I'm trying to update a progressbar from another class on different thread then the main one.
but its not working for me, I dont know why
so I've created a class called BarThread.java
class BarThread extends Thread {
ClassificationV4 classObj = new ClassificationV4();
JProgressBar progressBar;
public BarThread(JProgressBar bar) {
progressBar = bar;
}
public void run() {
int minimum = 0;
int maximum = classObj.getMaximumLength();
for (int i = minimum; i < maximum; i++) {
try {
int value = progressBar.getValue();
progressBar.setValue(value + 1);
Thread.sleep(classObj.getSleepTime());
} catch (InterruptedException ignoredException) {}
}
}
}
and here I created an anonymous thread to run the progress bar inside on of my methods
//create anonymous thread
new Thread() {
public void run() {
Thread stepper = new BarThread(jProgressBar1);
stepper.start();
}
};
Any help will be appreciated.
Swing is not thread safe. You have to update your JProgressBar in the dispatcher (main) thread.
In general Swing is not thread safe. All Swing components and related classes, unless otherwise documented, must be accessed on the event dispatching thread.
You can't update UI directly from non-UI thread. Only main thread can update view/UI. If your thread want to update UI, use activity.runOnUiThread()
Official document can found here https://developer.android.com/guide/components/processes-and-threads.html#Threads
This code may help you.
class BarThread extends Thread {
ClassificationV4 classObj = new ClassificationV4();
JProgressBar progressBar;
Activity activity;
public BarThread(Activity activity, JProgressBar bar) {
this.activity = activity;
this.progressBar = bar;
}
public void run() {
int minimum = 0;
int maximum = classObj.getMaximumLength();
for (int i = minimum; i < maximum; i++) {
try {
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
int value = progressBar.getValue();
progressBar.setValue(value + 1);
}
});
Thread.sleep(classObj.getSleepTime());
} catch (InterruptedException ignoredException) {
}
}
}
}
Call from Anonymous thread
new Thread() {
public void run() {
Thread stepper = new BarThread(activity, jProgressBar1);
stepper.start();
}
};
Related
I have a thread that call's MainActivies method that sets text value of EditText but it fails.
MyRunnable is like that:
public class MyRunnable implements Runnable {
MainActivity mController;
public SoundTrigger(MainActivity pController) {
mController = pController;
}
#Override
public void run() {
for (int i = 0; i < 10000; i++) {
if(i % 100) {
mController.triggered(i);
}
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
In MainActivity class my triggered method like this:
public void triggered(int nNum) {
EditTextInstance.setText(nNum+"");
}
but it fails. All i need is printing a real time data that is created by a background thread on an edittext component.
make it like this:
#Override
public void run() {
for (int i = 0; i < 10000; i++) {
if(i % 100) {
mController.runOnUiThread(new Runnable() {
public void run() {
mController.triggered(i);
}
});
}
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Explanation: you were previously changing an UI element from a Non-UI thread and this is not good. This code should work, BUT it is still not the recommended way to approach the problem. You should use something like a AsyncTask where you have a template method for 'background' operation (non-ui thread operation) and the 'onPostExecute' which already executes on the UI thread.
another additional note: NEVER call Thread.sleep(); on the UI Thread (a.k.a. Main thread)
I am doing a project that need to get page content from web page in Java, and sometimes, I need to execute some javascript on the web page and them get the modified content. So I choose to use SWT tool. Here is part of the code:
public void run(){
Display.getDefault().asyncExec(new Runnable(){
public void run(){
display = Display.getDefault();
shell = new Shell(display,SWT.CLOSE | SWT.MIN |SWT.TITLE);
shell.setText("Web Page");
shell.setSize(1024,768);
browser = new Browser(shell, SWT.NONE);
browser.setBounds(0, 0, 1010,700);
browser.addProgressListener(new ProgressListener() {
#Override
public void completed(ProgressEvent event) {
boolean success = browser.execute(script);
if(success || script.length()==0){
model.setHtml(browser.getText());
}
shell.dispose();
}
#Override
public void changed(ProgressEvent event) {
}
});
browser.setUrl(url);
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
}
});
}
And I am calling the the run() function within a class worker which extends from SwingWorker. The worker class is defined like this:
public class worker extends SwingWorker<Object,Integer>{
private ScrapingModel model;
private ScrapingView view;
private int[] indices;
public worker(ScrapingView v, ScrapingModel m, int[] ins){
model = m;
view = v;
indices = ins;
}
#Override
protected Object doInBackground() throws Exception {
int length = indices.length;
for(int i=0;i<indices.length;i++){
int index = indices[i];
//here call the run() function, sorry I skipped some code
publish((i+1)*100/length);
}
return null;
}
#Override
protected void process(List<Integer> chunks) {
for (Integer chunk : chunks) {
view.progressBar.setValue(chunk);
}
}
}
Here is the problem: the code wthin Display.getDefault().asyncExec never executes when I call the run() function in worker class. However, if I tried to call run() outside worker class, it could be executed. Any ideas?
Instead of wrapping the Runnable in an asyncExec
Display.getDefault().asyncExec(new Runnable(){
// swt code to open shell
});
Create a new Thread
Runnable r = new Runnable(){
// swt code to open shell
}
Thread t = new Thread(r);
th.start();
I want to execude some code every second in android, but I'd like to do is in one thread (main thread). So far I have this:
locationTimer = new Timer("locationTimer", false);
locationTimer.schedule(new LocationCheckerTask(this), 0, 1000);
public class LocationCheckerTask extends TimerTask {
private GeoWatcher watcher;
public LocationCheckerTask(Context context) {
watcher = new GeoWatcher(context);
}
#Override
public void run() {
// funky stuff
}
}
Unfortunately, Timer class runs it's tasks on another thread.
Why I want to do this in a single thread?
Code in run() method will be executing really fast, so I figured I don't need another thread for it. What I want to do is to construct separate threads in run() method based on condition calculated every second. So instead of having child thread constructing another threads, I'd like to do this on the main one.
You can do this with Handler
public class Job implements Runnable{
private Handler handler;
public Job () {
handler = new Handler(Looper.getMainLooper());
loop();
}
#Override
public void run() {
// funky stuff
loop();
}
private void loop() {
handler.postDelayed(this, 1000);
}
}
use runOnUiThread(Runnable) method of Activity to run the task in UI Thread
public class LocationCheckerTask extends TimerTask {
private GeoWatcher watcher;
public LocationCheckerTask(Context context) {
watcher = new GeoWatcher(context);
}
#Override
public void run() {
runOnUiThread(new Runnable() {
#Override
public void run() {
// funky stuff
}
});
}
}
the Handler is a perfect candidate for such tasks (dont try to combine TimerTask + runOnUiThread - it is useless as it uses a Handler under the hood)
private Runnable fiveSecondRunnable = new Runnable() {
#Override
public void run() {
if (count5 < 0) {
switchT030Sec();
} else {
tvSec5.setText(""+count5);
Log.v("5sec set", "yes");
count5--;
man.postDelayed(this, 1000);
}
}
};
and start it by calling
man.post(fiveSecondRunnable);
I have problem with handling threads in my application. It creates JFrame and starts a new Thread. Last one will execute external application and update GUI. Then
I have problem to make Main class to wait for second thread to finish, but also to update GUI simultaneously.
Here's my example (shortened):
class Main {
public int status;
public Main() {
// Creating GUI etc.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JDialog id = new JDialog();
id.button.addMouseListener(new MouseListener()); // Calls generate() method
}
});
}
public void generate() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
// Make changes to GUI
}
});
GeneratorThread genTest = new GeneratorThread(this, 1, 1, 1);
genTest.start();
//while (status == 0);
System.out.println("Next step.");
}
}
And Thread class:
public class GeneratorThread extends Thread {
protected Main main;
protected int setSize, minValue, maxValue;
public GeneratorThread(Main main, int setSize, int minValue, int maxValue) {
this.main = main;
this.setSize = setSize;
this.minValue = minValue;
this.maxValue = maxValue;
}
public void run() {
// Execute program etc.
// Change GUI from main in the same time
// About 3 seconds
main.status = 1;
}
}
I'm in progress and I wanted to check how it works so far. While worked nice, but it locks Swing somehow and any changes are visible only when GeneratorThread finishes. I would like to update GUI in the real time.
I've tried join(), effects are the same. I also tried wait() (on Main), but then I got IllegalStateMonitorException.
Any hints?
Swing is a single threaded environment. That is, there is a single thread responsible for managing all the interactions and updates to the Swing UI - the Event Dispatching Thread.
Among the golden rules of Swing are...
DON'T block the EDT (Thread.sleep, Thread#join, Object#wait, block IO and/or time consuming tasks (among others) should never be called from within the EDT), doing so will stop the EDT from dispatching events and paint updates (amongst other things)
ONLY create/update Swing UI elements from within the EDT.
This raises a question...how do you "wait" for a thread?
The best way is use an Observer pattern. Basically, you provide the Thread with some kind of reference that it will call to provide notification of events, such as errors and completion...
This will require you to think very carefully about the design of your applications, as you can not rely on a simple A to B execution of your code.
For example...
public class TestThreadCallBack {
public static void main(String[] args) {
new TestThreadCallBack();
}
public TestThreadCallBack() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public interface ThreadCallBack {
public void threadCompleted(Runnable source);
public void threadFailed(Runnable source);
}
public class TestPane extends JPanel implements ThreadCallBack {
private JLabel message;
private JLabel dots;
private int count;
private Timer timer;
public TestPane() {
setLayout(new GridBagLayout());
message = new JLabel("Running background task, please wait");
dots = new JLabel(" ");
add(message);
add(dots);
timer = new Timer(250, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
count++;
if (count > 3) {
count = 0;
}
StringBuilder sb = new StringBuilder(3);
for (int index = 0; index < count; index++) {
sb.append(".");
}
for (int index = count; index < 3; index++) {
sb.append(" ");
}
dots.setText(sb.toString());
}
});
timer.setRepeats(true);
timer.setCoalesce(true);
timer.start();
Thread thread = new Thread(new BackgroundTask(this));
thread.start();
}
#Override
public void threadCompleted(Runnable source) {
timer.stop();
message.setText("Task completed successfully");
}
#Override
public void threadFailed(Runnable source) {
timer.stop();
message.setText("Task failed");
}
}
public class BackgroundTask implements Runnable {
private ThreadCallBack callBack;
public BackgroundTask(ThreadCallBack callBack) {
this.callBack = callBack;
}
#Override
public void run() {
System.out.println("Background task underway...");
try {
Thread.sleep(2000);
} catch (InterruptedException interruptedException) {
}
int result = (int) Math.round((Math.random() * 1));
if (result == 0) {
callBack.threadCompleted(this);
} else {
callBack.threadFailed(this);
}
}
}
}
Updating the UI from within a Thread other then the EDT is, well, messy. An easier solution would actually be to use a SwingWorker. This has publish/process methods that make easy to update the UI and progress methods that can be used to provide feedback about the progress of the current task.
You can use it's done method to notify interested parties when the worker has completed.
Update your GUI from within the thread using SwingUtilitied.invokeLater or, alternatively, synchronise the main variable!
http://www.vogella.com/articles/JavaConcurrency/article.html#concurrencyjava
Maybe it already suffices to make "status" volatile?
I know the subject has already been seen on many Questions and has been answered, but still, I can't get trough it.
I just want to update a progressBar while extracting some stuff of a large xml file.
I thought it was enough to have the time-consuming loop in a different thread but ?..
All I managed to get is the progressBar either not showed at all, or updated at the end, just before it's closed.
Instanced somewhere near the launch of the application, I have:
public class SomeClass {
private SomeClass () {
myXMLParser reader = new myXMLParser();
CoolStuff fromXml = reader.readTheXml();
}
}
while showing and updating a JDialog with a JProgressBar:
public class LoadingDialog extends JDialog {
private JProgressBar progressBar;
/* ... */
public void progress() {
progressBar.setValue(progressBar.getValue() + 1);
}
}
So I have this myXMLParser:
public class myXMLParser {
private LoadingDialog loadingDialog = new LoadingDialog();
public CoolStuff readTheXml() {
CoolStuff fromXml = new CoolStuff();
while(manyIterations) {
loadingDialog.progress();
fromXml.add(some() + xml() + reading());
}
return fromXml;
}
}
I have seen many things with SwingWorker and using PropertyChange events update the progressBar, but examples are always given all-in-one, with the processing and the progressbar within the same class, and with classes within classes, and since I begin in Java, I wasn't able to translate that to my situation.
Any help ?.. Any (not too obvious) advices ?
Edit: So thanks to btantlinger it worked like that:
public class SomeClass {
private SomeClass () {
myXMLParser reader = new myXMLParser();
new Thread(new Runnable() {
#Override
public void run() {
CoolStuff fromXml = reader.readTheXml();
}
}).start();
}
}
public class LoadingDialog extends JDialog {
private JProgressBar progressBar;
/* ... */
public void progress() {
progressBar.setValue(progressBar.getValue() + 1);
}
}
public class myXMLParser {
private LoadingDialog loadingDialog = new LoadingDialog();
public CoolStuff readTheXml() {
CoolStuff fromXml = new CoolStuff();
while(manyIterations) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
loadingDialog.progress();
}
});
fromXml.add(some() + xml() + reading());
}
return fromXml;
}
}
You MUST update the JProgress bar on the Swing Event Dispatch Thread. You cannot modify Swing components on any other thread.
Your only other alternative would be to set the JProgress bar "indeterminate" before you start your thread where the progress bar will just go back and forth.
E.g
progBar.setIndeterminate(true);
See the SwingWorker javadoc:
http://docs.oracle.com/javase/6/docs/api/javax/swing/SwingWorker.html
If you don't want to use the SwingWorker, another option is the SwingUtilities.invokeLater method
//inside your long running thread when you want to update a Swing component
SwingUtilities.invokeLater(new Runnable() {
public void run() {
//This will be called on the EDT
progressBar.setValue(progressBar.getValue() + 1);
}
});
In addition to the code provided by #btantlinger, I found after testing that it required an additional line of code in order to update the progress bar on the UI thread while processing. See below.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
progressBar.setValue((int)percentage);
//below code to update progress bar while running on thread
progressBar.update(progressBar.getGraphics());
}
});