Runnable updateSeekbar=new Runnable() {
#Override
public void run() {
try{
while (true) {
if (!isPlayerDead) {
Log.d("Threads", "Thread is running successfully.");
int progress=mediaPlayer.getCurrentPosition();
seekBar.setProgress(progress);
Log.d("Seekbar",seekBar.getProgress()+"");
Log.d("MediaProgress",mediaPlayer.getCurrentPosition()+"");
String s=modifyTime(mediaPlayer.getCurrentPosition() / 1000 / 60) + ":" + modifyTime((mediaPlayer.getCurrentPosition() / 1000) % 60);
progressTime.setText(s);
}
}
}
catch (Exception e){
e.printStackTrace();
}
}
};
Executor executor=new Executor() {
#Override
public void execute(Runnable command) {
Thread thread=new Thread(command);
thread.start();
}
};
executor.execute(updateSeekbar);
Actually the problem is that the thread dies before the mediaplayer can send updated position. I have made the thread in an endless while loop but still it dies. How can I make it run infinitely till the activity gets destroyed.
The thread only runs for a couple of seconds and then dies. I want it to run infinitely till the activity gets destroyed. All suggestions are welcome.
when mediaPlayer isn't in proper state and you try to call some improper method then some Exception may be thrown, and you are catching it OUTside while(true) loop. try to move try{}catch inside while(true), then your Thread will run infinitely
#Override
public void run() {
while (true) {
try{
if (!isPlayerDead) {
// current code
}
}
catch (Exception e){
e.printStackTrace();
}
SystemClock.sleep(20); // some bonus line
} // end of while
}
btw. give some rest for UI between iterations, e.g. by putting SystemClock.sleep(20); after every calculation (last line before closing bracket). you don't need so often progress refreshing, in current code it may happen even few times more often than system is capable to draw (in most often 60Hz case)
Related
tl, dr;
I have a GUI thread that creates an object of another class (the seconds class has implemented Runnable, but here we don't execute the run() method, instead, we call a normal method) and calls a method. In that method, the first thread (current thread) is called again (to show sth on the LCD), then sends some data to the Internet, and waits 3 seconds for the server response. The problem is that the information is printed after 3 seconds. I know about the stack and program counter, but I wonder if there is another option that I can do my job.
I have the main method, which runs 3 threads (for short, I just write the requisite code. Tell me to add more, if needed):
public static void main(String[] args) throws UnknownHostException, InterruptedException {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
GUI.getInstance().setVisible(true); //GUI is singleton, using swing and JFrame
} catch (Exception e) {
e.printStackTrace();
}
}
});
MQTTConnection.getInstance().tryToConnect(); //It's the connection class, which has a thread (the thread is handled by a library that keeps the connection alive. I have no threads there) and is a singleton too.
Thread t1 = new Thread(new SendDataThread()); //A thread which sends some data every 20 seconds.
t1.start();
}
And in SendDataThread, I have a function that creates some random data and sends them (using the MQTTConnection class).
This is the SendDataThread:
public class SendDataThread implements Runnable {
public void sendLog() {
boolean serverOnline = false;
StringBuilder data = new StringBuilder();
data.append(createData());
GUI.getInstance().printNeutral(data.toString()); //Prints BLACK on a `JTextPane`
if(MQTTConnection.getInstance().publishLog(MQTTConnection.getInstance().MQTT_PUBLISH_ESP_SEND_LOG, data.toString())) //This line has a 3 second timeout. If the server doesn't respond, it will return false. I've added the 3 seconds timeout too. Please continue reading.
serverOnline = true;
if(serverOnline)
GUI.getInstance().printOK("Server Submitted"); //Prints in GREEN
else
GUI.getInstance().printProblem("Check your connection!"); //Prints in RED
GUI.getInstance().printNeutral("-------------------------------------------------");
}
#Override
public void run() {
while(true) {
sendLog();
try {
Thread.sleep(20000); //sleeps 20 about seconds
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
//.....
}
And this is the 3 seconds timeout method, in MQTTConnection:
boolean publishLog(String topic, String data){
mqtt_responds = false;
publish(topic, data);
System.out.println("MQTT is connected");
long lastTime = System.currentTimeMillis();
while(System.currentTimeMillis() - lastTime < callback_timeout) {
if(mqtt_responds){
mqtt_responds = false;
System.out.println("Server submitted");
return true;
}
try {
Thread.sleep(200);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("Timeout");
return false;
}
Till now, everything work right. The problem starts where I have a button in the GUI class, which the user can manually send random logs:
JButton sendLogBtn = new JButton("Send Log");
sendLogBtn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
SendDataThread sdt = new SendDataThread();
sdt.sendLog();
}
});
sendLogBtn.setBounds(10, 331, 89, 23);
panel.add(sendLogBtn);
This button creates an object of SendDataThread and calls the sendLog() method. The issue happens here: after sendLog() is called, sendLog(), calls this GUI thread again:
--> GUI.getInstance().printNeutral(data.toString()); //Prints BLACK on a `JTextPane`
But the log is printed after 3 seconds (After the sendLog() method has finished working, the timeout!)
How can I fix this?
In the button's actionPerformed you are calling sendLog. sendLog does exactly what you said, ie reports some logs and waits about 3 seconds (assuming callback_timeout is about equal to 3000).
To fix this, you need to make sure that the 3sec blocking is not on the EDT and also to make sure that the logs are instead posted on the EDT.
As a quick workaround you can do:
sendLogBtn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
new Thread(() -> new SendDataThread().sendLog()).start();
}
});
and then, as always, post your logs in the EDT like for example:
SwingUtilities.invokeLater(() -> GUI.getInstance().printNeutral(...));
AND
SwingUtilities.invokeLater(() -> GUI.getInstance().printProblem(...));
AND
SwingUtilities.invokeLater(() -> GUI.getInstance().printOk(...));
As for the question in your comment, I don't really understand what you are asking, but I should say that (as far as I know) the EDT is a Thread where all the Swing code is (and should be) posted on for execution. This way the Swing code does not have to be synchronized, because all GUI related stuff is executed sequentially (on the EDT). AWT for example was not intended to be single threaded as far as I know. Swing is however single threaded.
I have been reading about this, and from these posts, I get that I might be a bug
SwingWorker, done() is executed before process() calls are finished
The proper way to handle exceptions thrown by the SwingWorker.doInBackground
However in my case, there is nothing that calls the done method. This is how my worker works.
public static class collectingWorker extends SwingWorker<Void, Void> {
collectingWorker(String name) {
//initialize
threadName = name;
}
#Override
public Void doInBackground() {
loop = true;
while(loop){
//Code goes here
}
return null;
}
#Override
protected void done() {
System.out.println("loop: " + loop);
System.out.println("Collecting worker DONE");
try {
get();
} catch (CancellationException x) {
System.out.println("Cancelation");
// ...
} catch (InterruptedException x) {
System.out.println("Interruption");
// ...
} catch (ExecutionException x) {
System.out.println("Execution");
System.out.println(x.getMessage());
System.out.println(x.getCause());
// ...
}
}
}
And on a separate thread, I have a counter that waits x minutes before setting loop to false. What I see is that collectingWorker done method is executed before the x minutes that it should have waited, and to make things worse, it is completely random, sometimes it works, sometimes it fails after 3 minutes, sometimes it fails after 90 minutes.
And this is what I get from the prints in the done method, as you can see, the boolean "loop" is never set to false
loop: true
Collecting worker DONE
Execution
java.util.NoSuchElementException
java.util.NoSuchElementException
Any ideas or workarounds?
The logic nested within your while(loop) is throwing a NoSuchElementException causing your entire doInBackground() method to exit prematurely.
class Test {
boolean isFirstThread = true;
private synchronized void printer(int threadNo) {
if(isFirstThread) {
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
isFirstThread = false;
System.out.println(threadNo);
}
public void starter() {
new Thread(){
#Override()
public void run() {
printer(0);
}
}.start();
new Thread(){
#Override()
public void run() {
printer(1);
}
}.start();
new Thread(){
#Override()
public void run() {
printer(2);
}
}.start();
new Thread(){
#Override()
public void run() {
printer(3);
}
}.start();
}
}
In the above code, when i call starter from main. I have created four new Threads to call a synchronized function. I know the order of execution of the threads can't be predicted. Unless they all wait for some time, so that first thread can finish and come out of the synchronized block. In which case I expect all threads to be held in a queue so i expected the answer as
0
1
2
3
But consistently(I ran the program more than 20 times) I was getting the output as
0
3
2
1
Which means that the threads are being held in a stack instead of a queue. Why is it so? Every answer in the google result says it is a queue but I am getting it as a stack. I would like to know the reason behind for holding the threads in stack(which is counter intuitive) instead of queue?
The order in which threads start is up to the OS, it is not specified in the Java Language Spec. You call start in the main thread, but when the new thread gets allocated and when it begins processing its Runnable or run method is left to the OS' scheduler to decide.
Be careful not to rely on the order in which threads happen to start.
I am new in java Android... I am trying to create two threads (named: Clean and Progress) that will run two different methods each method get the same object mix.while Clean will run a time consuming method that is part of mix's class (mix.TimeConsumingMethod();) I want Progress thread to monitor the progress of TimeConsumingMethod() by checking class variables such as mix.length and mix.framesClean
in progress I check to see mix.length > 0 if not I want Progress to wait over here my app crashes and in log CAT i get an error of:
09-20 10:37:32.773: E/AndroidRuntime(12030): java.lang.IllegalMonitorStateException: object not locked by thread before wait()
snippet of code invoking both threads:.
mix = new MixMaxMain();
progressThread = new Thread(new Runnable() {
#Override
public void run() {
Progress (mix);
}
},"Progress Thread");
CleanThread = new Thread(new Runnable() {
#Override
public void run() {
Clean (mix);
}
},"Cleaner Thread");
Log.d("STOP", "SEnding cleanThread AND progress Thread");
CleanThread.start();
progressThread.run();
snippet of Clean running time consuming method:
long time_start = SystemClock.elapsedRealtime();
mix.Run(Daudio,mu,sigSqr,c);
long time_end = SystemClock.elapsedRealtime();
snippet of Progress:
while(mix.length==0) {try {
Log.d("Progress", "Length is Zero");
Thread.sleep(1);//fails here!!
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} }
Log.d("Progress", "Clean Has Started");
int totalProgressLen = (int)(mix.length+0.7*mix.length);
while(mix.done==false)
{
try {
progressThread.wait(50);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
progress.setProgress(mix.framsClean*256/totalProgressLen );
}
You get the IllegalMonitorStateException if the thread you're calling wait on does not own the lock on the monitor you're calling it on.
To do this, you can surround the wait() call in a synchronized block. In your case, it would be something like:
synchronized(progressThread){
progressThread.wait(50);
}
There is also a way to check for this with the holdsLock(Object obj) method, which will return true only if the current thread holds the monitor lock on the specified object.
For full details, take a look at the Java Documentation on wait() for an Object.
I am just not able to figure out the cause of this issue.
Problem :
1) I am using a Thread.Sleep function to set the timer for my application.
2) Now as soon as user enter the webPage the timer starts, if user clicks any link the timer(thread) is stopped and then new timer starts.
3) If their is no activity for say 3 seconds, timer ends and with it workflow associated with the webpage ends too.
Code :
DownloadSummariesPage.java
public DownloadSummariesPage(){
abc = new SimpleThread(this);
Link<Void> link = new Link<Void>("downloadSummaryLink") {
public void onClick() {
boolean threadStatus = abc.checkStatus();
if (threadStatus) {
abc.interrupt();
abc.stop();
abc = new SimpleThread(DownloadSummariesPage.this);
abc.start();
}
else
{
LOG.debug("thread is dead now");
endWorkflow();
LOG.debug("ending the workflow");
setResponsePage(MenuPage.class);
}
}
};
abc.start();
}
public void endWorkflow() {
abc.interrupt();
abc.stop();
boolean downloadReport = false;
LOG.debug("before action 201 inside endworkflow");
Map<String, Serializable> inputs = new HashMap<String, Serializable>();
inputs.put("downloadReport", downloadReport);
try {
wf.doAction(id, 201, inputs);//do not worry about this its for workflow
String empty = "";
populateDownloadReportDatabase(empty);
setResponsePage(MenuPage.class);
} catch (Exception e) {
LOG.debug("Exception while performing 201 workflow, getControlCancel "
+ e);
}
}
}
My next class which creates thread is
SimpleThread.java
class SimpleThread extends Thread {
private static final Logger LOG = Logger.getLogger(SimpleThread.class);
boolean stillActive = true;
DownloadSummariesPage dsp;
SimpleThread(DownloadSummariesPage dp) {
this.dsp = dp;
}
public void run() {
// 5sec timer
LOG.debug("inside run method");
try {
Thread.sleep(3000);
stillActive = false;
} catch (InterruptedException e) {
LOG.debug("Exception in thread " + e);
e.printStackTrace();
}
LOG.debug("before endworkflow");
dsp.endWorkflow();//so this is what i actually want to do...
LOG.debug("at the end of simplethread");
}
public boolean checkStatus() {
return stillActive;
}
}
Cases :
1) Whats Happening : User logs in thread sleeps, user click a link thread stops and creates a new one if user again click it happens again and now if user do not do anything for 3 seconds, stillAlive variable in SimpleThread class is set to false and when now user click its ends the workflow perfectly...
2) What i want : if user logs in thread starts, and if their is no activity by the user stillAlive variable is set to false and dsp.endWorkflow(); statement now should end the workflow. right ? but it just stops after reaching inside the endWorkflow() function and do not actually end the workflow...
Hope you get this, I tried my best to make it understandable. Thanks for your time..
I appreciate any help..
So there are some strange things here.
first assume the thread sleep without any interruption for 3 sec, so it will call the dsp.endWorkflow() where you call it again from the onClick method.
second the stillAlive flag should be volatile
boolean volatile stillActive = true;
The possible error/bug would raises by this section.
if (threadStatus) {
abc.interrupt();
abc.stop();// you cannot get to this like just after interrupt, maybe thread abc goes first
abc = new SimpleThread(DownloadSummariesPage.this);
abc.start();
}
because assume when thread is sleeping you interrupt it, then stop it, but this is possible that thread finishes it's work just after you interrupt it (before you stop it). so this is better to just stop it, or return when thread reached the catch.
try {
Thread.sleep(3000);
stillActive = false;
} catch (InterruptedException e) {
LOG.debug("Exception in thread " + e);
e.printStackTrace();
return;//////give up the rest work. so you don't need to call the stop too.
}
And the error is here
assume that user don't click the cancel, or new download, and thread just finishes its sleeping and call the dsp.endWorkflow(), so what is going on this method?
public void endWorkflow() {
abc.interrupt();
abc.stop();//error here!
boolean downloadReport = false;//this is unreachable
}
Just look, you are calling this method by abc thread, and the error is that you are killing the thread just inside the method, before you set the downloadReport to false. so it may would be like this.
public void endWorkflow() {
boolean downloadReport = false;//this is unreachable
abc.interrupt();
abc.stop();//error here!
}
I hope I could some help.