
int panelWidth, panelHeight, imageWidth, imageHeight;
public Picturearea()
{
setBackground(new Color(210,210,210));
setBorder(LineBorder.createBlackLineBorder());
setVisible(true);
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
public void setPicture(BufferedImage picture)
{
try
{
image = picture;
}
catch (Exception e)
{
System.err.println("Some IOException accured (did you set the right path?): ");
System.err.println(e.getMessage());
}
repaint();
}
}
Thanks for your time.
The problem is that the JScrollPane has no way to know if it should display scroll bars or not, since the Picturearea it contains doesn't tell anything about its preferred size (or rather, it returns the preferred size based on its layout and on the components it contains. But since it doesn't contain any component, the returned preferred size is probably (0, 0)).
I would simply use a JLabel instead of the custom Picturearea class. A JLabel can display an image just fine, and it returns the appropriate Dimension when asked for its preferred size.
You can create a JLabel first and then add the Label to JPanel picturearea before creating instance for JScrollPane .
Have a try and it will work.
Example code is as follows:
JLabel imageLabel = new JLabel(new ImageIcon("d:\\099.jpg"));
picturearea.add(imageLabel);**
JScrollPane scrollPane = new JScrollPane(picturearea,
ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
I'm currently trying to draw shapes on a JPanel, which is within another JPanel, within a JFrame.
I've searched Google and Youtube and found out how to draw shapes within a JFrame that has one panel, but have found nothing which can help me with what I'm doing. (maybe I'm not seeing something).
Code I've seen so far:
public class GameScreen
{
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.red);
g.drawRect(100, 10, 30, 40);
}
public static void main(String[] args)
{
GameScreen gs = new GameScreen();
JFrame f = new JFrame();
f.setTitle("");
f.setSize(400,400);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(gs);
}
This is all good for when I'm dealing with just one panel, but I wanna display shapes on a panel which is within the 1'st panel I've created.
Add a JPanel to the JFrame in the same way as you're doing now, but do it with your own subclass of JPanel.
class MyPanel extends JPanel {
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.red);
g.drawRect(100, 10, 30, 40);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400,400); // As suggested by camickr
}
}
You can add this to a JPanel which sits within the JFrame
public static void main(String[] args)
{
MyPanel mp = new MyPanel();
JPanel jp = new JPanel();
jp.add(mp);
JFrame f = new JFrame();
f.setTitle("");
f.setSize(400,400);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(jp);
}
This can work for components within components, if you add them as children components. The key is to extend the component and override the methods you wish to change.
This is all good for when I'm dealing with just one panel,
The code you posted works fine because a frame uses a BorderLayout. So, when you add your panel to the frame is will increase in size and your custom painting will be seen.
I wanna display shapes on a panel which is within the 1'st panel I've created.
When you create a panel it uses a FlowLayout by default. When you add a custom painting panel to that panel it will be displayed at its preferred size, which will be (0, 0) since you didn't specify the preferred size.
On the panels that do custom painting you also need to implement the getPreferredSize() method so the layout manager knows how to arrange the panels. For example:
public Dimension getPreferredSize()
{
return new Dimension(200, 200);
}
I am trying to place a JPanel on top of another JPanel which contains a JTextArea and a button and i want to the upper apnel to be transparent. I have tried it by making the setOpaque(false) of the upper panel. but it is not working. Can anyone help me to get through this? Thanks in advance!
public class JpanelTest extends JPanel
{
public JpanelTest()
{
super();
onInit();
}
private void onInit()
{
setLayout(new BorderLayout());
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.add(new JTextArea(100,100),BorderLayout.CENTER);
panel.add(new JButton("submit"),BorderLayout.SOUTH);
JPanel glass = new JPanel();
glass.setOpaque(false);
add(panel,BorderLayout.CENTER);
add(glass,BorderLayout.CENTER);
setVisible(true);
}
public static void main(String args[])
{
new JpanelTest();
}
}
Indeed, it would be useful to tell the reason why you want panels one over another.
Starting with your code, and changing it a lot, I got it to work, but it might not do what you expect...
import java.awt.*;
import javax.swing.*;
public class Test extends JFrame
{
public Test()
{
super();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(500, 200);
onInit();
setVisible(true);
}
private void onInit()
{
JLayeredPane lp = getLayeredPane();
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.add(new JTextArea(), BorderLayout.CENTER);
panel.add(new JButton("Submit"), BorderLayout.SOUTH);
panel.setSize(300, 150); // Size is needed here, as there is no layout in lp
JPanel glass = new JPanel();
glass.setOpaque(false); // Set to true to see it
glass.setBackground(Color.GREEN);
glass.setSize(300, 150);
glass.setLocation(10, 10);
lp.add(panel, Integer.valueOf(1));
lp.add(glass, Integer.valueOf(2));
}
public static void main(String args[])
{
// Schedule a job for the event-dispatching thread:
// creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new Test();
}
});
}
}
If totally transparent, well, it is like it isn't here! When opaque, it just covers some of the GUI, but doesn't prevent mouse clicks, for example.
1) there are a few ways, there no issue to put JPanel, with covering full JFrames/JPanel area or only part of Rectangle / Dimension that returns JFrames/JPanel
use JLayer(Java7) based on JXLayer (Java6)
use GlassPane
use JViewport
use OverlayLayout
use transucent JDialog / JWindow
2) everything depends of if you want to protect against mouse and key events from the top layer to bottom, or not (to avoiding redispatch events from - to and vice versa)
Check out this tutorial on using Swing Root Panes.
The glass pane is useful when you want to be able to catch events or paint over an area that already contains one or more components. For example, you can deactivate mouse events for a multi-component region by having the glass pane intercept the events. Or you can display an image over multiple components using the glass pane.
I have a canvas and I want when mouse entered it, some transparent Jpanel containing some components displayed on top of my canvas. I used JlayeredPane for this; but as you see in following example when I want to display transparent panel on top of canvas, by adding it to jLayeredPane on upper layer, It's background is shown as color of the panel that is under canvas.
public class NewClass {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setSize(200 , 200);
JLayeredPane layeredPane = new JLayeredPane();
frame.setContentPane(layeredPane);
JPanel canvasPanel = new JPanel();
canvasPanel.setLayout(new GridLayout());
canvasPanel.setBackground(Color.RED);
Canvas canvas = new Canvas();
canvas.setBackground(Color.BLACK);
canvasPanel.add(canvas);
layeredPane.add(canvasPanel , JLayeredPane.PALETTE_LAYER);
canvasPanel.setSize(200 , 200);
JPanel transparentPanel = new JPanel();
transparentPanel.setSize(100 , 100);
transparentPanel .setOpaque(false);
transparentPanel.add(new JButton("button"));
layeredPane.add(transparentPanel , JLayeredPane.DRAG_LAYER);
frame.setVisible(true);
}
}
how can I show transparent panel on canvas such that, It's background seems as canvas?
I don't understand the problem, when I ran the code as is it resulted in the button on top of a red square on a black background
If not working for you, try setting the transparentPanel background color to red (same as canvasPanel)
Although this probably wouldn't work for non solid backgrouds