I'm currently programming a mini game in java swing. I've got the GUI set up, and the game involves a sequence of numbers flashing up on screen and then disappearing - the user must then input the numbers again in the sequence they appeared.
When the numbers are initially displayed, I want them to display for 1-2 seconds, and then disappear, and have another number for 1-2 seconds etc.
However, I'm having issues with delaying the program whilst the number displays. I can't use Thread.sleep as it pauses the whole program with the hiding of previous numbers etc. It just doesn't work. I've tried every other suggestion I've come across, none of which have worked yet.
Anyone got anymore tips?
int delay = 5000; // delay in milliseconds
ActionListener taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent evt) { //...Perform a task... } };
Timer timer = new Timer(delay, taskPerformer);
timer.setRepeats(false);
timer.start(); // timer starts - after delay time your task gets executed
Source
You can use Thread.sleep()
The problem you having is probably because you are trying to update the UI from Swing's event dispatching thread. This is a thread that is reserved for Swing components and you should do exactly nothing in it except quick updates to the UI.
public void prog() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
label.setText("1");
}
}
try {
Thread.sleep(5000);
} catch(Exception e) { }
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
label.setText("2");
}
}
}
public static void main(String[] args) {
label = new JLabel("0");
prog();
}
JLabel label
The UI should remain responsive because of it's component interactions should be implemented in ActionListener's. But if you want to perform other work while waiting, or if the feature is contained in an ActionListener's actionPerfomed() method, you can kick off a new thread to sleep 5 seconds then update the UI. You could also perform some calculations that take 5 seconds to compute instead of sleeping without blocking the UI. The code would be:
(new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(5000);
} catch (Exception e) { }
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
label.setText("2");
}
}
}
}).start();
Related
Lets say I have a ImageView that executes at a click of a Button:
final ImageView ball = new ImageView(v.getContext());
ball.setImageResource(R.drawable.ball_1);
gameConstraintLayout.addView(ball);
When I click that button, it first off makes the ball appears , creates and runs another thread that tell itself to sleep 1000 milliseconds sleep(long millis) then removes the ball by calling ConstrainLayout.removeView(view)
Here is the full minimal code:
final ImageView ball = new ImageView(v.getContext());
currentBullet.setImageResource(R.drawable.ball_1);
gameConstraintLayout.addView(ball);
ballAppears.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
final ImageView ball = new ImageView(v.getContext());
currentBullet.setImageResource(R.drawable.ball_1);
gameConstraintLayout.addView(ball);
Thread thread = new Thread() {
#Override
public void run() {
try {
sleep(1000);
contraintLayout.removeView(ball)
} catch (InterruptedException e) {
e.printStackTrace();
}
});
}
});
Problem is;
The ball appears on screen, the other thread successfully sleeps for 1000 milliseconds, but, It crashes when It tries to remove the ball from the constraint layout in the other thread.
Logcat:
android.view.ViewRootImpl$CalledFromWrongThreadException: **Only the original thread that created a view hierarchy can touch its views**.
at android.support.constraint.ConstraintLayout.removeView(ConstraintLayout.java:645)
at com.mobilegames.***.******.GameActivity$1$1.run(GameActivity.java:51)
The code that causes the problem is:
gameConstraintLayout.removeView(ball_1);
AS it seems,I cant access the Constraint layout from the other thread but, I can still change the X and the Y of the ball.
I even tried running that piece of code in the UI theard runOnUIThread(...), but to no avail.
Here is the runONUIThread code:
shootTank.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
final ImageView currentBullet = new ImageView(v.getContext());
currentBullet.setImageResource(R.drawable.bullet_model1);
gameConstraintLayout.addView(currentBullet);
Thread thread = new Thread() {
#Override
public void run() {
try {
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
runOnUiThread(new Runnable() {
public void run() {
gameConstraintLayout.removeView(currentBullet);
}
});
}
};
thread.start();
}
});
Any possible solutions? Keep in mind that I change the X and Y's of the ball after every second.
AND YES, I did check other Questions. The answer in those ones said to simply run it on the UI thread, but of course I already tried that. If i run the sleep(long millis) into the UI thread, obliviously, the whole app would be irresponsible.
(This is not the full app; it was broken down into a much more simpler and understandable Question. I end up changing the ball's X and Y in the separate thread, but that inst what is causing the problem. Please tell me in comments if editing is necessary)
Sorry for small grammar mistakes
Use handler to perform your actions with some delay. For example:
Handler h = new Handler();
h.postDelayed(new Runnable() {
public void run() {
gameConstraintLayout.removeView(currentBullet);
}
}, 1000); // here 1000 is delay in milliseconds (1sec)
I am having an issue with a piece of my code in Java, it seems to be creating an endless loop.
public void progress(){
x = 3;
timer = new Timer(800, new ActionListener() {
public void actionPerformed(ActionEvent evt){
System.out.println(x);
x--;
if(x < 1){
UI();
timer.stop();
}
}
});
timer.start();
}
The method UI asks for input via SavitchIn, and it doesn't seem to run the line. I print before I ask for input in the UI method, and the print works just fine. When I remove this timer from my code, and keep the UI method the same, it works fine. Prints and then takes input. I've added a timer.stop() in UI method as well, and I am positive the timer is stopped, however after running the program I am forced to Reset the Virtual Machine the next time around otherwise it wont run. Any help is appreciated!
Your UI() method likely should be called on a background thread as it is likely tying up the Swing event thread (this we have to guess since you don't show it). So create a SwingWorker or a background thread and do this call in there. For more on this, please read Concurrency in Swing.
e.g.,
public void progress() {
x = 3;
timer = new Timer(800, new ActionListener() {
public void actionPerformed(ActionEvent evt) {
System.out.println(x);
x--;
if (x < 1) {
new Thread(new Runnable() {
public void run() {
UI();
}
}).start();
timer.stop();
}
}
});
timer.start();
}
I'm trying to make an JavaFX application that tracks the movement of my mouse for this im using this code in the controller class:
new Thread(new Runnable() {
#Override public void run() {
while (Main.running) {
Platform.runLater(new Runnable() {
#Override
public void run() {
try {
label.setText(MouseInfo.getPointerInfo().getLocation().toString());
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
}
}
}).start();
But it couses my application to lag big time.
How should i fix this lag problem?
Thanks i fixed it:
new Thread(new Runnable() {
#Override public void run() {
while (Main.running) {
Platform.runLater(new Runnable() {
#Override
public void run() {
label.setText(MouseInfo.getPointerInfo().getLocation().toString());
}
});
try {
Thread.sleep(200);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
What you doing is letting Javafx Application thread Thread.sleep(1000); <-wait
Any long term action you shoud put OUT of JFX-AT. And only update your ui components on it.
new Thread(()->{
while(Main.running){
Platform.runLater(()->{
//updateui component
//this is updating on FXAT
});
Thread.sleep(time)//This way you dont let JFXAT wait
}
}).start();
//Not sure if formatted and curly braces correctly.Bud you hopefully understand.Make sure you know which thread you let wait.Otherwise you wont be able to recieve events from paused jfxat.
You should put your Thread.sleep() call in your while loop and not in your Runnable, otherwise the loop keeps posting a lot of runLater tasks and those tasks stops the event thread for 1000ms after updating your mouse position
You call Thread.sleep(long) inside a Runnable that will be executed on the UI thread. If the thread is sleeping, it can't do anything else but sleep there. If you want your label to update every 1000 milliseconds, you can use the java.util.Timer class to make that happen.
I wrote a java program and made a GUI (my first one jeej).
This is my main methode:
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
ui frame = new ui();
frame.setVisible(true);
} catch (Exception e) {
ui.log("Something went wrong: " + e.getMessage());
}
}
});
}
The methode ui.log let's me write to a textArea.
My gui has one button which starts a pretty long methode which takes several minutes to complete.
In this long methode I want to be able to log to my textArea using ui.log().
It works, but It is only displayed when the methode ends and I want to see the results while the methode is running.
Both the button and the buttonEvent listener are made inside new ui();
JButton btnNewButton = new JButton("button1");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
thveryLongMethodeThatIwantToLogDuringExecution();
}
});
Does anyone knows how I can log while the methode is running?
EDIT: I think it has something to do with threads but I'm not sure. I never done something with threads.
Don't perform your work on the EDT. Use the javax.swing.SwingWorker to run time-consuming background tasks.
private class MultipleGensListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
for(int i = 0; i < 25; i++)
{
game.runSimulationOneGen();
changeGrid();
}
}
}
//this is the loop. The changeGrid method displays a game grid on a GUI but
// only the 25th iteration is visible on screen. I would like each one to be
// visible for about a half a second before the loop continues.
// I have seen some questions answered on here that are very close to what I'm asking,
// but I just don't really understand how to apply it to my program..
// thanks for any help.
If the code performed by the simulation is quick and does not consume too much CPU and time, then consider using a Swing Timer to do your looping and delay. Otherwise, you'll need to use a background thread such as can be done with a SwingWorker object.
For e.g. if using both Swing Timer and SwingWorker:
private class MultipleGensListener implements ActionListener {
protected static final int MAX_INDEX = 25;
public void actionPerformed(ActionEvent e) {
int timerDelay = 500; // ms delay
new Timer(timerDelay, new ActionListener() {
int index = 0;
public void actionPerformed(ActionEvent e) {
if (index < MAX_INDEX) { // loop only MAX_INDEX times
index++;
// create the SwingWorker and execute it
new SwingWorker<Void, Void>() {
#Override
protected Void doInBackground() throws Exception {
game.runSimulationOneGen(); // this is done in background thread.
return null;
}
#Override
protected void done() {
changeGrid(); // this is called on EDT after background thread done.
}
}.execute(); // execute the SwingWorker
} else {
((Timer) e.getSource()).stop(); // stop the timer
}
}
}).start(); // start the Swing timer
}
}
NEVER BLOCK THE GUI EVENT THREAD
you can use a timer for that and have it only fire 25 times
final Timer t = new Timer(500,null);
t.addActionListener(new ActionListener(){
int i=0;
public void actionPerformed(ActionEvent e){
game.runSimulationOneGen();//run 1 iteration per tick
changeGrid();
if(i>25){t.stop();}
i++;
}
});
t.setRepeats(true);
t.start();
btw the reason only the last iteration is shown is that gui updates (redraws) are done in a separate event, but to let another event trigger you need to return from the listener method which you didn't
the Timer I showed is a more elaborate iteration which lets other events run in between iterations allowing the gui to show the changes
check my post that shows both methods java.swing.Timer#setDelay(int)
and
correct usage of Thread.sleep(int)
java wait cursor display problem