I am following a guide that shows how to create a Pong game. There is a part, where I am supposed to create a Thread, and call a function that moves the ball.
This is the code I created:
package com.ozadari.pingpong;
public class PingPongGame extends Thread {
private Ball gameBall;
private PingPongView gameView;
public PingPongGame(Ball theBall,PingPongView mainView)
{
this.gameBall = theBall;
this.gameView = mainView;
}
#Override
public void run()
{
while(true)
{
this.gameBall.moveBall();
this.gameView.postInvalidate();
try
{
PingPongGame.sleep(5);
}
catch(InterruptedException e)
{
e.printStackTrace();
}
}
}}
The thread is called and working, but it doesn't print anything. I tried to cancel the infinte loop and make the loop run 100 times. After I wait a while, it prints to the screen as it should be after 100 runs, but it doesn't print anything in the middle.
What is the problem? How can I fix it?
Unsure from the code you've posted but anyway, you can use a handler and have it run once every second like so (change the time to what you want):
Handler handler = new Handler();
final Runnable r = new Runnable()
{
public void run()
{
//do your stuff here
handler.postDelayed(this, 1000);
}
};
handler.postDelayed(r, 1000);
http://developer.android.com/reference/android/os/Handler.html
You can also use a normal thread, and call start at the end.
Thread thread = new Thread()
{
#Override
public void run() {
try {
while(true) {
sleep(1000);
handler.post(r);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
thread.start();
Related
i'm trying to make a delay inside while loop using Thread.sleep() method . here is my code :
new Thread(new Runnable() {
#Override
public void run() {
z=0;
while (z<45){
z++;
handler.post(new Runnable() {
#Override
public void run() {
time.setText(Integer.toString(45-z));
}
});
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
this code was working and suddenly a problem occurred . it started to make a delay less than one minute , sumtimes 500 ms and sumtimes less than that
Instead if using a different thread, Thread.sleep(), Handler and while loop you can try only with Handler like this,
private int timerCount = 0;
private static Handler myHandler = new Handler();
private void runVVRunnable() {
myHandler.postDelayed(runnable, 1000);
}
private Runnable runnable = new Runnable() {
#Override
public void run() {
timerCount++;
if ((time == null)) {
return;
}
if (timerCount <= 45) {
time.setText(Integer.toString(timerCount));
runVVRunnable();
}
}
};
#Override
protected void onDestroy() {
super.onDestroy();
myHandler.removeCallbacks(runnable);
}
you can just call runVVRunnable() it will do the same process which you are doing while loop
Just a guess but when sleeping/waiting on Java thread you need to try-catch InterruptedException.
This exception is thrown when "someone" calls interrupt() on your thread.
This will cause the thread to wake up from sleep early than expected.
Check if you catch InterruptedException before your thread terminated.
Hello I'm trying to figure out a way in which my main thread return's a value every 1/10th or 1/n second for example...
public class MainGameLoop {
public static void main(String[] args) {
while (!Display.isCloseRequested()) {
//Run Game Logic
//every 1/10th second update skeletal animation
//ever 1/30th second update texture animation
}
}
I've been experimenting with seperate threads like this
public class HelloRunnable implements Runnable {
public void run() {
try{
Thread.sleep(500)
System.out.println("Hello from a thread!");
catch(Exectpion e) {
}
}
but the sleep effects my main thread's thread. If I sleep for 10 seconds, my mainthread sleeps for 10 seconds.
I've tried
Runnable z = new Runnable() {
public void run() {
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("hi");
}
};
ExecutorService executor = Executors.newCachedThreadPool();
executor.submit(z);
while (!Display.isCloseRequested()) {
//Run Game logic
}
}
This only runs once at initialization and delay's the "hi" after the specified sleep amount, alternatively this
Runnable z = new Runnable() {
public void run() {
try {
Thread.sleep(100000);
}catch(Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("hi");
}
};
ExecutorService executor = Executors.newCachedThreadPool();
while (!Display.isCloseRequested()) {
//Run Game logic
executor.submit(z);
}
}
prints out "hi" as fast as the main thread can refresh.
public class TimerDemo extends TimerTask
{
public static void main(String[] args)
{
TimerTask tasknew = new TimerDemo();
Timer timer = new Timer();
timer.scheduleAtFixedRate(tasknew, 0, 1000);
}
#Override
public void run()
{
System.out.println("once every 1000 ms");
}
}
All of the tasks run on the same thread. In the above example if run() takes longer than 1000 ms to execute, the next scheduled execution will be delayed. See the javadocs for more details. If you want multiple threads use a ScheduledThreadPoolExecutor instead.
I have a thread that is used to spin an imageview as other things happen in the background. It works great for spinning, but I've noticed as I turn it on and off (based on the spinningMain variable) the button starts to spin faster and faster and faster.
I'm unsure what the cause of this is as the thread is told to sleep every 100ms.
If it helps I also have another thread (runnable thread) which runs the main code in between, which I was wondering whether it was disrupting the thread?
The imageView update thread is:
final Thread t = new Thread() {
#Override
public void run() {
try {
while (!isInterrupted()) {
Thread.sleep(100);
runOnUiThread(new Runnable() {
#Override
public void run() {
if (spinningMain == true) {
// update TextView here!
if (spinningAngleMain >= 360) {
spinningAngleMain = 0;
} else {
spinningAngleMain += 5;
}
imageButton.setRotation(spinningAngleMain);
}
}
});
}
} catch (InterruptedException e) {
}
}
};
t.start();
And the Second thread is pretty much made as follows
new Thread(new Runnable() {
#Override
public void run() {
if (searchStateButton == true) {
//do all my stuff
}
My boolean variables are set to volatile if that helps as well.
In my GUI I have a PDF file creation operation. The operation can take up to 10-15 seconds to complete. When I start the operation, I attach a listener to it. The listener changes the cursor and disables the GUI, until the operation completes.
I would also like to add a progressbar, so the users will have a idea when it is going to complete.
Created a method startProgressBar() and called it from the start of the operation method.
See Below:
private void startSavePdfOperation() {
startProgressBar();
saveOp = new AplotSaveOperation(appReg.getString("aplot.message.SAVETOPDF"), "PDF", session);
saveOp.addOperationListener(new MyOperationListener(this) {
startProgressBar Method - See Below:
public void startProgressBar() {
Shell shell = new Shell(getShell());
shell.setSize(260, 120);
final ProgressBar bar = new ProgressBar(shell, SWT.SMOOTH);
bar.setBounds (20, 20, 200, 20);
shell.open();
final int maximum = bar.getMaximum();
new Thread(new Runnable() {
public void run() {
for (final int[] i = new int[1]; i[0] <= maximum; i[0]++) {
try {Thread.sleep (100);} catch (Throwable th) {}
if (Display.getDefault().isDisposed()) return;
Display.getDefault().asyncExec(new Runnable() {
public void run() {
if (bar.isDisposed ()) return;
bar.setSelection(i[0]);
}
});
}
}
}).start();
The code above created the ProgressBar. The issue is that the operation would end well before the progressbar indicator was close to ending.
Question: Is this because in the method I am creating a new thread and the indicator is updating according to the new thread and not the operation thread?
Question: Is it possible to create a new thread that watches the GUI thread and updates the progressbar accordingly?
Read a article suggesting using ProgressMonitorDialog with IRunnableWithProgress.
Method startProgressBar using ProgressMonitorDialog - see below:
public void startProgressBar() {
ProgressMonitorDialog dialog = new ProgressMonitorDialog(getShell());
try {
dialog.run(true, true, new IRunnableWithProgress(){
public void run(IProgressMonitor monitor) {
monitor.beginTask("Some nice progress message here ...", 100);
** getThread(); **
monitor.done();
}
});
}
catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void getThread() {
new Thread etc.. etc...
}
It seems that it will have the same issues with threading and updating as the code above.
Question: So now I am thinking can I just add or update the ProgressBar to my existing Listener
OperationListener Code - see below:
public abstract class MyOperationListener implements InterfaceAIFOperationListener {
AplotCreatePDFDialog w = null;
public MyOperationListener(AplotCreatePDFDialog win) {
w = win;
}
public void startOperation(String startMessage) {
Display.getDefault().asyncExec(new Runnable() {
public void run() {
w.getShell().setCursor(new Cursor(Display.getCurrent(), SWT.CURSOR_WAIT));
w.recursiveSetEnabled(getShell(), getShell().getEnabled());
w.getShell().setEnabled(!getShell().getEnabled());
}
});
}
public void endOperation() {
try {
endOperationImpl();
}
finally {
Display.getDefault().asyncExec(new Runnable() {
public void run() {
w.getShell().setCursor(new Cursor(Display.getCurrent(), SWT.CURSOR_ARROW));
w.recursiveSetEnabled(getShell(), true);
w.getShell().setEnabled(!getShell().getEnabled());
w.close();
}
});
}
}
abstract protected void endOperationImpl();
} // end class MyOperationListener
Thanks for any help you can give me with this.
EDIT
Baz, your answer below is exactly what the question asked, so thank you for answering.
But I am starting to think that what I am trying to do is not possible.
When my operation starts, I wanted the progress bar indicator to start and when my operation ended I wanted the indicator be at the end and the monitor would close.
I thought there might bee a way to use my listener to add the progressbar. Something like the following.
public void startOperation(String startMessage) {
Display.getDefault().asyncExec(new Runnable() {
public void run() {
->monitor.beginTask("Creating PDF File(s)", IProgressMonitor.UNKNOWN);<-
w.getShell().setCursor(new Cursor(Display.getCurrent(), SWT.CURSOR_WAIT));
w.recursiveSetEnabled(getShell(), getShell().getEnabled());
w.getShell().setEnabled(!getShell().getEnabled());
}
});
}
public void endOperation() {
try {
->monitor.worked(1);<-
endOperationImpl();
}
finally {
Display.getDefault().asyncExec(new Runnable() {
public void run() {
w.getShell().setCursor(new Cursor(Display.getCurrent(), SWT.CURSOR_ARROW));
w.recursiveSetEnabled(getShell(), true);
w.getShell().setEnabled(!getShell().getEnabled());
->monitor.done();<-
w.close();
}
});
}
}
abstract protected void endOperationImpl();
} // end class MyOperationListener
But I am starting to see that the ProgressBar has to have some sort of measurement to display the indicator correctly.
I would be happy if the indicator just went back and forth and the monitor would close at the end of the operation.
Why not use ProgressMonitorDialog?
Here is a related answer from me showing a simple example.
This is what it looks like:
If you are not sure about the workload, use this code:
monitor.beginTask("Copying files", IProgressMonitor.UNKNOWN);
It will show the idle bar while running.
Thread thread;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_yippi);
final Handler hn=new Handler();
final TextView text=(TextView)findViewById(R.id.TextView01);
final Runnable r = new Runnable()
{
public void run()
{
text.settext("hi");
}
};
thread = new Thread()
{
#Override
public void run() {
try {
while(true) {
sleep(1750);
hn.post(r);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
thread.start();
thread.stop();}
The code here. I can not stop the runnable thread. Also, thread.stop() and thread.destroy() are deprecated. Can somebody help me? And also I don't understand how to stop the thread with the thread.interrupt() method. What's wrong?
The JavaDoc for Thread.stop() lists the following article as explanation for why stop() is deprecated: http://docs.oracle.com/javase/6/docs/technotes/guides/concurrency/threadPrimitiveDeprecation.html
Most uses of stop should be replaced by code that simply modifies some variable to indicate that the target thread should stop running. The target thread should check this variable regularly, and return from its run method in an orderly fashion if the variable indicates that it is to stop running. To ensure prompt communication of the stop-request, the variable must be volatile (or access to the variable must be synchronized).
interrupt() is more suitable to stop some Thread from waiting for something, that is probably not coming anymore. If you want to end the thread, it's best to let its run() method return.
Create a boolean variable to stop the thread and use it in while(boolean) instead of while(true).
You can use Thread.interrupt() to trigger the InterruptedException within your thread. I've added code below that demonstrates the behavior. The mainThread is where your code would be and the timer Thread is just used to demonstrate delayed triggering of the interrupt.
public class Test {
public static void main(String[] args) {
final Thread mainThread = new Thread() {
#Override
public void run() {
boolean continueExecution = true;
while (continueExecution) {
try {
sleep(100);
System.out.println("Executing");
} catch (InterruptedException e) {
continueExecution = false;
}
}
}
};
mainThread.start();
Thread timer = new Thread() {
#Override
public void run() {
try {
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Stopping recurring execution");
mainThread.interrupt();
}
};
timer.start();
}
}
You can use interrupt method of Thread to try stop a thread, like below code.
May be it`s useful to you.
public class InterruptThread {
public static void main(String args[]){
Thread thread = new Thread()
{
#Override
public void run() {
try {
while(true) {
System.out.println("Thread is Runing......");
sleep(1000);
}
} catch (InterruptedException e) {
// restore interrupted status
System.out.println("Thread is interrupting");
Thread.currentThread().interrupt();
}
}
};
thread.start();
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Will Interrupt thread");
thread.interrupt();
}
}