> Hi, thanks for the detailed example. > > I guess the problem is, the async QWebPage is not exactly the same as a > background thread. I use this url for > testing http://doc.trolltech.com/qq/qq20-jambi.html > > The loading takes around 3 seconds, I feel slightly no responsive but still > fine (the page.mainFrame().contentsSize() show the size is QSize(620, > 54502)) . However, for some unknown reason, > page.mainFrame().render(painter) just hang there causing no responsive UI. > > So not running in a separate thread is ok for normal cases, but there are > cases which may cause no responsive UI..... > I may be wrong though, I do not know exactly what causes the problem for > the above URL. Viewing in a QWebView is ok without any problem though. > thanks, > canal You can use QCoreApplication.processEvents(); in the middle of some long time process to avoid unresposive UI. > > > > > ________________________________ > From: René Jahn <[email protected]> > To: [email protected] > Sent: Sat, August 21, 2010 4:31:46 PM > Subject: Re: [Qt-jambi-interest] Error: QObject used from outside its own > thread > > > Hi, > > my preferred solution: > > void thumb() { > Thumbnailer thumb = new Thumbnailer(); > thumb.load(lineEdit.text()); > } > > class Thumbnailer extends QWebPage > { > Thumbnailer() > { > loadStarted.connect(this, "loadStarted()"); > loadFinished.connect(this, "loadFinished(Boolean)"); > } > > void load(String pText) > { > mainFrame().load(new QUrl(pText)); > } > > void loadStarted() > { > System.out.println("START"); > } > > void loadFinished(Boolean pState) > { > setViewportSize(mainFrame().contentsSize()); > > QImage image = new QImage(viewportSize(), > QImage.Format.Format_ARGB32); > QPainter painter = new QPainter(image); > > mainFrame().render(painter); > painter.end(); > > // we assume that the page width is smaller than the page height > QImage thumbnail = image.scaledToWidth(218, > Qt.TransformationMode.SmoothTransformation); > thumbnail.save("d:\\thumbnail.png"); > > System.out.println ("rendering finished"); > } > > } > > The QWebPage works async. You start loading and the UI works without locks… > After the page was loaded your method will be called. > The UI works without locks… > > You don’t need a Thread. > > > To turn off thread-checks, general, call: > > System.setProperty("com.trolltech.qt.thread-check", "no"); > > But be careful when you call UI updates from threads!!! > Always use invokeLater! > > > > René > > Von:go canal [mailto:[email protected]] > Gesendet: Samstag, 21. August 2010 02:55 > An: René Jahn; [email protected] > Betreff: Re: [Qt-jambi-interest] Error: QObject used from outside its own > thread > > Thank you very much. > > I am using Windows XP, Jambi 4.5.2_01, running in Eclipse 3.6. > The program has a back/forward button, a QWebView which shows the google > web page by default. And a 'thumb' button, a url text line. Type a url, > then click 'thumb' button, it suppose to capture the web page and save the > image to a file 'thumbnail.png'. > When running the program, I can see the google web page. In > ThumbnailThread, load started signal is also captured, but no load > finished signal. Upon clicking the 'thumb' again, I saw this error > message: > QObject::startTimer: timers cannot be started from another thread > > > Source code > ======== > > Main.java > ----------- > public class Main extends QMainWindow { > > Ui_Main ui = new Ui_Main(); > > public static void main(String[] args) { > //QNetworkProxy proxy = new QNetworkProxy(ProxyType.HttpProxy, > hostname, 8080); > //QNetworkProxy.setApplicationProxy(proxy); > > QApplication.initialize(args); > > Main testMain = new Main(); > testMain.show(); > > QApplication.exec(); > } > > public Main() { > ui.setupUi(this); > } > > public Main(QWidget parent) { > super(parent); > ui.setupUi(this); > } > } > > Ui_Main.java > -------------- > public class Ui_Main implements com.trolltech.qt.QUiForm<QMainWindow> > { > public QWidget centralwidget; > public QLineEdit lineEdit; > public QWebView webView; > public QPushButton back; > public QPushButton forward; > public QPushButton thumbButton; > public QMenuBar menubar; > public QStatusBar statusbar; > > public Ui_Main() { super(); } > > public void setupUi(QMainWindow Main) > { > Main.setObjectName("Main"); > Main.resize(new QSize(800, > 367).expandedTo(Main.minimumSizeHint())); centralwidget = new > QWidget(Main); > centralwidget.setObjectName("centralwidget"); > lineEdit = new QLineEdit(centralwidget); > lineEdit.setObjectName("lineEdit"); > lineEdit.setGeometry(new QRect(100, 10, 631, 20)); > webView = new QWebView(centralwidget); > webView.setObjectName("webView"); > webView.setGeometry(new QRect(10, 40, 800, 600)); > webView.setUrl(new QUrl("http://www.google.com/";)); > back = new QPushButton(centralwidget); > back.setObjectName("back"); > back.setGeometry(new QRect(10, 10, 21, 23)); > forward = new QPushButton(centralwidget); > forward.setObjectName("forward"); > forward.setGeometry(new QRect(40, 10, 21, 23)); > thumbButton = new QPushButton(centralwidget); > thumbButton.setObjectName("thumbButton"); > thumbButton.setGeometry(new QRect(750, 10, 41, 23)); > Main.setCentralWidget(centralwidget); > menubar = new QMenuBar(Main); > menubar.setObjectName("menubar"); > menubar.setGeometry(new QRect(0, 0, 800, 21)); > Main.setMenuBar(menubar); > statusbar = new QStatusBar(Main); > statusbar.setObjectName("statusbar"); > Main.setStatusBar(statusbar); > retranslateUi(Main); > back.clicked.connect(webView, "back()"); > forward.clicked.connect(webView, "forward()"); > thumbButton.clicked.connect(this, "thumb()"); > > Main.connectSlotsByName(); > } // setupUi > > void retranslateUi(QMainWindow Main) > { > > Main.setWindowTitle(com.trolltech.qt.core.QCoreApplication.translate("Main > ", "MainWindow", null)); > > back.setText(com.trolltech.qt.core.QCoreApplication.translate("Main", > "<-", null)); > > forward.setText(com.trolltech.qt.core.QCoreApplication.translate("Main", > "->", null)); > > thumbButton.setText(com.trolltech.qt.core.QCoreApplication.translate("Main > ", "Thumb", null)); > } // retranslateUi > > > void thumb() { > ThumbnailerThread t = new ThumbnailerThread (lineEdit.text()); > QThread thread = new QThread (t); > //t.moveToThread(thread); > thread.start(); > > > } > } > > ThumbnailerThread.java > ------------------------ > public class ThumbnailerThread extends QObject implements Runnable { > public Signal0 finished = new Signal0(); > private int width = 218; > private int height = 128; > private QWebPage page; > private String url; > > public ThumbnailerThread (String url) { > this.url = url; > } > > @Override > public void run() > { > > page = new QWebPage (); > page.loadStarted.connect(this, > "loadStarted()"); > > page.loadFinished.connect(this, "render(Boolean)"); > page.mainFrame().load(new QUrl(url)); > } > > public void loadStarted () { > System.out.println ("load started"); > } > > public void render(Boolean b) { > System.out.println ("rendering now : " + > page.mainFrame().contentsSize().toString()); > // if the page is long, it may take long > time. // for example, > http://doc.trolltech.com/qq/qq20-jambi.html has a size of 620x54502 > > > > page.setViewportSize(page.mainFrame().contentsSize()); > > QImage image = new QImage(page.viewportSize(), > QImage.Format.Format_ARGB32); > QPainter painter = new QPainter(image); > > page.mainFrame().render(painter); > painter.end(); > > // we assume that the page width is smaller than the page > height > QImage thumbnail = image.scaledToWidth(width, > Qt.TransformationMode.SmoothTransformation); > thumbnail.save("thumbnail.png"); > > finished.emit(); > > System.out.println ("rendering finished"); > } > } > > > > thanks, > canal > > > > ________________________________ > > From:René Jahn <[email protected]> > To: [email protected] > Sent: Sat, August 21, 2010 1:33:06 AM > Subject: Re: [Qt-jambi-interest] Error: QObject used from outside its own > thread I tried a demo app and, it works as expected. > > Please post a running app. > > Which QTJambi version, which OS? > > > Von:go canal [mailto:[email protected]] > Gesendet: Freitag, 20. August 2010 16:13 > An: René Jahn; [email protected] > Betreff: Re: [Qt-jambi-interest] Error: QObject used from outside its own > thread > > now the problem is different: > > I have a button, when clicked, I start the thumbnail+scale thread. > nothing happen but I do capture the page load start signal; can not > capture the finish loading signal; > then I click the button again, got this error: > > QObject::startTimer: timers cannot be started from another thread > > I do not see this when first click the button. > > > thanks, > canal > > > > ________________________________ > > From:René Jahn <[email protected]> > To: [email protected] > Sent: Fri, August 20, 2010 7:41:16 PM > Subject: Re: [Qt-jambi-interest] Error: QObject used from outside its own > thread Are you behind a proxy? > > > Von:[email protected] > [mailto:[email protected]] Im Auftrag von go canal > Gesendet: Freitag, 20. August 2010 12:52 > An: Helge Fredriksen > Cc: [email protected] > Betreff: Re: [Qt-jambi-interest] Error: QObject used from outside its own > thread > > Hi, > you are right, I do not need a thread to load a page; what I wanted to do > is to capture the web page, scale it, and save as an image file. this may > takes some time and I wanted to put it into a separate thread. > > I modified a little bit (put new QWebPage() into run() method), the > exception is gone; however, I am not able to capture the loadFinished > signal (but can capture start loading signal): > > public class Thumbnailer extends QObject implements Runnable { > QWebPage page; > String url; > > public Thumbnailer (String url) { > this.url = url; > } > > public void run() { > page = new QWebPage(); /* <<<< exception if I put this is in the > constructor */ > page.loadFinished.connect (this, "render(Boolean)"); > page.mainFrame().load(new QUrl(url)); > } > > private void renbder (Boolean b) { > ..... > } > } > > thanks, > canal > > > > ________________________________ > > From:Helge Fredriksen <[email protected]> > To: go canal <[email protected]> > Cc: [email protected] > Sent: Fri, August 20, 2010 3:17:05 PM > Subject: Re: [Qt-jambi-interest] Error: QObject used from outside its own > thread > > Hello! > > Have you studied the "Hello Webkit" example in our demo application? It > seems that > no extra thread is necessary to load a page, everything happens in the > QWebView.load() > method, and it seems to take place without freezing the UI. > > Best regards, > Helge Fredriksen > > On 08/20/2010 03:40 AM, go canal wrote: > > Hi Rene, > > Thanks for your sharing. I can access the web, but I have problems > > putting it into a different thread. > > > > What I wanted to do is, upon clicking a button, the slot will create a > > new thread: > > ---- > > > > Thumbnail nail = new Thumbnail (url); > > > > QThread thread = new QThread (nailer); > > thread.start(); > > ---- > > I though this is how I should create a new Thread in Qt. > > > > The Thumbnail class is defined as: > > > > public class Thumbnailer extends QObject implements Runnable { > > > > @Override > > > > public void run() { > > page.loadFinished.connect(this, "render(Boolean)"); > > > > page.mainFrame().load(new QUrl(url)); > > } > > > > ...... > > > > } > > > > But apparently it does not work, exception at > > page.mainFrame().load(new QUrl(url)); > > > > I can not figure out what's wrong.... > > > > thanks, > > canal > > > > > > ------------------------------------------------------------------------ > > *From:* René Jahn <[email protected]> > > *To:* [email protected] > > *Sent:* Thu, August 19, 2010 3:49:11 PM > > *Subject:* Re: [Qt-jambi-interest] Error: QObject used from outside > > its own thread > > > > It should work with following code: > > /** > > > > * The <code>Main</code> class handles the web access. > > > > * > > > > * @author René Jahn > > > > */ > > > > private static final class Main extends QObject > > > > { > > > > //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > // Class members > > > > //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > /** data loaded event. */ > > > > private final > > > > QSignalEmitter.Signal1<String> loaded = new > > QSignalEmitter.Signal1<String>(); > > > > /** reload event. */ > > > > private final QSignalEmitter.Signal0 > > > > reload = new QSignalEmitter.Signal0(); > > > > /** web view. */ > > > > QWebView web; > > > > //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > // Initialization > > > > //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > /** > > > > * Creates a new instance of > > > > <code>Main</code> and starts reading the > > > > * web page. > > > > */ > > > > Main() > > > > { > > > > if > > > > (System.getProperty("http.proxyHost") != null) > > > > { > > > > try > > > > { > > > > QNetworkProxy proxy = new QNetworkProxy(ProxyType.HttpProxy); > > > > > > proxy.setHostName(System.getProperty("http.proxyHost")); > > > > > > proxy.setPort(Integer.parseInt(System.getProperty("http.proxyPort"))); > > > > > > QNetworkProxy.setApplicationProxy(proxy); > > > > } > > > > catch > > > > (Exception e) > > > > { > > > > e.printStackTrace(); > > > > } > > > > } > > > > web = new QWebView(); > > > > web.loadFinished.connect(this, "loadFinished(Boolean)"); > > > > reload.connect(this, > > > > "reloadIntern()"); > > > > } > > > > //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > // User-defined methods > > > > //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > /** > > > > * Triggers the web page reload. > > > > */ > > > > public void reload() > > > > { > > > > //needed to avoid > > > > threading problems! > > > > reload.emit(); > > > > } > > > > /** > > > > * Reloades the web page. > > > > */ > > > > @SuppressWarnings("unused") > > > > private void reloadIntern() > > > > { > > > > web.load(new > > > > QUrl("http://qtjambi.sourceforge.net";)); > > > > } > > > > /** > > > > * Forwards the html content to the > > > > signal handler. > > > > * > > > > * @param pLoaded the loaded state > > > > */ > > > > @SuppressWarnings("unused") > > > > private void loadFinished(Boolean pLoaded) > > > > { > > > > loaded.emit(web.page().mainFrame().toHtml()); > > > > } > > > > } // Main > > > > Regards, > > > > René > > > > *Von:* [email protected] > > [mailto:[email protected]] *Im Auftrag von *go > > canal *Gesendet:* Donnerstag, 19. August 2010 03:38 > > *An:* [email protected] > > *Betreff:* [Qt-jambi-interest] Error: QObject used from outside its > > own thread > > > > Hello, > > > > New to Qt Jambi, sorry if this is already been asked before. > > > > I got an exception: > > > > ----------------------------------------------------------- > > > > Exception in thread "Thread-2" QObject used from outside its own > > thread, object=QWebPage(0x17b786e8) , > > objectThread=Thread[main,5,main], currentThread=Thread[Thread-2,5,main] > > > > at > > com.trolltech.qt.GeneratorUtilities.threadCheck(GeneratorUtilities.java:5 > > 9) > > > > at com.trolltech.qt.webkit.QWebPage.mainFrame(QWebPage.java:619) > > > > at Thumbnailer.run(Thumbnailer.java:44) > > > > at java.lang.Thread.run(Thread.java:619) > > > > at com.trolltech.qt.QThread.run(QThread.java:164) > > > > ----------------------------------------------------------- > > > > Could not figure out what's wrong. Here is my code > > > > In the UI_Main : > > > > { > > > > ...... > > > > button.clicked.connect(this, "thumb()"); > > > > ...... > > > > } > > > > void thumb() { > > > > Thumbnailer nailer = new Thumbnailer (lineEdit.text()); > > > > QThread thread = new QThread (nailer); > > > > nailer.moveToThread(thread); > > > > thread.start(); > > > > } > > > > Here is the Thumbnail class (download a web page and create a > > thumbnail image): > > > > public class Thumbnailer extends QObject implements Runnable { > > > > ...... > > > > @Override > > > > public void run() { > > > > page.loadFinished.connect(this, "render(Boolean)"); > > > > page.mainFrame().load(new QUrl(url)); > > > > } > > > > ...... > > > > } > > > > What did I do wrongly ? > > > > many thanks, > > canal > > > > > > > > _______________________________________________ > > Qt-jambi-interest mailing list > > [email protected] > > http://lists.trolltech.com/mailman/listinfo/qt-jambi-interest -- Ing. José Arcángel Salazar Delgado Nettrace Av 27 #6 col. Venustiano Carranza. Boca del río, Ver. Tel. Oficina 9-27-54-78
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