Message dialogs pop up to grab the user's attention and to display important information. In this recipe, we'll create a simple information dialog.
Open the QGIS Python Console by going to the Plugins menu and selecting Python Console.
We will create a message dialog and display some text in it, as follows:
from PyQt4.QtGui import *
msg = QMessageBox()
msg.setText("This is a simple information message.")
msg.show()
Note that we are directly using the underlying Qt framework from which QGIS is built. QGIS API's objects begin with Qgs
, while Qt objects begin with just the letter Q
.
A message dialog box should also be used sparingly because it is a popup that can become annoying to the user or can get lost in the array of open windows and dialogs on a user's desktop. The preferred method for a QGIS information message is to use the QgsMessageBar() method
, which is well-documented in the PyQGIS Developer Cookbook found at http://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/communicating.html