QDesktopServices Class Reference
[QtGui module]

URL Handlers

The behavior of the openUrl() function can be customized for individual URL schemes to allow applications to override the default handling behavior for certain types of URLs.

The dispatch mechanism allows only one custom handler to be used for each URL scheme; this is set using the setUrlHandler() function. Each handler is implemented as a slot which accepts only a single QUrl argument.

The existing handlers for each scheme can be removed with the unsetUrlHandler() function. This returns the handling behavior for the given scheme to the default behavior.

This system makes it easy to implement a help system, for example. Help could be provided in labels and text browsers using help://myapplication/mytopic URLs, and by registering a handler it becomes possible to display the help text inside the application:

 class MyHelpHandler : public QObject
 {
     Q_OBJECT
 public:
     ...
 public slots:
     void showHelp(const QUrl &url);
 };

 QDesktopServices::setUrlHandler("help", helpInstance, "showHelp");

If inside the handler you decide that you can't open the requested URL, you can just call QDesktopServices::openUrl() again with the same argument, and it will try to open the URL using the appropriate mechanism for the user's desktop environment.

See also QSystemTrayIcon and QProcess.

Member Type Documentation

 QDesktopServices::openUrl(QUrl("file:///C:/Documents and Settings/All Users/Desktop", QUrl::TolerantMode));

 mailto:user@foo.com?subject=Test&body=Just a test