How to create a dropdown menu in QGIS Toolbar with Python

Question

I Have a set of some QAction in my QGIS-Plugin and they are created and added to the toolbar like this

icon = QIcon(":/action1.png")
self.action1 = QAction(icon, u"Action 1", self.iface.mainWindow())
QObject.connect(self.action1, SIGNAL("triggered()"), self.someMethod)
self.iface.addToolBarIcon(self.action1)
self.iface.addPluginToMenu(u"&My Plugin", self.action1)

But now I'd like to group my Actions like in this "Select Feature" Screenshot: http://img195.imageshack.us/img195/6375/selectfeaturedropdown.png

Is this possible with Python in QGIS?

Answer 1

QToolButton

Starting from QGIS 2.0 there is iface.addToolBarWidget which lets you add a QToolButton which allows fine grained control over dropdown behavior and appearance.

self.action1 = QAction(QIcon(":/action1.png"), u"Action 1", self.iface.mainWindow())
self.action2 = QAction(QIcon(":/action2.png"), u"Action 2", self.iface.mainWindow())
self.action3 = QAction(QIcon(":/action3.png"), u"Action 3", self.iface.mainWindow())

self.popupMenu = QMenu( self.iface.mainWindow() )
self.popupMenu.addAction( self.action1 )
self.popupMenu.addAction( self.action2 )
self.popupMenu.addAction( self.action3 )

self.action1.triggered.connect( self.someMethod1 )
self.action2.triggered.connect( self.someMethod2 )
self.action3.triggered.connect( self.someMethod3 )

self.toolButton = QToolButton()

self.toolButton.setMenu( self.popupMenu )
self.toolButton.setDefaultAction( self.action1 )
self.toolButton.setPopupMode( QToolButton.InstantPopup )

self.iface.addToolBarWidget( self.toolButton )

QGIS <= 1.8

Up to QGIS 1.8, you could not do quite the same thing, because you could only add QActions to the QToolBar, but no QToolButtons ( which would let you set the PopupMode manually)

But you can get almost the same result if you assign a QMenu to your action, and to this menu you can add other actions. I did not find a possibility to change the PopupMode for this to anything else than MenuButtonPopup.

self.action1 = QAction(QIcon(":/action1.png"), u"Action 1", self.iface.mainWindow())
self.action2 = QAction(QIcon(":/action2.png"), u"Action 2", self.iface.mainWindow())
self.action3 = QAction(QIcon(":/action3.png"), u"Action 3", self.iface.mainWindow())

self.popupMenu = QMenu( self.iface.mainWindow() )
self.popupMenu.addAction( self.action2 )
self.popupMenu.addAction( self.action3 )

self.action1.triggered.connect( self.someMethod1 )
self.action2.triggered.connect( self.someMethod2 )
self.action3.triggered.connect( self.someMethod3 )

self.action1.setMenu( self.popupMenu )

self.iface.addToolBarIcon(self.action1)