How do you import a .py file so that it runs when a button is clicked in kivy? It says that the module name is not defined

Question

So, I have kivy code in one file and I'm trying to link one of my buttons to an external python file (I think the word is module?). I'm trying to import this file but I get the error "NameError: name 'Aruco' is not defined"

I'm trying to import this file but I get the error "NameError: name 'Aruco' is not defined" Aruco.py is the name of the module that I want to import.

main.py

import kivy
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.properties import ObjectProperty
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang.builder import Builder
import sqlite3
import Aruco

class MainWindow(Screen):
    pass

class InfoWindow(Screen):
    pass

class LocaliseWindow(Screen):
    pass

class WindowManager(ScreenManager):
    pass

kv = Builder.load_string("""
WindowManager:
    MainWindow:
    LocaliseWindow:
    InfoWindow


<MainWindow>:
    name: "main"
    GridLayout:
        padding: 50
        spacing: 20
        cols:1
        size: root.width, root.height
        Camera:
            id: camera
            play: True
        GridLayout:
            cols:2
            spacing: 20
            Button:
                text: "Localise"
                on_release: 
                    app.root.current = "localise"
                    root.manager.transition.direction = "left"
                background_normal: ""
                background_color: "#05b4ff"
            Button:
                text: "Info"
                on_press:
                    app.root.current = "info"
                    root.manager.transition.direction = "left"
                background_normal: ""
                background_color: "#05b4ff"

<LocaliseWIndow>:
    name: "localise"
    BoxLayout:
        padding: 50
        spacing: 10
        orientation: "vertical"
        Label:
            id: choose_destination
            font_size: 24
            text: "Choose Destination"
        Button:
            id:Maths
            text: "Maths"
            on_press: Aruco.detect()
            background_normal: ""
            background_color: "#05b4ff"
        Button:
            id: English
            text: "English"
            on_press: app.submit()
            background_normal: ""
            background_color: "#05b4ff"
        Button:
            id: Science
            text: "Science"
            on_press: app.submit()
            background_normal: ""
            background_color: "#05b4ff"
        Button:
            id: Humanities
            text: "Humanities"
            on_press: app.submit()
            background_normal: ""
            background_color: "#05b4ff"
        Button:
            id: Office
            text: "Office"
            on_press: app.submit()
            background_normal: ""
            background_color: "#05b4ff"
        Button:
            id: Restroom
            text: "Restroom"
            on_press: app.submit()
            background_normal: ""
            background_color: "#05b4ff"
        Button:
            text: "Back"
            on_release: 
                app.root.current = "main"
                root.manager.transition.direction = "right" 
            
<InfoWindow>:
    name:"info"
    BoxLayout:
        padding: 50
        spacing: 10
        orientation: "vertical"
        Label:
            text: "1. Press Localise"
        Label:
            text: "2. Choose Destination"
        Label:
            text: "3. Scan nearest Aruco Marker when prompted"
        Label:
            text: "4. Follow the path to destination"
        Button:
            text: "Back"
            on_release:
                app.root.current = "main"
                root.manager.transition.direction = "right"

            
""")

class MyApp(App):
    def build(self):
        conn = sqlite3.connect("database.db")
        c = conn.cursor()
        c.execute("""CREATE TABLE if not exists locations(
            place text,
            xcoor int,
            ycoor int)
        """)
        conn.commit()
        conn.close()
        return kv

    def submit(self):
        conn = sqlite3.connect("database.db")
        c = conn.cursor()

        c.execute("SELECT * FROM locations")

        print(c.fetchall())

        conn.commit()
        conn.close()
        

if __name__ == "__main__":
    MyApp().run()

Aruco.py

import numpy as np
import time
import cv2

def detect():
    ARUCO_DICT = {
        "DICT_4X4_50": cv2.aruco.DICT_4X4_50,
        "DICT_4X4_100": cv2.aruco.DICT_4X4_100,
        "DICT_4X4_250": cv2.aruco.DICT_4X4_250,
        "DICT_4X4_1000": cv2.aruco.DICT_4X4_1000,
        "DICT_5X5_50": cv2.aruco.DICT_5X5_50,
        "DICT_5X5_100": cv2.aruco.DICT_5X5_100,
        "DICT_5X5_250": cv2.aruco.DICT_5X5_250,
        "DICT_5X5_1000": cv2.aruco.DICT_5X5_1000,
        "DICT_6X6_50": cv2.aruco.DICT_6X6_50,
        "DICT_6X6_100": cv2.aruco.DICT_6X6_100,
        "DICT_6X6_250": cv2.aruco.DICT_6X6_250,
        "DICT_6X6_1000": cv2.aruco.DICT_6X6_1000,
        "DICT_7X7_50": cv2.aruco.DICT_7X7_50,
        "DICT_7X7_100": cv2.aruco.DICT_7X7_100,
        "DICT_7X7_250": cv2.aruco.DICT_7X7_250,
        "DICT_7X7_1000": cv2.aruco.DICT_7X7_1000,
        "DICT_ARUCO_ORIGINAL": cv2.aruco.DICT_ARUCO_ORIGINAL,
        "DICT_APRILTAG_16h5": cv2.aruco.DICT_APRILTAG_16h5,
        "DICT_APRILTAG_25h9": cv2.aruco.DICT_APRILTAG_25h9,
        "DICT_APRILTAG_36h10": cv2.aruco.DICT_APRILTAG_36h10,
        "DICT_APRILTAG_36h11": cv2.aruco.DICT_APRILTAG_36h11
    }


    def aruco_display(corners, ids, rejected, image):
        if len(corners) > 0:

            ids = ids.flatten()

            for (markerCorner, markerID) in zip(corners, ids):
            
                corners = markerCorner.reshape((4, 2))
                (topLeft, topRight, bottomRight, bottomLeft) = corners
            
                topRight = (int(topRight[0]), int(topRight[1]))
                bottomRight = (int(bottomRight[0]), int(bottomRight[1]))
                bottomLeft = (int(bottomLeft[0]), int(bottomLeft[1]))
                topLeft = (int(topLeft[0]), int(topLeft[1]))

                cv2.line(image, topLeft, topRight, (0, 255, 0), 2)
                cv2.line(image, topRight, bottomRight, (0, 255, 0), 2)
                cv2.line(image, bottomRight, bottomLeft, (0, 255, 0), 2)
                cv2.line(image, bottomLeft, topLeft, (0, 255, 0), 2)
            
                cX = int((topLeft[0] + bottomRight[0]) / 2.0)
                cY = int((topLeft[1] + bottomRight[1]) / 2.0)
                cv2.circle(image, (cX, cY), 4, (0, 0, 255), -1)
            
                cv2.putText(image, str(markerID),(topLeft[0], topLeft[1] - 10), cv2.FONT_HERSHEY_SIMPLEX,
                    0.5, (0, 255, 0), 2)
                print("ArUco marker ID: {}".format(markerID))
                return markerID
        return image




    aruco_type = "DICT_5X5_100"

    arucoDict = cv2.aruco.Dictionary_get(ARUCO_DICT[aruco_type])

    arucoParams = cv2.aruco.DetectorParameters_create()


    capture = cv2.VideoCapture(0)

    capture.set(cv2.CAP_PROP_FRAME_WIDTH, 1280)
    capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 720)


    while capture.isOpened():
    
        ret, img = capture.read()

        h, w, _ = img.shape

        width = 1000
        height = int(width*(h/w))
        img = cv2.resize(img, (width, height), interpolation=cv2.INTER_CUBIC)
 
        corners, ids, rejected = cv2.aruco.detectMarkers(img, arucoDict, parameters=arucoParams)

        detected_markers = aruco_display(corners, ids, rejected, img)

        cv2.imshow("Image", detected_markers)

        key = cv2.waitKey(1) & 0xFF
        if key == ord(" "):
            break

    cv2.destroyAllWindows()
    capture.release()
    return markerID

Answer 1

You can add import Python module on top of kv file content. In your case replace:

kv = Builder.load_string("""
WindowManager:

with:

kv = Builder.load_string("""
#:import Aruco Aruco
WindowManager:

Documentation: https://kivy.org/doc/stable/guide/lang.html#special-syntax