Develop Reference

JFileChooser inside a JFrame makes setVisible() freeze

I have an assignment to show JFileChooser as part of a JFrame. So showing it as a dialog box is out.
I'm doing the most basic approach to adding it as a component to a yet invisible frame, and then the setVisible() call freezes instead of showing the frame.
What irks me the most is that one time out of ten the frame appears with the FileChooser just fine. This makes me think this is a concurrency issue.
Here's the minimal source code that still has the issue.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
class ApplicationFrame extends JFrame {
JFileChooser fileChooser;
public ApplicationFrame(String frameName) {
super(frameName);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
fileChooser = new JFileChooser();
fileChooser.setControlButtonsAreShown(false);
panel.add(fileChooser, BorderLayout.CENTER);
getContentPane().add(panel);
}
}
public class lab7{
public static void main(String args[])
{
ApplicationFrame windowForApplication = new ApplicationFrame("lab7");
windowForApplication.setSize(600,600);
windowForApplication.setVisible(true);
}
}
If you put a println after the final setVisible, it doesn't get called.
If you comment out panel.add(), the frame displays just fine.
What else should I do to display the file chooser?

What irks me the most is that one time out of ten the frame appears with the FileChooser just fine.
All Swing component should be created on the Event Dispatch Thread. So the GUI creating code should be wrapped in a SwingUtilities.invokeLater(...).
Read the section from the Swing tutorial on Concurrency for more information and an example of how this is done.
Your code (as is) actually works for me without problem. I'm using JDK7 on Windows 7, so it could be a version/platform issue. Again make sure the code executes on the EDT.
Also, class names ("lab7") should start with an upper case character. Doesn't matter if this is a SSCCE or not, be consistent.

How can I get my Image to be displayed using Java?

Well basically my image will not display, i'm almost certain it's my file path
(‪" C:\Users\Alex\Desktop\card.png" is what the image properties say is the file path but unless i put double slashes it confuses them for escape sequences. ) If someone has the answer it will be much appreciated. Here's my code:
import java.awt.*;
import javax.swing.*;
public class IDK extends JFrame {
public static void main(String args[]) {
new IDK();
}
public IDK(){
notsure();
}
public void notsure(){
setBounds(420,100,440,400);
setTitle("Frame");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
JLabel label1 = new JLabel("Tell me something");
JLabel image = new JLabel();
label1.setText("New Text");
JTextField text = new JTextField("Insert text",30);
image.setIcon(new ImageIcon("C:\\Users\\Alex\\Desktop\\card.jpg"));
panel.add(label1,image);
panel.add(text);
add(panel);
validate();
panel.setBackground(Color.CYAN);
setVisible(true);
}
}

There is no problem with using "\" so long as it's escaped, as you have done, if your prefer you can use / instead and on Windows the JRE will correct for it.
How ever, you should be adding the image separately, for example...
image.setIcon(new ImageIcon("C:\\Users\\Alex\\Desktop\\card.jpg"));
panel.add(label1);
panel.add(image);
The way you are doing it now assumes that image is a layout constraint for label1, which it isn't.
You should try and avoid using absolute paths and learn to use relative paths and/or embed the resources within the application context, this makes it easier to locate these resources at runtime.

Create a folder in your project and call it i.e. 'resources' and put your image in that folder. This will ensure that given image is on your classpath and can be easily accessed.
Then you can just do :
new ImageIcon("resources/card.jgp")
Problem with accessing outside resources is that special characters needs to be escaped and also if you export the project and give it to someone else, he/she will not have the image required by software ;)

How do you add a jFrame to your main class in Netbeans?

So I have made a Jframe with a lot of elements and buttons and things in it, but I am new to using NetBeans. Upon creating the java application a main class.java was created and upon adding the jframe another jframe.java was created. How do I get the main class to open, read, and run my jframe.java? I can upload the specific code if need be.
Thanks in advance

To call a certain method from another class, you must first create a new object for that class, like this:
Jframe frame = new Jframe();
frame.setVisible(true); //or whatever the method is in jframe.class
Maybe rename the actual class name from jframe to something like frameone. I've heard that naming classes the same as classes in the Java API will cause trouble.
Or, you could put it all in one class, with either two separate methods or put it all in the main method. If this doesn't help, then please paste the exact code on pastebin.org and give a link.

Look at this sample example and learn how to set frame visible
import java.awt.*;
import javax.swing.*;
public class exp{
public static void main(String args[]){
JFrame jf=new JFrame("This is JFrame");
JPanel h=new JPanel();
h.setSize(100,100);
h.add(new JButton("Button"));
h.add(new JLabel("this is JLabel"));
h.setBackground(Color.RED);
jf.add(h);
jf.pack();
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setVisible(true);
}
}
Useful Links
Designing a Swing GUI in NetBeans IDE
Creating a GUI With Swing (As #MadProgrammer Commented)
Learning Swing with the NetBeans IDE

I'm new to this, but I got a form up. Woo hoo!
1) The project created my main function in japp1.java
2) I created a JFrame, file jfMain.java
3) While there was probably a way to reference it as it was, I didn't see how right away, so I moved it to a peer level with the japp1 file, both in a folder called japp1 which will cause them to get built together, having the same parent reference available.
src\
japp1\
japp1.java
jfMain.java
4) Then instead of creating a generic JFrame with a title, I created an instance of my class...
5) I gave it a size...
7) Then showed it...
public static void main(String[] args) {
// TODO code application logic here
JFrame frame = new japp1.jfMain();
frame.setPreferredSize(new Dimension(700, 500));
frame.pack();
frame.setVisible(true);
}
I had already put some code in my jframe... to show a messagedialog with JOptionPane from a mouseclick event on a button and set some text for some textfields.
Hope that helps.

Making a screencast software in java

This is how I plan to make it:
There will be a small JFrame with start and stop buttons to start and stop recording. Clicking start will start a thread that will create a java.awt.Robot that will take repeated screen shots.
Here is where my problem starts. Robot does take a screenshot but
1. The position of the cursor will not be recorded
2. I dont know where the image will be stored. I intend to store them in a folder whose name will be determined using java.util.Date.
3. I dont understand BufferedImage class one bit.
I have finished making JFrame and implemented the thread. I have package that I got from the internet that converts images to avi movies.
Please help me solve the above mentioned three problems.
Edited:
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.File;
public void captureScreen(String fileName) throws Exception {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Rectangle screenRectangle = new Rectangle(screenSize);
Robot robot = new Robot();
BufferedImage image = robot.createScreenCapture(screenRectangle);
ImageIO.write(image, "png", new File(fileName));
}
if you could please explain t he above mentioned code with respect to my problem.

The solution for getting the cursor in the screenshot is to:
figure out the position of the cursor.
java.awt.MouseInfo.getPointerInfo().getLocation()
and place a rendered image of the cursor on top of the screenshot.
Take a look at this: http://docs.oracle.com/javase/tutorial/2d/images/index.html

JInternalFrame acts weird when windows theme changed?

This is my sample code. I am trying to embed a JInternalFrame without titlebar display into a JFrame.
import javax.swing.*;
import javax.swing.plaf.basic.BasicInternalFrameUI;
class A{
public void doThis(){
JFrame fr = new JFrame();
fr.setSize(300,300);
JInternalFrame f = new JInternalFrame();
f.setSize(200,200);
BasicInternalFrameUI ui = (BasicInternalFrameUI) f.getUI();
ui.setNorthPane(null);
f.setVisible(true);
fr.add(f);
fr.setVisible(true);
}
}
class MainA{
public static void main(String a[]){
A obj = new A();
obj.doThis();
}
}
The code works fine and displays a JInternalFrame within a JFrame without titlebar as per the requirement as shown below.
I still have this UI running and at the same time when I try to change my XP theme (via Properties>>Appearance>>Theme), the UI automatically repaints itself to show the JInternalFrame with a titlebar again as shown below.
I just can't understand this bizarre behavior. I have no clue if this is an issue with Java Swing or if it is something related to the OS. Please help me with this!
Why is the UI repainting upon theme change with an enabled titlebar when I explicitly code for the titleBar to be set as null?
PS: OS used is Windows XP and I am not sure if the same behavior is observed in Linux or other versions of Windows

'do' is a keyword in Java, so that code does not compile for me. This code does.
import javax.swing.*;
import javax.swing.plaf.basic.BasicInternalFrameUI;
class A{
public void doIt(){
JFrame fr = new JFrame();
fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
fr.setSize(300,300);
JInternalFrame f = new JInternalFrame();
f.setSize(200,200);
fr.add(f);
BasicInternalFrameUI ui = (BasicInternalFrameUI) f.getUI();
ui.setNorthPane(null);
f.setVisible(true);
fr.setVisible(true);
}
public static void main(String a[]){
A obj = new A();
obj.doIt();
}
}
Some notes/questions:
Swing GUIs should be constructed & altered on the EDT.
Why does the code add a JInternalFrame directly to anything other than a JDesktopPane?
There are slight issues with sizing of the JInternalFrame when changing themes. I suspect it has to do with the lack of validate()/pack() in the code. Since that was not the question, I could not be bothered investigating it further.
Results
I got a 'null result' here using Windows 7. The title bar of the JInternalFrame did not re-appear at any time when changing through (in order):
Forbidden Planet (a custom, simple theme)
Windows 7 (Aero)
Architecture (Aero)
Windows 7 Basic (Basic & High Contrast)
Windows Classic (Basic & High Contrast)
Forbidden Planet