QGIS Load Multiple styles on single layer at once

Question

I have a set of qml style files saved that I apply to similar layers across multiple projects. An example would be a linetype shapefile layer with about a dozen different styles; currently I have to repeat the process of adding a new style and loading the qml file for each of the different styles. Then I have to do it a few more times in that project and repeat the whole thing again in the next project.

Just trying to see if there's a way to load multiple style files on the same layer at once? Something like instead of browsing to a single qml, I could multi-select several qml files and load them at once?

Answer 1

You can load multiple styles using pyqgis script (explanations in comments):

import os
from qgis.core import QgsMapLayerStyle
from qgis.utils import iface

# set path to your styles here
qml_path = '/home/user/qml'

layer = iface.activeLayer()
style_manager = layer.styleManager()

# read valid style from layer
style = QgsMapLayerStyle()
style.readFromLayer(layer)

for qml_file in [f for f in os.listdir(qml_path)
                 if os.path.isfile(os.path.join(qml_path, f)) and
                 f.endswith('.qml')]:
    # get style name from file
    style_name = os.path.basename(qml_file).strip('.qml')
    # add style with new name
    style_manager.addStyle(style_name, style)
    # set new style as current
    style_manager.setCurrentStyle(style_name)
    # load qml to current style
    (message, success) = layer.loadNamedStyle(os.path.join(qml_path, qml_file))
    print message
    if not success:  # if style not loaded remove it
        style_manager.removeStyle(style_name)

You can run it in the QGIS python console or adapt to a processing script.

(Tested on current LTR version QGIS 2.18)

Answer 2

In case someone comes across this from post - 2023 and using 3.28.2 Firenze and above, the QGIS Dev guru's have implemented a Save Mulitple Stlyes to QML. Feature Request description on Github

An Example process:

1. Right Click> Add Style: rename to something sensible
2. Modify your symbology (this auto-saves)
3. Repeat for all styles
4. Once happy with all your stlyes. Open Symbology from your layer. Click 'Style'>Save Multiple Styles
5. In your next project, Load Styles> Navigate to your .qml file.
6. Open and Enjoy.

Answer 3

If I am understaning you correctly you just want to be able to apply geometry styles and not necessarily rules or expressions to layers quickly and easily in any project you have open?

If that is the case you could just save your styles in the symbol library using the style manager? Open up the layer style panel and click the "open library" button.