Develop Reference

netbeans setDefaultCloseOperation

I am trying to set the default close operation in NetBeans 8.0.2 (in Ubuntu 14.04 on an older Asus gaming laptop.) My program is very large but uses no JFrame or java.swing components.
I merely need to save some values when the "x" in the lower right corner is clicked (this is one usual way to stop execution of a java program in NetBeans.)
I found suggestions that involved swing & JFrame, but it wasn't clear just where to insert the code:
DefaultApplicationView view = new DefaultApplicationView(this);
javax.swing.JFrame frame = view.getFrame();
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
frame.addWindowListener(new WindowAdapter(){
public void WindowClosing(WindowEvent e){
System.out.println("CLOSING");
}
}
show(view);
I also found a set of instructions that I think I would prefer to use, but the post is old enough that my NetBeans doesn't have the tabs/menu-items referred to:
Set Window to Design Mode by clicking the 'Design' Tab
In the Navigator: Right click the 'JFrame' -> 'Properties'
In the Properties Tab: Set 'defaultCloseOperation' (top of the list) to 'DO_NOTHING'
Select 'Events' Tab
Scroll down to 'windowClosing'
Click on the "..." button on the right of the event to bring up the custom editor
Click 'Add...' and name the handler (i.e. custom function that you want to have execute on click of the 'X', or window close event).
Click 'Ok'
Netbeans now automatically creates the function and takes to you the function body in the source view
Now simply add what you want to do here: eg. dispose(), or system.exit or pintln(), or whatever your heart desires, as long as its JAVA and makes sense to the app.
Then there are a few other possibly relevant posts, but they all explicitly involve JFrame and/or swing. (Am I ignorant of some fact such as "All NetBeans java applications use JFrame", or some such?)
A pared down example of code for what I'm trying to do would be:
public class MyApp{
public static void main(String[] args){
loadMyVariables();
// do some work that changes variables' values
// during this work user clicks the 'x' box to halt execution
// I need then automatically to save the variables' new values
}
// needs to be called by the OS or GUI when execution is halted by user
public static void saveMyVariables{
// here the usual printStream stuff saves some values to a file
System.exit(0);
}
public static void loadMyVariables{
// here the usual Scanner stuff reads some values from a file
}
}
(I need help setting the tags for this, so I'm doing as instructed and asking the community.)
THANKS

Java / Swing app fails to transition to fullscreen on OS X

I'm using a JOGL FPSAnimator and Apple's FullScreenUtilies class. I implemented this some time ago, and it worked fine. Here is my code for enabling the native OS X fullscreen capability, similar to other code on SO and around the web:
String className = "com.apple.eawt.FullScreenUtilities";
String methodName = "setWindowCanFullScreen";
try {
Class<?> clazz = Class.forName(className);
Method method = clazz.getMethod(methodName,
new Class<?>[] { Window.class, boolean.class });
method.invoke(null, frame, true);
} catch ...
It also works fine in the context of a simple test program I made in an attempt to isolate the issue. I'm not sure at what point the behaviour changed - I haven't spotted anything incriminating in SVN logs. It's likely that I first implemented the feature on an earlier version of OS X, and have also upgraded JOGL version and MyDoggy which we use for docking since. However, all of these things work with fullscreen in the context of other applications.
When I press the green fullscreen button, the usual OSX fullscreen transition starts (it gets its own desktop space), but the window appears frozen from that point on.
The main AWT Event thread carries on running, and I can see that my GLEventListener.display() method is being regularly called. I've tried adding a return to the beginning of that method to eliminate the impact of my rendering code, this unsurprisingly made no difference.
For testing purposes, I added a FullScreenListener:
FullScreenUtilities.addFullScreenListenerTo(frame, new FullScreenAdapter() {
#Override
public void windowEnteringFullScreen(FullScreenEvent arg0) {
log(">>> Entering fullscreen... <<<");
}
#Override
public void windowEnteredFullScreen(FullScreenEvent arg0) {
log(">>> Entered fullscreen. <<<");
}
});
As anticipated, I get the entering fullscreen event, but not the entered one.
It's a fairly large program, but there should be a fairly small surface of things that are potentially relevant here... unfortunately I haven't managed to trace them down. Happy if anyone has any pointers.

Java wait for method to return object

I am making a library where an application can use it to capture a selection of a screen and convert it to an image, like Gyazo.
This library is not the application itself, but only the tool that returns the File or BufferedImage object to the application.
I want the application to be simple as this:
Bootstrap b = new Boostrap(new GifCapturer());
b.beginCapture(); // user selects an area
File file = b.getFile();
But how can I make the application wait till the library returns the object? as you see the beginCapture method should activate the JFrame where the user will select an area to capture.
Do I need to sleep the thread? or use listeners design?
The beginCapture method starts a jframe window, where the user is able to select an area of the screen. Once selected, the library will convert the selected area to an object and set it as a local variable. So when you will use getFile it ill return the captured image. But the thing is, i need to make sure that the image was selected before getFile call gets executed, and wait instead but im not sure how.
Sorry if the question is not detailed, im on phone.
Please let me know if you need more information.

Implement a listener, that is invoked as soon the selection is ready. Put your File file = b.getFile(); code into the listener.
The code of your JFrame would be necessary to give a more detailed answer.

I have decided to use a Listener with a own built listener class, and interface.
Create an interface which you will use to get the data, or that will get know when the listener gets called, like this in my case:
public static void main(String[] args) throws AWTException {
Bootstrap b = new Bootstrap(new GifCapturer());
b.beginCapture(new ScreenCaptureCallback() {
#Override
public void captureEnded(File file) {
System.out.println("done!");
}
});
}

java mouse capture

How do I capture the mouse in a Java application so that all mouse events (even ones that happen if the mouse is moved outside the app window) are seen by the Java app? This is like the Windows SetCapture function.

You don't; the JVM, or more specifically AWT, only generates input events when Windows sends it input events, and the JVM only registers for those events which occur within it's window.
You might be able to pull it off using JNI, but then again you might not - it will depend if you can get your hands on the information required by the underlying API. Since that's likely to be a window handle, you won't have what you need to invoke the API, even from JNI.

You have to hook the mouse at the operating system level. Windows(Swing, AWT, MFC, etc....) are only aware of mouse movements within their bounds. If you need a way to access the current position of the mouse regardless of where the mouse is on the screen, you need to write an Input Hook: Input Hooks. You can then use JNI or read the STDOUT from a win32 console application designed to use the Input Hook to forward mouse events/positions to your Java code. I use the latter method in some of my user interface test cases with success.

I needed to do that too!
I after searching the web I found that its possible to use the moveMouse in java.awt.Robot.
Basically use Robot to move the mouse into center of your frame. If user moves it: check how much and move it back to center.
No additional packets or JNI are needed for this (my demo uses JOGL and vecmath but that's for the graphics). Is it good enough? Try the demo, its here:
http://www.eit.se/hb/misc/java/examples/FirstPersonJavaProtoGame/
If the above solution is not good enough then perhaps lwjgl is what you need:
http://www.lwjgl.org/javadoc/org/lwjgl/input/Mouse.html
/Henrik Björkman

Just use the system-hook library available on gitHub https://github.com/kristian/system-hook
This only apply to windows-based systems but really simple to implement.
Sample usage
import lc.kra.system.keyboard.GlobalKeyboardHook;
import lc.kra.system.keyboard.event.GlobalKeyAdapter;
import lc.kra.system.keyboard.event.GlobalKeyEvent;
public class GlobalKeyboardExample {
private static boolean run = true;
public static void main(String[] args) {
// might throw a UnsatisfiedLinkError if the native library fails to load or a RuntimeException if hooking fails
GlobalKeyboardHook keyboardHook = new GlobalKeyboardHook();
System.out.println("Global keyboard hook successfully started, press [escape] key to shutdown.");
keyboardHook.addKeyListener(new GlobalKeyAdapter() {
#Override public void keyPressed(GlobalKeyEvent event) {
System.out.println(event);
if(event.getVirtualKeyCode()==GlobalKeyEvent.VK_ESCAPE)
run = false;
}
#Override public void keyReleased(GlobalKeyEvent event) {
System.out.println(event); }
});
try {
while(run) Thread.sleep(128);
} catch(InterruptedException e) { /* nothing to do here */ }
finally { keyboardHook.shutdownHook(); }
}
}

Problem with Java Applet

I'm new to Java Applets. I have a problem while reloading the applet. When I resize the applet window or open some other application and then come back to the applet, the contents on the screen is redrawn. Basically my paint method is getting called. I want the contents of the paint method to be called only once. How can I accomplish this? Can anyone please help me with this?
Thanks in advance.

You are misunderstanding how paint works - you have no real control over how many times it is called. What are you doing in the paint method that makes you think you only want to do it once and why is it a problem that it gets called again?
If you're worrying about flickering, then you might like to look at painting into a buffer. Code not directly related to painting should not be in the paint method. You can put other initialization logic in the applet's start method

If you're putting initialization code into the paint method, you might think about putting it into the init or start methods instead.
The phrase you'd be looking for is applet lifecycle.

I am new to java applet design and when running it i get one problem that says "no main"
here is my code:
import java.applet.*;
import java.awt.*;
public class abhidev extends Applet {
/** Initializes the applet abhidev */
public void init() {
try {
setBackground(Color.cyan);
}
catch(Exception e){
e.printStackTrace();
}
}
public void paint(Graphics g){
try{
g.drawString("this ais an applet window",10,30);
showStatus("this is astatus window");
}
catch (Exception ex) {
ex.printStackTrace();
}
}
}
The applet class name is: abhidev.java.