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java.lang.Objectcom.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.core.QObject
com.trolltech.qt.core.QCoreApplication
public class QCoreApplication
The QCoreApplication class provides an event loop for console Qt applications.
This class is used by non-GUI applications to provide their event loop. For non-GUI application that uses Qt, there should be exactly one QCoreApplication object. For GUI applications, see QApplication.
QCoreApplication contains the main event loop, where all events from the operating system (e.g., timer and network events) and other sources are processed and dispatched. It also handles the application's initialization and finalization, as well as system-wide and application-wide settings.
The command line arguments which QCoreApplication's constructor should be called with are accessible using arguments. The event loop is started with a call to exec. Long running operations can call processEvents to keep the application responsive.
Some Qt classes, such as QString, can be used without a QCoreApplication object. However, in general, we recommend that you create a QCoreApplication or a QApplication object in your main() function as early as possible. The application will enter the event loop when exec is called. exit will not return until the event loop exits, e.g., when quit is called.
An application has an applicationDirPath and an applicationFilePath. Translation files can be added or removed using installTranslator and removeTranslator. Application strings can be translated using translate(). The QObject::tr() and QObject::trUtf8() functions are implemented in terms of translate().
The class provides a quit slot and an aboutToQuit signal.
Several static convenience functions are also provided. The QCoreApplication object is available from instance. Events can be sent or posted using sendEvent, postEvent, and sendPostedEvents. Pending events can be removed with removePostedEvents or flushed with flush. Library paths (see QLibrary) can be retrieved with libraryPaths and manipulated by setLibraryPaths, addLibraryPath, and removeLibraryPath.
Example
,
Conditions Example
Nested Class Summary | |
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static class |
QCoreApplication.Encoding
This enum type defines the 8-bit encoding of character string arguments to translate(). |
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
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QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I> |
Field Summary | |
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QSignalEmitter.Signal0 |
aboutToQuit
This signal is emitted when the application is about to quit the main event loop, e.g. when the event loop level drops to zero. |
protected static QCoreApplication |
m_instance
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QSignalEmitter.Signal1<java.lang.Integer> |
unixSignal
Compatible Slot Signatures: void mySlot(int arg__1) void mySlot() |
Constructor Summary | |
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QCoreApplication(java.lang.String[] args)
Constructs a Qt kernel application. |
Method Summary | |
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static void |
addLibraryPath(java.lang.String arg__1)
Appends arg__1 to the end of the library path list. |
static java.lang.String |
applicationDirPath()
Returns the directory that contains the application executable. |
static java.lang.String |
applicationFilePath()
Returns the file path of the application executable. |
static java.lang.String |
applicationName()
Returns the name of this application. |
static java.util.List<java.lang.String> |
arguments()
Returns the list of command-line arguments. |
static boolean |
closingDown()
Returns true if the application objects are being destroyed; otherwise returns false. |
protected void |
disposed()
Called either as the native resources that belong to the object are being cleaned up or directly before the object is finalized. |
boolean |
event(QEvent arg__1)
This function is reimplemented for internal reasons. |
static int |
exec()
Enters the main event loop and waits until exit is called. |
static void |
exit()
Equivalent to exit(0). |
static void |
exit(int retcode)
Tells the application to exit with a return code. |
static void |
flush()
Flushes the platform specific event queues. |
static QCoreApplication |
fromNativePointer(QNativePointer nativePointer)
This function returns the QCoreApplication instance pointed to by nativePointer |
static boolean |
hasPendingEvents()
This function returns true if there are pending events; otherwise returns false. |
static void |
installTranslator(QTranslator messageFile)
Adds the translation file messageFile to the list of translation files to be used for translations. |
static QCoreApplication |
instance()
Returns a pointer to the application's QCoreApplication (or QApplication) instance. |
static void |
invokeLater(java.lang.Runnable runnable)
This function will queue the runnable and invokes it later. |
static java.util.List<java.lang.String> |
libraryPaths()
Returns a list of paths that the application will search when dynamically loading libraries. |
boolean |
notify(QObject arg__1,
QEvent arg__2)
Sends arg__2 to arg__1: arg__1->event(arg__2). |
static java.lang.String |
organizationDomain()
Returns the Internet domain of the organization that wrote this application. |
static java.lang.String |
organizationName()
Returns the name of the organization that wrote this application. |
static void |
postEvent(QObject receiver,
QEvent event)
Adds the event event, with the object receiver as the receiver of the event, to an event queue and returns immediately. |
static void |
postEvent(QObject receiver,
QEvent event,
int priority)
Adds the event event, with the object receiver as the receiver of the event, to an event queue and returns immediately. |
static void |
processEvents()
Equivalent to processEvents(QEventLoop::AllEvents). |
static void |
processEvents(QEventLoop.ProcessEventsFlag... flags)
Processes all pending events for the calling thread according to the specified flags until there are no more events to process. |
static void |
processEvents(QEventLoop.ProcessEventsFlags flags)
Processes all pending events for the calling thread according to the specified flags until there are no more events to process. |
static void |
processEvents(QEventLoop.ProcessEventsFlags flags,
int maxtime)
Processes pending events for the calling thread for maxtime milliseconds or until there are no more events to process, whichever is shorter. |
static void |
quit()
Tells the application to exit with return code 0 (success). |
static void |
removeLibraryPath(java.lang.String arg__1)
Removes arg__1 from the library path list. |
static void |
removePostedEvents(QObject receiver)
Removes all events posted using postEvent for receiver. |
static void |
removePostedEvents(QObject receiver,
int eventType)
Removes all events of the given eventType that were posted using postEvent for receiver. |
static void |
removeTranslator(QTranslator messageFile)
Removes the translation file messageFile from the list of translation files used by this application. |
static boolean |
sendEvent(QObject receiver,
QEvent event)
Sends event event directly to receiver receiver, using the notify function. |
static void |
sendPostedEvents()
Dispatches all posted events, i.e. empties the event queue. |
static void |
sendPostedEvents(QObject receiver,
int event_type)
Immediately dispatches all events which have been previously queued with QCoreApplication::postEvent() and which are for the object receiver and have the event type event_type. |
static void |
setApplicationName(java.lang.String application)
Sets the name of this application to application. |
static void |
setAttribute(Qt.ApplicationAttribute attribute)
Equivalent to setAttribute(attribute, true). |
static void |
setAttribute(Qt.ApplicationAttribute attribute,
boolean on)
Sets the attribute attribute if on is true; otherwise clears the attribute. |
static void |
setLibraryPaths(java.util.List<java.lang.String> arg__1)
Sets the list of directories to search when loading libraries to arg__1. |
static void |
setOrganizationDomain(java.lang.String orgDomain)
Sets the Internet domain of the organization that wrote this application to orgDomain. |
static void |
setOrganizationName(java.lang.String orgName)
Sets the name of the organization that wrote this application to orgName. |
static boolean |
startingUp()
Returns true if an application object has not been created yet; otherwise returns false. |
static boolean |
testAttribute(Qt.ApplicationAttribute attribute)
Returns true if attribute attribute is set; otherwise returns false. |
static java.lang.String |
translate(java.lang.String context,
java.lang.String sourceText)
This is an overloaded function provided for convenience. |
static java.lang.String |
translate(java.lang.String context,
java.lang.String sourceText,
java.lang.String comment)
Returns the translation text for sourceText, by querying the installed translation files. |
static java.lang.String |
translate(java.lang.String context,
java.lang.String sourceText,
java.lang.String comment,
int n)
Returns the translation text for sourceText, by querying the installed translation files. |
Methods inherited from class com.trolltech.qt.core.QObject |
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blockSignals, childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, property, removeEventFilter, setObjectName, setParent, setProperty, signalsBlocked, startTimer, thread, timerEvent |
Methods inherited from class com.trolltech.qt.QtJambiObject |
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dispose, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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disconnect, disconnect, signalSender |
Methods inherited from class java.lang.Object |
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clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
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disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Field Detail |
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public final QSignalEmitter.Signal0 aboutToQuit
This signal is emitted when the application is about to quit the main event loop, e.g. when the event loop level drops to zero. This may happen either after a call to quit from inside the application or when the users shuts down the entire desktop session.
The signal is particularly useful if your application has to do some last-second cleanup. Note that no user interaction is possible in this state.
public final QSignalEmitter.Signal1<java.lang.Integer> unixSignal
protected static QCoreApplication m_instance
Constructor Detail |
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public QCoreApplication(java.lang.String[] args)
Method Detail |
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public boolean event(QEvent arg__1)
This function is reimplemented for internal reasons.
event
in class QObject
public boolean notify(QObject arg__1, QEvent arg__2)
Sends arg__2 to arg__1: arg__1->event(arg__2). Returns the value that is returned from the receiver's event handler.
For certain types of events (e.g. mouse and key events), the event will be propagated to the receiver's parent and so on up to the top-level object if the receiver is not interested in the event (i.e., it returns false).
There are five different ways that events can be processed; reimplementing this virtual function is just one of them. All five approaches are listed below:
public static void addLibraryPath(java.lang.String arg__1)
Appends arg__1 to the end of the library path list. If arg__1 is empty or already in the path list, the path list is not changed.
The default path list consists of a single entry, the installation directory for plugins. The default installation directory for plugins is INSTALL/plugins, where INSTALL is the directory where Qt was installed.
public static java.lang.String applicationDirPath()
Returns the directory that contains the application executable.
For example, if you have installed Qt in the C:\Trolltech\Qt directory, and you run the regexp example, this function will return "C:/Trolltech/Qt/examples/tools/regexp".
On Mac OS X this will point to the directory actually containing the executable, which may be inside of an application bundle (if the application is bundled).
Warning: On Unix, this function assumes that argv[0] contains the file name of the executable (which it normally does). It also assumes that the current directory hasn't been changed by the application.
public static java.lang.String applicationFilePath()
Returns the file path of the application executable.
For example, if you have installed Qt in the /usr/local/qt directory, and you run the regexp example, this function will return "/usr/local/qt/examples/tools/regexp/regexp".
Warning: On Unix, this function assumes that argv[0] contains the file name of the executable (which it normally does). It also assumes that the current directory hasn't been changed by the application.
public static java.lang.String applicationName()
Returns the name of this application.
The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.
public static java.util.List<java.lang.String> arguments()
Returns the list of command-line arguments.
arguments.at(0) is the program name, arguments.at(1) is the first argument, and arguments.last() is the last argument.
Calling this function is slow - you should store the result in a variable when parsing the command line.
Warning: On Unix, this list is built from the argc and argv parameters passed to the constructor in the main() function. The string-data in argv is interpreted using QString::fromLocal8Bit(); hence it is not possible to pass i.e. Japanese command line arguments on a system that runs in a latin1 locale. Most modern Unix systems do not have this limitation, as they are Unicode based.
On NT-based Windows, this limitation does not apply either.
public static boolean closingDown()
Returns true if the application objects are being destroyed; otherwise returns false.
public static int exec()
Enters the main event loop and waits until exit is called. Returns the value that was set to exit (which is 0 if exit is called via quit).
It is necessary to call this function to start event handling. The main event loop receives events from the window system and dispatches these to the application widgets.
To make your application perform idle processing (i.e. executing a special function whenever there are no pending events), use a QTimer with 0 timeout. More advanced idle processing schemes can be achieved using processEvents.
public static void exit()
Equivalent to exit(0).
public static void exit(int retcode)
Tells the application to exit with a return code.
After this function has been called, the application leaves the main event loop and returns from the call to exec. The exec function returns retcode. If the event loop is not running, this function does nothing.
By convention, a retcode of 0 means success, and any non-zero value indicates an error.
Note that unlike the C library function of the same name, this function does return to the caller -- it is event processing that stops.
public static void flush()
Flushes the platform specific event queues.
If you are doing graphical changes inside a loop that does not return to the event loop on asynchronous window systems like X11 or double buffered window systems like Mac OS X, and you want to visualize these changes immediately (e.g. Splash Screens), call this function.
public static boolean hasPendingEvents()
This function returns true if there are pending events; otherwise returns false. Pending events can be either from the window system or posted events using postEvent.
public static void installTranslator(QTranslator messageFile)
Adds the translation file messageFile to the list of translation files to be used for translations.
Multiple translation files can be installed. Translations are searched for in the last installed translation file on, back to the first installed translation file. The search stops as soon as a matching translation is found.
public static QCoreApplication instance()
Returns a pointer to the application's QCoreApplication (or QApplication) instance.
public static java.util.List<java.lang.String> libraryPaths()
Returns a list of paths that the application will search when dynamically loading libraries.
Qt provides default library paths, but they can also be set using a qt.conf file. Paths specified in this file will override default values.
This list will include the installation directory for plugins if it exists (the default installation directory for plugins is INSTALL/plugins, where INSTALL is the directory where Qt was installed). The directory of the application executable (NOT the working directory) is always added, as well as the colon separated entries of the QT_PLUGIN_PATH environment variable.
If you want to iterate over the list, you can use the foreach pseudo-keyword:
foreach (QString path, app.libraryPaths()) do_something(path);
public static java.lang.String organizationDomain()
Returns the Internet domain of the organization that wrote this application.
The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.
On Mac, QSettings uses organizationDomain as the organization if it's not an empty string; otherwise it uses organizationName. On all other platforms, QSettings uses organizationName as the organization.
public static java.lang.String organizationName()
Returns the name of the organization that wrote this application.
The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.
On Mac, QSettings uses organizationDomain as the organization if it's not an empty string; otherwise it uses organizationName. On all other platforms, QSettings uses organizationName as the organization.
public static void postEvent(QObject receiver, QEvent event, int priority)
Adds the event event, with the object receiver as the receiver of the event, to an event queue and returns immediately.
The event must be allocated on the heap since the post event queue will take ownership of the event and delete it once it has been posted. It is not safe to modify or delete the event after it has been posted.
When control returns to the main event loop, all events that are stored in the queue will be sent using the notify function.
Events are sorted in descending priority order, i.e. events with a high priority are queued before events with a lower priority. The priority can be any integer value, i.e. between INT_MAX and INT_MIN, inclusive; see Qt::EventPriority for more details. Events with equal priority will be processed in the order posted.
public static void postEvent(QObject receiver, QEvent event)
Adds the event event, with the object receiver as the receiver of the event, to an event queue and returns immediately.
The event must be allocated on the heap since the post event queue will take ownership of the event and delete it once it has been posted. It is not safe to modify or delete the event after it has been posted.
When control returns to the main event loop, all events that are stored in the queue will be sent using the notify function.
Events are processed in the order posted. For more control over the processing order, use the postEvent overload below, which takes a priority argument. This function posts all event with a Qt::NormalEventPriority.
public static void processEvents(QEventLoop.ProcessEventsFlags flags, int maxtime)
Processes pending events for the calling thread for maxtime milliseconds or until there are no more events to process, whichever is shorter.
You can call this function occasionally when you program is busy doing a long operation (e.g. copying a file).
Calling this function processes events only for the calling thread.
public static void processEvents(QEventLoop.ProcessEventsFlag... flags)
Processes all pending events for the calling thread according to the specified flags until there are no more events to process.
You can call this function occasionally when your program is busy performing a long operation (e.g. copying a file).
In event you are running a local loop which calls this function continuously, without an event loop, the DeferredDelete events will not be processed. This can affect the behaviour of widgets, e.g. QToolTip, that rely on DeferredDelete events to function properly. An alternative would be to call sendPostedEvents() from within that local loop.
Calling this function processes events only for the calling thread.
public static void processEvents()
Equivalent to processEvents(QEventLoop::AllEvents).
public static void processEvents(QEventLoop.ProcessEventsFlags flags)
Processes all pending events for the calling thread according to the specified flags until there are no more events to process.
You can call this function occasionally when your program is busy performing a long operation (e.g. copying a file).
In event you are running a local loop which calls this function continuously, without an event loop, the DeferredDelete events will not be processed. This can affect the behaviour of widgets, e.g. QToolTip, that rely on DeferredDelete events to function properly. An alternative would be to call sendPostedEvents() from within that local loop.
Calling this function processes events only for the calling thread.
public static void quit()
Tells the application to exit with return code 0 (success). Equivalent to calling QCoreApplication::exit(0).
It's common to connect the QApplication::lastWindowClosed() signal to quit, and you also often connect e.g. QAbstractButton::clicked() or signals in QAction, QMenu, or QMenuBar to it.
Example:
QPushButton *quitButton = new QPushButton("Quit"); connect(quitButton, SIGNAL(clicked()), &app, SLOT(quit()));
public static void removeLibraryPath(java.lang.String arg__1)
Removes arg__1 from the library path list. If arg__1 is empty or not in the path list, the list is not changed.
public static void removePostedEvents(QObject receiver)
Removes all events posted using postEvent for receiver.
The events are not dispatched, instead they are removed from the queue. You should never need to call this function. If you do call it, be aware that killing events may cause receiver to break one or more invariants.
public static void removePostedEvents(QObject receiver, int eventType)
Removes all events of the given eventType that were posted using postEvent for receiver.
The events are not dispatched, instead they are removed from the queue. You should never need to call this function. If you do call it, be aware that killing events may cause receiver to break one or more invariants.
If receiver is null, the events of eventType are removed for all objects. If eventType is 0, all the events are removed for receiver.
public static void removeTranslator(QTranslator messageFile)
Removes the translation file messageFile from the list of translation files used by this application. (It does not delete the translation file from the file system.)
public static boolean sendEvent(QObject receiver, QEvent event)
Sends event event directly to receiver receiver, using the notify function. Returns the value that was returned from the event handler.
The event is not deleted when the event has been sent. The normal approach is to create the event on the stack, for example:
QMouseEvent event(QEvent::MouseButtonPress, pos, 0, 0, 0); QApplication::sendEvent(mainWindow, &event);
public static void sendPostedEvents()
Dispatches all posted events, i.e. empties the event queue.
public static void sendPostedEvents(QObject receiver, int event_type)
Immediately dispatches all events which have been previously queued with QCoreApplication::postEvent() and which are for the object receiver and have the event type event_type.
Note that events from the window system are not dispatched by this function, but by processEvents.
If receiver is null, the events of event_type are sent for all objects. If event_type is 0, all the events are sent for receiver.
public static void setApplicationName(java.lang.String application)
Sets the name of this application to application.
The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.
public static void setAttribute(Qt.ApplicationAttribute attribute)
Equivalent to setAttribute(attribute, true).
public static void setAttribute(Qt.ApplicationAttribute attribute, boolean on)
Sets the attribute attribute if on is true; otherwise clears the attribute.
One of the attributes that can be set with this method is Qt::AA_ImmediateWidgetCreation. It tells Qt to create toplevel windows immediately. Normally, resources for widgets are allocated on demand to improve efficiency and minimize resource usage. Therefore, if it is important to minimize resource consumption, do not set this attribute.
public static void setLibraryPaths(java.util.List<java.lang.String> arg__1)
Sets the list of directories to search when loading libraries to arg__1. All existing paths will be deleted and the path list will consist of the paths given in arg__1.
public static void setOrganizationDomain(java.lang.String orgDomain)
Sets the Internet domain of the organization that wrote this application to orgDomain.
The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.
On Mac, QSettings uses organizationDomain as the organization if it's not an empty string; otherwise it uses organizationName. On all other platforms, QSettings uses organizationName as the organization.
public static void setOrganizationName(java.lang.String orgName)
Sets the name of the organization that wrote this application to orgName.
The value is used by the QSettings class when it is constructed using the empty constructor. This saves having to repeat this information each time a QSettings object is created.
On Mac, QSettings uses organizationDomain as the organization if it's not an empty string; otherwise it uses organizationName. On all other platforms, QSettings uses organizationName as the organization.
public static boolean startingUp()
Returns true if an application object has not been created yet; otherwise returns false.
public static boolean testAttribute(Qt.ApplicationAttribute attribute)
Returns true if attribute attribute is set; otherwise returns false.
public static QCoreApplication fromNativePointer(QNativePointer nativePointer)
nativePointer
- the QNativePointer of which object should be returned.public static java.lang.String translate(java.lang.String context, java.lang.String sourceText, java.lang.String comment)
QObject.tr() and QObject.trUtf8() provide this functionality more conveniently.
context is typically a class name (e.g., "MyDialog") and sourceText is either English text or a short identifying text.
comment is a disambiguating comment, for when the same sourceText is used in different roles within the same context. By default, it is null. encoding indicates the 8-bit encoding of character stings See the QTranslator documentation for more information about contexts and comments.
public static java.lang.String translate(java.lang.String context, java.lang.String sourceText)
public static java.lang.String translate(java.lang.String context, java.lang.String sourceText, java.lang.String comment, int n)
QObject.tr() and QObject.trUtf8() provide this functionality more conveniently.
context is typically a class name (e.g., "MyDialog") and sourceText is either English text or a short identifying text.
comment is a disambiguating comment, for when the same sourceText is used in different roles within the same context. By default, it is null. encoding indicates the 8-bit encoding of character stings See the QTranslator documentation for more information about contexts and comments.
n is used in conjunction with %n to support plural forms. See QObject.tr() for details.
protected void disposed()
disposed
in class QtJambiObject
public static void invokeLater(java.lang.Runnable runnable)
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