Change User preference properties via script I'm trying to make a script to change the size of the manipulator, but I get this error from console: 

Traceback (most recent call last):
File "/addon_widget_size.py", line 30, in draw
TypeError: UILayout.prop(): error with argument 1, "data" -  Function.data expected a AnyType type, not int

I have very limited skills at coding, so this error says nothing to me.

my code is:

bl_info = {
"name": "WidgetSize",
"author": "Ed-Hernandez",
"version": (1, 0),
"blender": (2, 79, 0),
"location": "View3D &gt; properties-panel",
"description": "fast change witget size",
"warning": "",
"wiki_url": "",
"category": "3D View",
}

import bpy

class WidgetSize(bpy.types.Panel):
    """creates a panel for the addon"""
    bl_label = "Widget Size"
    bl_idname = "WidgetSize"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'

    @classmethod
    def draw(self, context):
        layout = self.layout
        col = layout.column()

        row = col.row()
        row.label(text = "WitgetSize")

        row = col.row()
        row.prop(bpy.context.user_preferences.view.manipulator_size, toggle=True, text = "size")

def register():
    bpy.utils.register_class(WidgetSize)

register()
You have to pass the property name as a string as second argument:

row.prop(bpy.context.user_preferences.view, "manipulator_size",
         toggle=True, text="size")