QGIS Setting Manager

About

Easily manage the settings in your QGIS plugin.

This module can:

• manage different types of settings (bool, string, color, integer, double, stringlist)
• read and write settings both in QGIS application or in the QGIS project
• automatically set widgets of a dialog according to their corresponding setting
• automatically write settings from their corresponding widgets

You are looking at the documentation for QGIS 3. See the qgis2 branch for QGIS 2. Current version requires QGIS 3.2 minimum (otherwise projection widgets are not supported).

The main setting class

All your settings shall be saved in a single class, which will subclass SettingManager.

from qgissettingmanager import *

class MySettings(SettingManager):
    def __init__(self):
        SettingManager.__init__(self, my_plugin_name)
        self.add_setting( Bool("my_setting", Scope.Global, True) )

You may add as many settings as you want using add_setting method:

add_setting( SettingClass( name, scope, default_value, value_list: list = None, **options ) )

• SettingClass: Bool, String, Color, Integer, Double, Stringlist or Dictionary
• name: the name of the setting
• scope: Scope.Global or Scope.Project
• default_value: the default value of the setting (type must correspond)
• value_list: a list of authorized values. If specified, the setting will fall back to default_value if an unauthorized value is provided.
• options: additional options (see possible widgets)

Access the settings

Instantiate your settings class in your current class:

import MySettings
self.settings = MySettings()

The settings are easily accessed using the value and setValue methods:

myVariable = self.settings.value("myVariable")
self.settings.set_value("myVariable", False)

Remove settings

Settings can be removed from registry (local or project wise) using MySettings().remove('my_setting').

Match settings with widgets of a dialog

Quick start

You can associate a setting to a defined widget in a dialog (or a dockable window). The first condition is to name the widget as the setting name. Then, your dialog class shall subclass the SettingDialog class:

class MyDialog(QDialog, Ui_myDialog, SettingDialog):
    def __init__(self):
        settings = MySettings()
        super.__init__(self, setting_manager=settings)
        self.setupUi(self)
        self.settings = settings
        self.init_widgets()

Hence, when the dialog is shown, all widgets which are named according to a setting will be set to the corresponding value. On dialog acceptance, the settings will be set according to the value read from their widget.

To control which setting has been associated to a widget, you can print self.widget_list().

Settings’ update behavior

You can have a different behavior using SettingDialog parameters:

super.__init__(self, setting_manager=settings, mode=UpdateMode.WidgetUpdate)

mode can take the following values:

• UpdateMode.NoUpdate: settings values won’t be updated;
• UpdateMode.DialogAccept: settings values are set when the dialog is accepted (default);
• UpdateMode.WidgetUpdate: settings are set as soon as the widget is modified.

Check something before updating the settings

You can override the SettingDialog.before_accept_dialog() method to check your settings. Settings will be saved only if the method returns True.

Using showEvent

Be warned that SettingDialog implements showEvent method. Therefore, if you redefine it in your dialog class, you have to write:

def showEvent(self, e):
    settingDialog.showEvent(self, e)
    # do your own stuff

Possible widgets

The widgets are automatically detected by the manager. If the type of widget is not handled, an error is raised.

To access widget properties, get the widget after the initilization of setting widgets and set them afterwards. For instance:

class MyDialog(QDialog, Ui_myDialog, SettingDialog):
    def __init__(self):
        settings = MySettings()
        super.__init__(self, setting_manager=settings)
        self.setupUi(self)
        self.settings = settings
        self.init_widgets()

        list_table_widget: TableWidgetStringListWidget = self.setting_widget('my_list')
        list_table_widget.column = 0  # to modify the column to be checked
        list_table_widget.userdata = True  # to use UserData instead of Text
        list_table_widget.invert = True   # to invert the checking 

String

• QLineEdit
• QComboBox
  • mode additional option to define what is used to retrieve the setting. Can be ComboMode.Text or ComboMode.Data.
• QButtonGroup (the setting is set as the checked widget text in the button group)
• QgsMapLayerComboBox uses layer ID for the setting value
• QgsFileWidget

Boolean

• QCheckBox
• Any checkable widget (groupbox, etc.)

Color

• Native QGIS widgets (QgsColorButton) or any widget (label or pushbutton are recommended). For standard Qt Widgets, QGIS color button) will be used.

Additional options:

• allow_alpha (boolean) to allow transparent colors
• dialog_title (string) to set the dialog title.

Integer

• QLineEdit
• QSpinBox
• QSlider
• QComboBox (setting is set as the combo box index)

Double

• QLineEdit
• QDoubleSpinBox
• QgsScaleWidget

String list

• QListWidget (checks items having their text in the list)
• QButtonGroup (checks items having their name in the list)
• QTableWidget checks items having their text or data in the table. Properties of the widget:
  • column specifies which column is used
  • invert if True, unchecked items are saved
  • userdata if True, use the userData instead of the `text

Dictionnary

• No widgets are offered yet.

New types of widget are easily added, if one is missing, do not hesitate to ask!

Using git submodules

To use this module, you can easily copy the files and put them in your project. A more elegant way is to use git submodule. Hence, you can keep up with latest improvements. In you plugin directory, do

git submodule add https://github.com/opengisch/qgissettingmanager.git

A folder qgissettingmanager will be added to your plugin directory. However, git only references the module, and you can git pull in this folder to get the last changes.