Difference between revisions of "How to Handle the Red End Key in a Qt Application"

From Qt Wiki
Jump to: navigation, search
Line 5: Line 5:
 
<code><br />Required libraries: QtGui<br />Required header files: w32std.h avkon.hrh<br />PlatSec Capabilities: None<br />Compatibility: S60 3.1 - Symbian^3
 
<code><br />Required libraries: QtGui<br />Required header files: w32std.h avkon.hrh<br />PlatSec Capabilities: None<br />Compatibility: S60 3.1 - Symbian^3
  
bool EndKeyAwareApplication::symbianEventFilter(const QSymbianEvent '''event)<br />{<br /> if (event-&gt;type()  QSymbianEvent::WindowServerEvent) &amp;#123;
+
bool EndKeyAwareApplication::symbianEventFilter(const QSymbianEvent '''event)<br />{<br /> if (event->type()  QSymbianEvent::WindowServerEvent) {
 
         //filtering window server events (TWsEvent)
 
         //filtering window server events (TWsEvent)
         if (event-&amp;gt;windowServerEvent()-&amp;gt;Type()  KAknUidValueEndKeyCloseEvent) {<br /> //filtering AVKON close event sent by end key
+
         if (event->windowServerEvent()->Type()  KAknUidValueEndKeyCloseEvent) {<br /> //filtering AVKON close event sent by end key
 
<br /> //send a Key_Hangup press/release to the focused widget<br /> //change this section if your application needs to do something else<br /> QObject''' target = focusWidget();<br /> if (target) {<br /> QEvent *event = new QKeyEvent(QEvent::KeyPress, Qt::Key_Hangup, Qt::NoModifier);<br /> postEvent(target, event);<br /> QEvent *event2 = new QKeyEvent(QEvent::KeyRelease, Qt::Key_Hangup, Qt::NoModifier);<br /> postEvent(target, event2);<br /> }<br /> //return true to prevent default handling of the event (default handler will quit app)<br /> return true;<br /> }<br /> }<br /> //allow base class to handle any other events in the default way<br /> return QApplication::symbianEventFilter(event);<br />}</code>
 
<br /> //send a Key_Hangup press/release to the focused widget<br /> //change this section if your application needs to do something else<br /> QObject''' target = focusWidget();<br /> if (target) {<br /> QEvent *event = new QKeyEvent(QEvent::KeyPress, Qt::Key_Hangup, Qt::NoModifier);<br /> postEvent(target, event);<br /> QEvent *event2 = new QKeyEvent(QEvent::KeyRelease, Qt::Key_Hangup, Qt::NoModifier);<br /> postEvent(target, event2);<br /> }<br /> //return true to prevent default handling of the event (default handler will quit app)<br /> return true;<br /> }<br /> }<br /> //allow base class to handle any other events in the default way<br /> return QApplication::symbianEventFilter(event);<br />}</code>
  

Revision as of 06:30, 25 February 2015

h1. Solution

This requires wrapping the QApplication::symbianEventFilter() function.


Required libraries: QtGui
Required header files: w32std.h avkon.hrh
PlatSec Capabilities: None
Compatibility: S60 3.1 - Symbian^3

bool EndKeyAwareApplication::symbianEventFilter(const QSymbianEvent event)
{
if (event->type() QSymbianEvent::WindowServerEvent) {

       //filtering window server events (TWsEvent)
       if (event->windowServerEvent()->Type()  KAknUidValueEndKeyCloseEvent) {
//filtering AVKON close event sent by end key


//send a Key_Hangup press/release to the focused widget
//change this section if your application needs to do something else
QObject target = focusWidget();
if (target) {
QEvent *event = new QKeyEvent(QEvent::KeyPress, Qt::Key_Hangup, Qt::NoModifier);
postEvent(target, event);
QEvent *event2 = new QKeyEvent(QEvent::KeyRelease, Qt::Key_Hangup, Qt::NoModifier);
postEvent(target, event2);
}
//return true to prevent default handling of the event (default handler will quit app)
return true;
}
}
//allow base class to handle any other events in the default way
return QApplication::symbianEventFilter(event);
}

This sample shows a simple way of handling the end key so that your application is not quit. It does not prevent the application being closed by the task switcher, and does not interfere with operation of the phone application. Pressing the red key will bring the phone application to the foreground, but leave your application running in the background.

Variants and Extensions

To save state and exit when the red key is pressed, you should instead use the QCoreApplication::aboutToQuit signal, which is cross-platform

Summary

This recipe shows how you handle the red End key in a Qt application.