I'm a bit desperate over here. I Have this jFrame and I need to close after I press Escape. This is easily done by using keyTyped Event. In the keyTyped event I tried to use System.exit which closes the window, but the process is still running in the task manager (and in the netbeans, even If I run from the jar file, it is still running in the task manager).
I have tried dispose, setVisible(false) along with other things but nothing seems to work.
EDIT:
Code
public Sketch(int width, int height)
{
sketch = new JFrame();
area = new JLabel();
sketch.setUndecorated(true);
sketch.setMinimumSize(new Dimension(width, height));
sketch.setSize(width, height);
area.setBounds(0, 0, width, height);
sketch.getContentPane().setLayout(null);
sketch.getContentPane().add(area);
sketch.pack();
sketch.setLocationRelativeTo(null);
sketch.setVisible(true);
sketch.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
imageBGR = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
imageGRAY = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
keyEvents();
setup();
Thread t = new Thread()
{
#Override
public void run()
{
running=true;
while(running)
draw();
}
};
t.start();
}
private void keyEvents()
{
sketch.addKeyListener(new KeyAdapter() {
#Override
public void keyTyped(KeyEvent e)
{
if(e.getKeyChar()==KeyEvent.VK_ESCAPE)
{
running=false;
System.exit(0);
}
}
});
}
NOTE: The setup function is a blank function that I override when extending this class.
EDIT2: SOLVED
I found out what I was doing wrong. It appears that in the class that I was extended this one, I was using a webcam. When I call the System.exit function the webcam led is turned off, so I thought I didn't need to properly release it, but it was in fact needed.
The default behaviour when closing your frame is not to exit the program, but just to close the window. In order to exit the program you have to do:
jframe.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
You can also do:
jFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
Your running variable needs to be declared volatile, and you need to set it to false at some point before closing.
Having said that, this code looks dangerous and bad:
Thread t = new Thread()
{
#Override
public void run()
{
running=true;
while(running)
draw();
}
};
t.start();
You've no Thread.sleep(...) within there, so it risks hogging the CPU, and as it looks like you're trying to modify Swing state off of the Swing event thread, you're in danger of intermittent thread failure. This suggests to me that you want to use a Swing Timer instead.
Note that for more complete help, consider posting a minimal code example that demonstrates your problem, an SSCCE. This will allow us to run your code and modify it and perhaps even correct it. Please read the link before replying as it supplies many important details on the SSCCE requirements.
Related
This is a bug that I tracked down yesterday and since then having a hard time to actually describe it.
The bug itself starts in the main method:
public static void main(String[] args) {
new LogManager();
new ConfigManager();
new Rendering();
new ScriptManager();
new FileManager();
new SleepManager(System.currentTimeMillis()); <-- Here it is as if the JVM just stops reading code
Since I work with eclipse I used breakpoints to locate the problematic line. And it actually reaches that last line(new SleepManager) but the method breakpoint at the SleepManager constructor is never reached:
public SleepManager(long t) {
lastCheck = t;
There is only that one constructor in the class. And in addition there is no exception whatsoever.
But eventually I managed to narrow it down to my JFramework in the Rendering Class:
public class Rendering extends JPanel implements Runnable {
private static final Log LOG = new Log(Rendering.class.getSimpleName());
private static GraphicsDevice device = GraphicsEnvironment.getLocalGraphicsEnvironment().getScreenDevices()[0];
public Rendering() {
//define basics
systemFullScreen_width = device.getDisplayMode().getWidth();
systemFullScreen_height = device.getDisplayMode().getHeight();
width = (systemFullScreen_width > 0 ? systemFullScreen_width : width);
height = (systemFullScreen_height > 0 ? systemFullScreen_height : height);
//crate framework
frame = new JFrame();
frame.addWindowListener(new FrameClose());
frame.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
frame.setSize(width, height);
frame.setUndecorated(true);
frame.setBackground(new Color(0.0f,0.0f,0.0f,0.5f));
frame.setVisible(true);
frame.setTitle(" Monitor ");
frame.setResizable(false);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setLocationRelativeTo(null);
frame.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, Collections.<AWTKeyStroke> emptySet()); //TODO remove if not needed
panel = this;
panel.setSize(width, height);
panel.setBackground(new Color(0.4f,0.4f,0.4f,0.9f));
--> frame.add(panel, 0); //here i suspect the error
panel.revalidate();
panel.setVisible(true);
//start rendering
this.start();
//frame.setAlwaysOnTop(true); //TODO enable at the end
//set input listeners
frame.addKeyListener(input);
frame.addMouseListener(input);
frame.addMouseMotionListener(input);
frame.addMouseWheelListener(input);
LOG.info("Rendering started!");
}
Ok so what I actually did accomplish in that method (since it worked when I wrote it and the transparent grey background is still working/visible) is that I try to create a half-transparent semi-fullscreen grey background to later render my own GUI element on it aka Graphics2D. Had rough time working around the fullscreen/transparency/lightweight container problem but still open for better solutions if someone has them.
So the marked line(frame.add(panel, 0);) seems to be the problem because it works when I remove the line (simple as that) and it seems to be the only line that does so.
The panel.revalidate(); was my first idea it did not help, jet i decided to keep it anyway.
Can't wrap my head around why that one line that was already done by runtime should stop another method, 200 lines beneath from being called? Any ideas?
Edit1:
Thanks to Matt who pointed out that these code lines are indeed somehow important to the subject:
public void render(Graphics2D g2d){
while(isRunning){
renderGUI(g2d); //this method does nothing jet its empty
}
frame.dispose();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
render((Graphics2D) g);
}
#Override
public void run() {
while(isRunning){
try{
frame.repaint();
Thread.sleep(5);
}catch(Exception e){
LOG.error(e);
}
}
}
Edit2:
What actually led me to the solution: Matt mentioned "EDT" what I didn't knew so I googled it and learn what the Event Dispatch Thread is. So now I knew, before this.start to start the thread gets called, the EDT actually at some point calls the paintComponent method first and enters this ugly child-code doubleloop-ception that I totally overlooked. Honestly... Shame on me. Thx Matt.
I'm new to JAVA and trying to learn some concurrency concepts.
I have a simple GUI class that pops-up a window with 1 button which I want to use for pause/continue.
Also, I have a class that extends TimerTask, it looks like below and start with the GUI:
public class process extends TimerTask {
public void run() {
while(true) { /*some repetitive macro commands.. */ }
}
}
Real question is, how can I pause the task onClick of the button and also continue onClick of the button if already paused?
I have taken a step to use a boolean to flag the button as it changes from pause to continue on each click.
But then I had to type a lot of while(button); for busy waiting inside the while()...
Do you think I can make like Thread.sleep() or something but from outside the task thread?
OLD ANSWER
Basically, there is no support for pause and resume on TimerTask, you can only cancel, check here
perhaps you might want to read about threading as that's the alternative I know of that has an interrupt and start features and then you can keep track of the progress of what you're doing to resume where it stopped.
So, I will suggest you go through this link, because you need to understand threading not just copy a code to use, there is a sample code there that will definitely solve your problem also.
Note that running an endless while loop will basically cause your program not to respond, unless the system crashes. At a certain point, the data becomes an overload and the program will overflow. This means it will fail.
.
NEW ANSWER
So, response to the new question, I was able to run a tiny little program to demonstrate how you can achieve something that looks like multithreading when working with SWING.
To rephrase your question: You want to run an indefinite task like let say we're playing a song, and then onclick of a button to pause the song, on click again should continue the song?, if so, I think below tiny program might work for you.
public class Test{
static JLabel label;
static int i = 0;
static JButton action;
static boolean x = false; //setting our x to false initialy
public static void main(String[] args) {
JFrame f=new JFrame();//creating instance of JFrame
label = new JLabel("0 Sec"); //initialized with a text
label.setBounds(130,200,100, 40);//x axis, y axis, width, height
action=new JButton("Play");//initialized with a text
action.setBounds(130,100,100, 40);//x axis, y axis, width, height
f.add(action);//adding button in JFrame
f.add(label);
action.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e){
if(x){
x = false; //Update x here
action.setText("Play");
action.revalidate();
}else{
x = true; //Update x here also
action.setText("Pause");
action.revalidate();
if(x){ //Using x here to determind whether we should start our child thread or not.
(new Thread(new Child())).start();
}
}
}
});
f.setSize(500, 700);//500 width and 700 height
f.setLayout(null);//using no layout managers
f.setVisible(true);//making the frame visible
}
}
class Child implements Runnable{
#Override
public void run() {
while (x) {
//You can put your long task here.
i++;
label.setText(i+" Secs");
label.revalidate();
try {
sleep(1000); //Sleeping time for our baby thread ..lol
} catch (InterruptedException ex) {
Logger.getLogger("No Foo");
}
}
}
}
This is my first time trying to use another thread in java, could someone tell me how to make it work please? I've read others topics about it, but I didn't find a solution.
I'd like to draw a gif in another thread (drawn at at a random position and during the duration of its animation).
The problem is that drawImage() in the second thread just doesn't do anything. My counter works well (it prints 1.. 2.. 3 ...), but no image is drawn (or I can't see it).
The condition is false at the begining, then it is true at one moment (to create only one new thread and no more), then it is false again.
if (condition) {
(new ThreadGif(this,g)).start();
}
However when I remove the condition in paintComponent(), it draws something which means that drawImage() works. So when it creates lots of new threads, every image of the gif is drawn at a random location and it starts the gif again and again (and the counter(s) still work well).
This could be fine, but I don't think creating thousands of new thread is the answer : I just need one. And also, I need just one random position for each gif, not one different for each image of the gif.
I hope I've been clear enough. Please help me understand how to make it work :) Thank you very much.
Here are simplified versions of my two classes :
ThreadGif.java :
public class ThreadGif extends Thread {
Screen screen;
Graphics g;
boolean running = true;
public ThreadGif(Screen screen, Graphics g) {
this.g = g;
this.screen = screen;
}
public void run() {
int aleaX = new Random().nextInt(300)/100;
int aleaY = new Random().nextInt(300)/100;
int compt = 1;
while (running) {
g.drawImage(new ImageIcon("res/feu.gif").getImage(), screen.tailleCase*aleaX, screen.tailleCase*aleaY, screen.tailleCase*2, screen.tailleCase*2, screen);
System.out.println("thread " + compt);
compt++;
try {
Thread.sleep(sleepTime);
} catch(InterruptedException e) {
e.printStackTrace ();
}
}
}
}
Screen.java :
public class Screen extends JPanel implements Runnable {
Thread thread = new Thread(this);
public Screen(Frame frame) {
this.frame = frame;
thread.start();
}
public void paintComponent(Graphics g) {
g.clearRect(0, 0, this.frame.getWidth(), this.frame.getHeight());
if (condition) {
(new ThreadGif(this,g)).start();
}
}
public void run() {
while (running) {
repaint();
try {
Thread.sleep(sleepTime);
} catch(InterruptedException e) {
e.printStackTrace ();
}
}
System.exit(0);
}
}
Pretty simple: you mixed two approaches up.
The paintComponent-method launches a new ThreadGif every time it's called and ThreadGif itself paints within it's thread until it's terminated, but without refreshing the screen.
These two approaches combined might either result in strange behaviour, e.g. two images painted where pieces overlay each other, or the new ThreadGif simply renders the new image every-time you repaint the screen.
Solution: Start by assigning each class specific tasks, without mixing anything up, or splitting tasks between two classes. E.g.:
ThreadGif doesn't paint anything itself, but repaints the Screen. The Screen can request the image that should be displayed from ThreadGif.
Make ThreadGif an own Component that handles it's own rendering and ommit the Screen-class from painting anything.
I am trying to draw about 100 images on the Applet. When i did that I was not able to look at an image as the process was too fast. So I added sleep function so that I can give a pause between transition from one image to another. But that worked abnormally. I could not see any pictures and I think the sleep is getting called again and again. Please help.
Here is my code:
public class Test extends Applet
{
public void init()
{
setSize(1000,1000);
}
public void make(Graphics g,int i)
{
}
public void paint(Graphics g)
{
int i=0;
for(i=0;i<100;i++)
{
if(i!=65)
{
Image img = getImage(getDocumentBase(), "abc"+i+".png");
g.drawImage(img, 0, 0, this);
try
{
Thread.sleep(1000);
}
catch(Exception exception)
{
}
}
}
}
}
Now you can see I have images from 0 to 99 and I want them on my Applet window and after an image is displayed 1 sec delay should be there. But this is not the case. Please help
sleep will freeze the EDT (Event Dispatching Thread). Since Swing is single threaded framework, anything that blocks (like sleep), prevents the EDT from running since paint is called from the context of the EDT. Don't use sleep, use Timer instead.
Another note, it's bad practice to catch an exception and not handling it. This will hide serious unexpected things that might occur in your code, at least print the error message.
Do not use Thread.sleep() as it will freeze your Swing application.
Instead you should use a javax.swing.Timer.
See the Java tutorial How to Use Swing Timers and Lesson: Concurrency in Swing for more information and examples.
What you should do
Do not draw directly on applet. Draw on a seperate panel like JPanel and add it to applet.
Dont call sleep() as it blocks the EDT. All Swing components are painted on EDT, so if it is blocked it will cause problem.
Someone also tries with a seperate thread but it is too not a good option as the thread sleeps for a time and then a repaint() mis called. It is better to use javax.swing.Timer which triggers a event after a period of time.
Try this code
public class Test extends JApplet {
int imgNo = 0;
BufferedImage bi;
JPanel p = new JPanel(){
#Override
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.white);
g.fillRect(0, 0, getWidth(), getHeight());
if(bi != null)
g.drawImage(bi, 0, 0, null);
}
};
Timer t;
#Override
public void init() {
super.init();
setSize(400,400);
t = new Timer(1000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
try{
if(imgNo != 65)
bi = ImageIO.read(new File("abc"+i+".png"));
}catch(Exception e){
e.printStackTrace();
}
imgNo++;
p.repaint();
}
});
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
p.setOpaque(true);
p.setBackground(Color.white);
setContentPane(p);
}
});
}
#Override
public void start() {
super.start();
t.start();
}
#Override
public void stop() {
super.stop();
t.stop();
}
}
There is still a disadvantage in my code as I read the images from file in the ActionListener of Timer. It is now ok for a beginner but I will recommend you to use a SwingWorker which will load the images beforehand and before even applet is started. This upgradation I will provide later
Before you read, this will be informative: Java JFrame won't show up after using .setVisible(true) after being invisible
Hello I am working on a library API that let's you capture an area of the screen, and it returns you a class that contains the ByteArrayInputStream and utility methods like createBufferedImage, createFile, etc.
Basically you create a Bootstrap instance, and pass the capturer type you want as a dependency (ScreenshotCapturer or GifCapturer):
Bootstrap b = new Bootstrap(new ScreenshotCapturer());
And the beginCapture method receives an object that implements ScreenCaptureCallback which is the callback event that the captured result will be passed to.
This is a short background.
Now when you use the beginCapture method, basically what it does is creates new instance of SelectionCamera, this is basically the component that paints the selection area you're selecting when dragging the mouse, and updates the listeners.
once created instance, it calls super.setVisible(true);
After that method gets called, the frame will show up, and also show the old painted screen for like 600-500miliseconds, I am not exactly sure, but it disappears so quickly.
Take a look at this live example:
Note use the video option, otherwise you will not see what I'm seeing as gif is too slow to show it!
http://gyazo.com/d2f0432ada37842966b42dfd87be4240
You can see after I click Screenshot again, it shows the old selected area and disappears quickly. (by the way the frame you see in the gif is not part of the app, just dummy hello world example usage).
The process of image capture.
Step 1
beginCapture gets called:
public void beginCapture(final ScreenCaptureCallback c) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
capturer.setCallback(c);
capturer.beginSelection();
}
});
}
Step 2
beginSelection gets called in the Capturer class (ScreenshotCapturer extends Capturer (abstract)
#Override
public void beginSelection() {
super.init();
this.setHotkeys();
super.getCamera().startSelection();
}
Step 3
CaptureCamera#startSelection() gets called
public void startSelection() {
super.getContentPane().removeAll();
super.getContentPane().repaint();
super.setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
this.selector = new SelectionCamera();
this.selectionMosueAdapter.updateCamera(this.selector);
this.selectionMouseMotion.updateCamera(this.selector);
super.add(this.selector);
super.setVisible(true);
super.repaint();
super.getContentPane().repaint();
}
Step 4
The user selects an area, and both mouse listener and mouse motion listens to it(Take a look at mouse motion):
#Override
public void mouseDragged(MouseEvent e) {
Point dragPoint = e.getPoint();
Point startPoint = this.selector.getStartPoint();
int x = Math.min(startPoint.x, dragPoint.x);
int y = Math.min(startPoint.y, dragPoint.y);
int width = Math.max(startPoint.x - dragPoint.x, dragPoint.x - startPoint.x);
int height = Math.max(startPoint.y - dragPoint.y, dragPoint.y - startPoint.y);
this.selector.setCameraDimension(width, height);
this.selector.setCoordinates(x, y);
this.camera.repaint(); // important
}
by the way this.selector is SelectorCamera which is the component that paints the selection area.
Step 5
CaptureCamera#endSelection() gets called, this method gets the x,y, width, height from the selection camera and passes it to the capturer class which uses Robot to get screenshot with that rectangle, and before that it removes ALL components from the content pane, and repaints everything and then sets visibility to false.
public void endSelection() {
super.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
int x = this.selector.getCameraX();
int y = this.selector.getCameraY();
int w = this.selector.getCameraWidth();
int h = this.selector.getCameraHeight();
super.getContentPane().removeAll();
super.getContentPane().repaint();
//super.repaint();
super.setVisible(false);
this.c.startCapturing(x, y, w, h);
}
Basically this is the last step, rest steps are unnecessary for the debugging as it only sends back the callback.
I really tried my best explaining the process of my application, I've tried figuring it out for 5 and half hours now, and no luck at all. Tried different ways, by creating new SelectionCamera object as you see, doesn't work.
Why is it doing this? Is it something to do with the swing core?
SelectionCamera code: https://github.com/BenBeri/WiseCapturer/blob/master/src/il/ben/wise/SelectionCamera.java
Thanks in advance.
Based on this example...
try {
final Bootstrap b = new Bootstrap(new ScreenshotCapturer());
b.beginCapture(new ScreenCaptureCallback() {
#Override
public void captureEnded(CapturedImage img) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
b.beginCapture(new ScreenCaptureCallback() {
#Override
public void captureEnded(CapturedImage img) {
System.out.println("...");
JFrame frame = new JFrame();
frame.add(new JLabel(new ImageIcon(img.getBufferedImage())));
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
});
}
});
}
});
System.out.println("Hello");
} catch (AWTException exp) {
exp.printStackTrace();
}
I won't focus on the initialise stage of the first round, I will focus on the initialisation of the second round as this is where the problem is...
b.beginCapture call's this.capturer.beginSelection();, which calls super.getCamera().startSelection(); which calls setVisible(true) (CaptureCamera been a JFrame).
This will immediately show what ever was previously displayed on the CaptureCamera. It's important to note here, that no new instances of objects were created through the process...
Now, I made a lot of changes to the base testing this, but it appears that the problem is with the restoration of the frame when it's made visible for the second time. This seems to be an issue with the transparency support of the Window as it seems to restore the last "known" state instead of repainting the window immediately...
Now, I tried clearing the selector before making the CaptureCamera invisible to no eval, as the window seems to be made invisible before the selector is painted.
The final solution I came up with was to call dispose on the CaptureCamera, which releases it's native peer and therefore destroys the old graphics context, forcing the frame to rebuild itself when it is made visible again.
"A" problem with this could be the fact that when all the windows are disposed (and the only running threads are daemon threads), the JVM will exit...
This was an issue during my testing as I was using a javax.swing.Timer to put a delay between the first and second capture process so I could see where the problem was occurring and this caused my JVM to exit (as the timer uses a daemon thread and I had no other windows open).
I got around this by creating a tiny (1x1) transparent window in the Capturer class, keep this in mind if the JVM exists gracefully for no reason ;)
Side Notes...
Now, there is an issue with SelectionCamera (which extends JPanel), it is opaque, but is using a transparent background, this is incredibly dangerous as Swing only knows how to deal with opaque or fully transparent components.
public SelectionCamera() {
super.setBackground(new Color(0, 0, 0, 0));
super.setVisible(false);
}
Should be updated to something like...
public SelectionCamera() {
setOpaque(false);
//super.setBackground(new Color(0, 0, 0, 0));
super.setVisible(false);
}
I'm also confused over the use of super.xxx, the only reason you would do this is if you had overrriden those methods and didn't want to call them at this time...In my testing, I removed all the calls to super where a method wasn't overridden in the current class (and I wasn't already in the overriden method)
Also, the paintComponent method should be calling super.paintComponent
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(new Color(0, 0, 0, 0.5f));
g.fillRect(this.x, this.y, this.width, this.height);
}
Make Frame left to be -10,000 then set visible true, add a timer 2 seconds (try lower to 25-100 milliseconds, just to give it sligth pause to invalidate content) , on timer :left to 0 . I think it works due to caching & double buffereing. Frame shows what it had in buffer, buffer points to old image due to caching/ lazy repaint.
Alternative :
Maybe a repaint or invalidate before your show would work too, and don't need to do the left -10,000. I dont work much with ui-swing, just a but years back and remember some strange things like this.