Code du tutoriel de GeoTribu pour créer un plugin QGIS

PyQGIS_sample.py

mapCan = qgis.utils.iface.mapCanvas()
mapCan.layerCount()
>>> 1

lay = mapCan.layer(0)
print lay.name()
>>> TM_WORLD_BORDERS-0.3

lay.setLayerName("World Border")
print lay.name()
>>> World Border 

showActiveLayer.py

# run method that performs all the real work

def run(self):
    mapCanvas = self.iface.mapCanvas()
    if mapCanvas.layerCount() == 0:
        QMessageBox.warning(self.iface.mainWindow(), "Show Active Layer Plugin" , ("No active layer found"), QMessageBox.Ok)
        return layerName = ""
    for i in range(mapCanvas.layerCount()-1,-1,-1):
        layer = mapCanvas.layer(i)
        layerName += layer.name()+"\n"
    # create and show the dialog
    dlg = showActiveLayerDialog()
    dlg.ui.plainTextEdit.appendPlainText(layerName)
    dlg.show()
    result = dlg.exec_()
    
    # See if OK was pressed
    if result == 1:
        QMessageBox.warning(self.iface.mainWindow(), "Show Active Layer Plugin", ("Voulez allez quitter le plugin !"), QMessageBox.Ok) 

ui2pyqt.cmd

# compile QT to Python classes (PyQt) 
pyuic4 -o UI_isogeo_dockwidget_base.py -x isogeo_dockwidget_base.ui
pyrcc4 -o resources_rc.py resources.qrc

# changed with last plugin builder
# (source: http://anitagraser.com/2014/04/26/getting-started-writing-qgis-2-x-plugins/)
pyrcc4 -o resources.py resources.qrc

UI_showActiveLayer.py

 from PyQt4 import QtCore, QtGui
 
 class Ui_showActiveLayer(object):
     def setupUi(self, showActiveLayer):
         showActiveLayer.setObjectName("showActiveLayer")
         showActiveLayer.resize(389, 279)
         self.buttonBox = QtGui.QDialogButtonBox(showActiveLayer)
         self.buttonBox.setGeometry(QtCore.QRect(30, 240, 341, 32))
         self.buttonBox.setOrientation(QtCore.Qt.Horizontal)
         self.buttonBox.setStandardButtons(QtGui.QDialogButtonBox.Cancel|QtGui.QDialogButtonBox.Ok)
         self.buttonBox.setObjectName("buttonBox")
         self.plainTextEdit = QtGui.QPlainTextEdit(showActiveLayer)
         self.plainTextEdit.setGeometry(QtCore.QRect(10, 30, 361, 201))
         self.plainTextEdit.setObjectName("plainTextEdit")
         self.label = QtGui.QLabel(showActiveLayer)
         self.label.setGeometry(QtCore.QRect(10, 10, 181, 17))
         self.label.setObjectName("label")
         self.retranslateUi(showActiveLayer)
         QtCore.QObject.connect(self.buttonBox, QtCore.SIGNAL("accepted()"), showActiveLayer.accept)
         QtCore.QObject.connect(self.buttonBox, QtCore.SIGNAL("rejected()"), showActiveLayer.reject)
         QtCore.QMetaObject.connectSlotsByName(showActiveLayer)

  def retranslateUi(self, showActiveLayer):
      showActiveLayer.setWindowTitle(QtGui.QApplication.translate("showActiveLayer", "showActiveLayer", None, QtGui.QApplication.UnicodeUTF8))
      self.label.setText(QtGui.QApplication.translate("showActiveLayer", "Les couches actives sont :", None, QtGui.QApplication.UnicodeUTF8))

if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    showActiveLayer = QtGui.QDialog()
    ui = Ui_showActiveLayer()
    ui.setupUi(showActiveLayer)
    showActiveLayer.show()
    sys.exit(app.exec_())