How to prompt for layer selection from python console in QGIS?

Question

During script development it's useful to use the QGIS python console to test the same script on different layers. Currently I've been hardcoding layer strings and just swapping out but it isn't particularly refined!

Ideally I want to prompt keyboard input or throw up a mini gui combo box.

Can anyone provide example code or signpost to some relevant documentation please. (or suggest an alternative approach)

Answer 1

You'll want to use a QgsMapLayerComboBox. If you're just after quick and dirty, you can show the combobox alone in a window using:

w=qgis.gui.QgsMapLayerComboBox()
w.show()

Then, you can retrieve the selected layer with:

w.currentLayer()

You can also filter the displayed layers by calling something like

w.setFilters( qgis.gui.QgsMapLayerProxyModel.PointLayer | qgis.gui.QgsMapLayerProxyModel.LineLayer )

and use the options shown here

Answer 2

This is the snipped code of my application (at the main program):

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.
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# Create the dialog and keep reference
reload(output_file_dialog)

dlg = OutputFile()      #create Dialog object
dlg.show()              #show Dialog object

dlg.ui.lineEdit.clear()   #clear text in lineEdit object
dlg.ui.pushButton.clicked.connect(dlg.select_output_file)   #send signal if pushButton is clicked

to produce this Dialog:

When I included only three lines of code for creating the QgsMapLayerComboBox object (see next code) and a slightly modifications in the output_file_dialog:

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.
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# Create the dialog and keep reference
reload(output_file_dialog)

dlg = OutputFile()      #create Dialog object

win = QgsMapLayerComboBox(dlg)   #create a QgsMapLayerComboBox
win.setFixedWidth(231)
win.move(150, 20)

dlg.show()                 #show Dialog object

dlg.ui.lineEdit.clear()   #clear text in lineEdit object
dlg.ui.pushButton.clicked.connect(dlg.select_output_file)   #send signal if pushButton is clicked

it changed to produce this new Dialog. It was very quick and useful.