StackOverflow2013

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10847072
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0
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2012-06-01T08:42:59.207
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2012-06-01T08:42:59.207
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<p>You need to start QApplication in a separate QThread. This is shown in the code below. I haven't gotten it working on OS X yet, but I believe it should be doable. I need first to get a debug build made for OS X, then I'll see what's up. It's tested to work on Windows, and will probably work on X11 too. The Objective C code is for mac only, it's probably required but not sufficient yet.</p> <p>It is an entire runnable application, for a library you'd remove the <code>main()</code> function and call init, changePos and finish directly as appropriate.</p> <pre><code>#applib.pro QT += core gui TARGET = applib TEMPLATE = app !x11:!embedded:!qpa:mac { LIBS_PRIVATE += -framework Cocoa -lz OBJECTIVE_SOURCES += thread.mm } SOURCES += main.cpp </code></pre> <pre><code>//main.cpp #include <cstdlib> #include <QtCore/QThread> #include <QtCore/QMutex> #include <QtCore/QMutexLocker> #include <QtCore/QWaitCondition> #include <QtCore/QEvent> #include <QtGui/QLabel> #include <QtGui/QApplication> // // API // extern "C" { void init(int argc, char ** argv); void changePos(int x, int y); void finish(); } // demonstration code, remove from the library int main(int argc, char ** argv) { class Helper : private QThread { public: static void msleep(unsigned long ms) { QThread::msleep(ms); } }; init(argc, argv); Helper::msleep(2000); changePos(0, 0); Helper::msleep(2000); finish(); } // // IMPLEMENTATION // struct PosEvent : public QEvent { PosEvent(int x_, int y_) : QEvent(t()), x(x_), y(y_) {} const int x, y; static QEvent::Type t() { return (QEvent::Type)(QEvent::User + 0); } }; class Widget : public QLabel { public: Widget() : QLabel("Hello!") {} protected: void customEvent(QEvent * ev) { if (ev->type() == PosEvent::t()) { PosEvent * pev = static_cast<PosEvent*>(ev); move(pev->x, pev->y); } } }; class QCoreApplicationPrivate { public: static QThread * theMainThread; }; extern "C++" { Qt::HANDLE qt_application_thread_id; } class AppThread : public QThread { public: AppThread(int& argc_, char ** argv_) { Q_ASSERT(!instance); instance = this; QMutexLocker lock(&argMutex); argc = &argc_; argv = argv_; start(); wc.wait(&argMutex); } static void changePos(int x, int y) { QCoreApplication::postEvent(instance->widget, new PosEvent(x,y)); } static void finish() { instance->app->exit(); instance->wait(); delete instance; } protected: void run() { int i = 0; #ifdef Q_OS_UNIX //qDebug("%p", qt_application_thread_id); QCoreApplicationPrivate::theMainThread = QThread::currentThread(); #endif QApplication a(i, 0); app = &a; wc.wakeAll(); Widget w; widget = &w; w.show(); rc = a.exec(); } private: static AppThread * instance; QCoreApplication * app; QObject * widget; QMutex argMutex; QWaitCondition wc; int* argc; char** argv; int rc; }; AppThread * AppThread::instance = 0; bool multiThreader(); #ifndef Q_OS_MAC bool multiThreader() { return true; } #endif extern "C" void init(int argc, char ** argv) { multiThreader(); #ifdef Q_OS_MAC qDebug("DYLD_IMAGE_SUFFIX=%s", getenv("DYLD_IMAGE_SUFFIX")); #endif new AppThread(argc, argv); } extern "C" void changePos(int x, int y) { AppThread::changePos(x, y); } extern "C" void finish() { AppThread::finish(); } </code></pre> <pre><code>//thread.mm #import <Foundation/Foundation.h> @interface DeadThread : NSObject { ;; } + (void)enterMultiThreadedMode; + (void)emptyThreadMethod:(id)obj; @end @implementation DeadThread + (void)enterMultiThreadedMode { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; [NSThread detachNewThreadSelector:@selector(emptyThreadMethod:) toTarget:[DeadThread class] withObject:nil]; [pool release]; } + (void)emptyThreadMethod:(id)obj { (void)obj; } @end bool multiThreader() { [DeadThread enterMultiThreadedMode]; return [NSThread isMultiThreaded]; } </code></pre>
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1. POapp.exec() cannot call other method (static lib Qt)
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