Set the layers style programmatically using QGIS

Question

I have a layer of GPS points (about 60 layers) loaded inside my .qgs file. I want to set all their styles in the same manner using a .qml file without doing it one by one.

Can somebody illustrate initial Python code to do this? I'm relatively new to QGIS (2.16.1 Nodebo) since I came from ArcGIS doing simple batch processing through arcpy. In arcpy, I call the arcpy.mapping module to access my .mxd file and update my layer style through UpdateLayer function.

Answer 1

for layer in iface.mapCanvas().layers():
    layer.loadNamedStyle('path/to/qml/file')

Or if this won't work, try:

for layer in QgsMapLayerRegistry.instance().mapLayers().values():
    layer.loadNamedStyle('path/to/qml/file')

Answer 2

Not directly python solution, but there is a plugin called MultiQml that is exactly doing what you are looking for. After installing you find the plugin in menu Plugins --> MultiQml --> MultiQml. In plugin window select layers, click on Apply style ... button and search for your .qml file.