settings.py

import bpy
import os
from bpy.props import *

addon_name = os.path.basename(os.path.dirname(__file__))


def prop_changed(self, context):
    for area in bpy.context.screen.areas:
        if area.type == "TEXT_EDITOR":
            area.tag_redraw()

class CompletionProviders (bpy.types.PropertyGroup):
    use_jedi_completion = BoolProperty(default = True, name = "Use Jedi Completion",
        update = prop_changed, description = "Use the Jedi autocompletion library for python")
    use_word_completion = BoolProperty(default = True, name = "Use Word Completion",
        update = prop_changed, description = "The context box will also contain words that you already used in the file")
    use_operator_completion = BoolProperty(default = True, name = "Use Operator Completion",
        update = prop_changed, description = "Activate the autocompletion for calling operators (bpy.ops)")

class ContextBoxProperties(bpy.types.PropertyGroup):
    font_size = IntProperty(default = 12, name = "Font Size", min = 10, update = prop_changed)
    line_height = IntProperty(default = 21, name = "Line Height", min = 5, update = prop_changed)
    width = IntProperty(default = 200, name = "Width", min = 10, update = prop_changed)
    padding = IntProperty(default = 4, name = "Padding", min = 0, update = prop_changed)
    lines = IntProperty(default = 8, name = "Lines", min = 1, update = prop_changed)

class DescriptionBoxProperties(bpy.types.PropertyGroup):
    font_size = IntProperty(default = 12, name = "Font Size", min = 10, update = prop_changed)
    line_height = IntProperty(default = 21, name = "Line Height", min = 5, update = prop_changed)
    padding = IntProperty(default = 4, name = "Padding", min = 0, update = prop_changed)


class AddonPreferences(bpy.types.AddonPreferences):
    bl_idname = addon_name

    completion_providers = PointerProperty(type = CompletionProviders)
    context_box = PointerProperty(type = ContextBoxProperties)
    description_box = PointerProperty(type = DescriptionBoxProperties)
    
    debug = BoolProperty(default = False, name = "Debug",
        update = prop_changed, description = "Turn on to get some debug information from this addon")

    def draw(self, context):
        layout = self.layout

        col = layout.column()
        col.label("Completion Providers:")
        col.prop(self.completion_providers, "use_jedi_completion", "Jedi")
        col.prop(self.completion_providers, "use_word_completion", "Existing Words")
        col.prop(self.completion_providers, "use_operator_completion", "Operators")

        row = layout.row()
        col = row.column(align = True)
        col.label("Context Box")
        col.prop(self.context_box, "font_size")
        col.prop(self.context_box, "line_height")
        col.prop(self.context_box, "width")
        col.prop(self.context_box, "padding")
        col.prop(self.context_box, "lines")

        col = row.column(align = True)
        col.label("Description Box")
        col.prop(self.description_box, "font_size")
        col.prop(self.description_box, "line_height")
        col.prop(self.description_box, "padding")

        layout.prop(self, "debug")

def get_preferences():
    addon = bpy.context.user_preferences.addons.get(addon_name)
    return getattr(addon, "preferences", None)