I want my app to switch screen when I click on tile using a function in Kivymd but when I do so i get the following error

Question

from kivymd.app import MDApp
from kivy.lang.builder import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.core.window import Window
from kivy.factory import Factory
from kivy.uix.label import Label
import json
import requests
from functools import partial
happy_food = ['shahi paneer',
              'matar paneer',
              'dum aloo',
              'samosa',
              'tikki',
              'cheese burger',
              'bhindi do pyaza',
              'vegetble chow mein',
              'vegetable sizzler']
d_image = []
d_name = []
d_recipe = []
d_ingridents = []
d_healthlabels = []
for item in happy_food:
    try:
        v = requests.get(
            f"https://api.edamam.com/api/recipes/v2?type=public&q={item}&app_id=68068831&app_key=myapikey`


`&imageSize=LARGE").text
        food_data = json.loads(v)
    except Exception as e:
        pass
    try:
        dish_image = food_data['hits'][0]['recipe']['image']
        d_image.append(dish_image)
    except Exception as e:
        pass
    try:
        dish_name = food_data['hits'][0]['recipe']['label']
        d_name.append(dish_name)
    except Exception as e:
        pass
    try:
        dish_recipe = food_data['hits'][0]['recipe']['shareAs']
        d_recipe.append(dish_recipe)
    except Exception as e:
        pass
    try:
        dish_ingridents = food_data['hits'][0]['recipe']['ingredientLines']
        d_ingridents.append(dish_ingridents)
    except Exception as e:
        pass
    try:
        dish_healthlabels = food_data['hits'][0]['recipe']['healthLabels']
        d_healthlabels.append(dish_healthlabels)
    except Exception as e:
        pass

print(d_name)

Window.size = (320, 600)
style_string = """
<MagicButton@MagicBehavior+MDRaisedButton>
    size_hint: None, None
    size: "200dp", "200dp"
ScreenManager:
    id:screen_manager
    MainScreen:
    Screen1:
    Moodselection:
    Infoscreen:

<MainScreen>:
    name: 'main'
    Image:
        source: "Login1.png"
        allow_stretch:True
    MDLabel:
        text: "Welcome"
        halign: 'center'
        theme_text_color : 'Custom'
        text_color : (255/255.0, 255/255.0, 255/255.0, 1)
        font_size: '40sp'
        font_name: 'Atkinson-Hyperlegible-Regular-102.otf'
        pos_hint :{'center_C': 0.5 ,'center_y':0.9}
    MDLabel:
        text: "Let us suggest what to have!"
        halign: 'center'
        theme_text_color : 'Custom'
        text_color : (255/255.0, 255/255.0, 255/255.0, 1)
        font_size: '20sp'
        font_name: 'Atkinson-Hyperlegible-Regular-102.otf'
        pos_hint :{'center_C': 0.5 ,'center_y':0.85}
    MDTextField:
        id: username
        icon_right:'account'
        hint_text:"Foodie Name"
        size_hint_x : None
        width:225
        pos_hint : {'center_x':0.5,'center_y': 0.52}
        required:True
        helper_text_mode: "on_error"
        helper_text: "Enter text"
        max_text_length: 25
        elevation:8
    MDTextField:
        id: password
        icon_right:'lock'
        hint_text:"Password"
        size_hint_x : None
        width:225
        pos_hint : {'center_x':0.5,'center_y': 0.4}
        required:True
        helper_text_mode: "on_error"
        helper_text: "Enter text"
        max_text_length: 25
        password :True
    MagicButton:
        text: "LOGIN"
        on_press: root.show_data()
        on_release: self.grow()
        pos_hint: {"center_x": .5, "center_y": .3}
        size_hint: None, None
        size: "200dp", "280dp"
        
    MagicButton:
        text: "SignUp"
        pos_hint: {"center_x": .5, "center_y": .2}
        on_release: self.grow()
<MyTile@SmartTileWithLabel>
    size_hint: None,None
    size:100,100
    
    
<Screen1>:
    name :'S1'
    MDBoxLayout:
        padding: "2dp"
        size_hint:None,None
        size:320,580
        pos_hint: {"center_x": .5, "center_y": .51}
        
        ScrollView:
            MDList:
                id:box
                cols: 3
                padding: dp(4), dp(4)
                spacing: dp(4)
                elevation_normal:20
       
    MDBottomAppBar:
        MDToolbar:
            icon: "food"
            type: "bottom"
            left_action_items: [["magnify", lambda x: x],["account", lambda x: root.go_back()]]
            right_action_items:[["coffee", lambda x: x],["plus-circle-outline", lambda x: x]]
        
<Moodselection>:
    name:'moodselect'
    MDCard:
        size_hint: None, None
        size: "280dp", "180dp"
        pos_hint: {"center_x": .4, "center_y": .79}
        radius:[20,]
        
        MDLabel:
            text: "How are you feeling?"
            halign: 'center'
            font_size: '40sp'
            font_name: 'Atkinson-Hyperlegible-Regular-102.otf'
            theme_text_color : 'Custom'
            text_color : (26/255.0, 83/255.0, 255/255.0, 1)
            
    MDChip:
        text: 'Happy'
        color: (255/255.0, 255/255.0, 77/255.0, 1)
        icon: 'emoticon-happy'
        pos_hint: {"center_x": .5, "center_y": .45}
        check:True
        icon_color:(255/255.0, 77/255.0, 77/255.0, 1)
    MDChip:
        text: 'Sad'
        color: (255/255.0, 51/255.0, 119/255.0, 1)
        icon: 'emoticon-sad'
        pos_hint: {"center_x": .5, "center_y": .4}
        check:True
        icon_color:(102/255.0, 51/255.0, 255/255.0, 1)
    MDChip:
        text: 'Loved'
        color: (179/255.0, 0/255.0, 0/255.0, 1)
        icon: 'heart'
        pos_hint: {"center_x": .5, "center_y": .35}
        check:True
        icon_color:(255/255.0, 80/255.0, 80/255.0, 1)
    MDChip:
        text: 'Angry'
        color: (255/255.0, 64/255.0, 0/255.0, 1)
        icon: 'emoticon-angry'
        pos_hint: {"center_x": .5, "center_y": .3}
        check:True
        icon_color:(255/255.0, 102/255.0, 0/255.0, 1)
            
            
    MagicButton:
        text: "LetsGo!"
        align:'center'
        on_press: root.s1_content()
        on_release: self.grow()
        pos_hint: {"center_x": .5, "center_y": .2}
        
        
<Infoscreen>:
    name:'infoscreen'
    MagicButton:
        text: "LetsGo!"
        align:'center'
        on_release: self.grow()
        pos_hint: {"center_x": .5, "center_y": .2}
    
        
    

"""


class MainScreen(Screen):
    def show_data(self):
        username = self.ids.username.text
        password = self.ids.password.text
        if password == "1234":
            print("Login success!")
            self.manager.current = 'moodselect'


class Moodselection(Screen):
    c = 0
    def s1_content(self):
        self.manager.current = 'S1'
        for i in range(len(d_name)):
            tile = Factory.MyTile(source=d_image[i])
            tile.text = d_name[i]
            tile.id = "t" + str(i)
            tile.bind(on_release=Screen1.newdata)
            self.manager.get_screen('S1').ids.box.add_widget(tile)



class Screen1(Screen):
    def newdata(self):
        self.manager.current = 'infoscreen'


    def go_back(self):
        self.manager.current = 'moodselect'


class Infoscreen(Screen):
    pass

global sn
sn = ScreenManager()
sn.add_widget(MainScreen(name='main'))
sn.add_widget(Screen1(name='S1'))
sn.add_widget(Moodselection(name='moodselect'))
sn.add_widget(Infoscreen(name='infoscreen'))


class foodapp(MDApp):
    def build(self):
        screen = Screen()
        self.theme_cls.primary_palette = 'Teal'
        self.theme_cls.primary_hue = "100"
        style = Builder.load_string(style_string)
        screen.add_widget(style)
        return screen


foodapp().run()

I get this error when I click on tile, I have tried sn.current='infoscreen' it is not working. I get this error when I click on tile, I have tried sn.current='infoscreen' it is not working. I get this error when I click on tile, I have tried sn.current='infoscreen' it is not working. I get this error when I click on tile, I have tried sn.current='infoscreen' it is not working. I get this error when I click on tile, I have tried sn.current='infoscreen' it is not working. I get this error when I click on tile, I have tried sn.current='infoscreen' it is not working. I get this error when I click on tile, I have tried sn.current='infoscreen' it is not working.

[INFO   ] [Logger      ] Record log in C:\Users\nitis\.kivy\logs\kivy_21-06-19_31.txt
[INFO   ] [deps        ] Successfully imported "kivy_deps.gstreamer" 0.3.2
[INFO   ] [deps        ] Successfully imported "kivy_deps.angle" 0.3.0
[INFO   ] [deps        ] Successfully imported "kivy_deps.glew" 0.3.0
[INFO   ] [deps        ] Successfully imported "kivy_deps.sdl2" 0.3.1
[INFO   ] [Kivy        ] v2.0.0
[INFO   ] [Kivy        ] Installed at "C:\Python38\lib\site-packages\kivy\__init__.py"
[INFO   ] [Python      ] v3.8.5 (tags/v3.8.5:580fbb0, Jul 20 2020, 15:57:54) [MSC v.1924 64 bit (AMD64)]
[INFO   ] [Python      ] Interpreter at "C:\Python38\python.exe"
[INFO   ] [KivyMD      ] 0.104.2.dev0, git-Unknown, 2021-06-03 (installed at "C:\Python38\lib\site-packages\kivymd\__init__.py")
[INFO   ] [Factory     ] 186 symbols loaded
[INFO   ] [Image       ] Providers: img_tex, img_dds, img_sdl2, img_pil (img_ffpyplayer ignored)
[INFO   ] [Text        ] Provider: sdl2
[INFO   ] [Window      ] Provider: sdl2
[INFO   ] [GL          ] Using the "OpenGL" graphics system
[INFO   ] [GL          ] GLEW initialization succeeded
[INFO   ] [GL          ] Backend used <glew>
[INFO   ] [GL          ] OpenGL version <b'4.6.0 - Build 27.20.100.9466'>
[INFO   ] [GL          ] OpenGL vendor <b'Intel'>
[INFO   ] [GL          ] OpenGL renderer <b'Intel(R) UHD Graphics 620'>
[INFO   ] [GL          ] OpenGL parsed version: 4, 6
[INFO   ] [GL          ] Shading version <b'4.60 - Build 27.20.100.9466'>
[INFO   ] [GL          ] Texture max size <16384>
[INFO   ] [GL          ] Texture max units <32>
[INFO   ] [Window      ] auto add sdl2 input provider
[INFO   ] [Window      ] virtual keyboard not allowed, single mode, not docked
[INFO   ] [GL          ] NPOT texture support is available
['Shahi Paneer', 'Matar Paneer', 'Dum Aloo | Baby Potatoes in Yogurt Gravy', 'Samosa', 'Aloo Tikki Sandwich', 'Blue Cheese Burger', 'BHINDI DO PYAZA', 'Vegetable sizzler']
[INFO   ] [Base        ] Start application main loop
Login success!
[INFO   ] [Loader      ] using a thread pool of 2 workers
[INFO   ] [Base        ] Leaving application in progress...
 Traceback (most recent call last):
   File "C:/Users/nitis/Desktop/pythonProject/KivyAppsdev/Foodapp.py", line 276, in <module>
     foodapp().run()
   File "C:\Python38\lib\site-packages\kivy\app.py", line 950, in run
     runTouchApp()
   File "C:\Python38\lib\site-packages\kivy\base.py", line 582, in runTouchApp
     EventLoop.mainloop()
   File "C:\Python38\lib\site-packages\kivy\base.py", line 347, in mainloop
     self.idle()
   File "C:\Python38\lib\site-packages\kivy\base.py", line 391, in idle
     self.dispatch_input()
   File "C:\Python38\lib\site-packages\kivy\base.py", line 342, in dispatch_input
     post_dispatch_input(*pop(0))
   File "C:\Python38\lib\site-packages\kivy\base.py", line 308, in post_dispatch_input
     wid.dispatch('on_touch_up', me)
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Python38\lib\site-packages\kivymd\uix\behaviors\ripple_behavior.py", line 296, in on_touch_up
     return super().on_touch_up(touch)
   File "C:\Python38\lib\site-packages\kivy\uix\behaviors\button.py", line 179, in on_touch_up
     self.dispatch('on_release')
   File "kivy\_event.pyx", line 705, in kivy._event.EventDispatcher.dispatch
   File "kivy\_event.pyx", line 1248, in kivy._event.EventObservers.dispatch
   File "kivy\_event.pyx", line 1172, in kivy._event.EventObservers._dispatch
   File "C:/Users/nitis/Desktop/pythonProject/KivyAppsdev/Foodapp.py", line 248, in newdata
     self.manager.current = 'infoscreen'
 **AttributeError: 'MyTile' object has no attribute 'manager'**

score 0 · Accepted Answer · answered Jun 19 '21 at 18:18

Trying to change Screens using sn.current will not work, because sn is not actually part of your App.

The lines of code:

sn = ScreenManager()
sn.add_widget(MainScreen(name='main'))
sn.add_widget(Screen1(name='S1'))
sn.add_widget(Moodselection(name='moodselect'))
sn.add_widget(Infoscreen(name='infoscreen'))

are building a widget tree, but that tree (rooted at sn) is never useed in your App. Those lines can be deleted.

When you use:

tile.bind(on_release=Screen1.newdata)

You are confusing static methods with instance methods. The newdata method of Screen1 is an instance method and is expecting to receive a self argument (provided automatically when correctly called as an instance method). By binding the MyTile to that method as Screen1.newdata, it provides a reference to the MyTile instance as the argument, and the newdata method mistakes the MyTile instance as the expected self argument. That produces the described error.

I believe you can fix that by creating a newdata method in the Moodselection class and binding to that method:

class Moodselection(Screen):
    c = 0
    def s1_content(self):
        self.manager.current = 'S1'
        for i in range(len(d_name)):
            tile = Factory.MyTile(source=d_image[i])
            tile.text = d_name[i]
            tile.id = "t" + str(i)
            tile.bind(on_release=self.newdata)
            self.manager.get_screen('S1').ids.box.add_widget(tile)
    def newdata(self, *args):
        self.manager.current = 'infoscreen'

Not part of this issue, but unless thee is a specific reason for the construction you have used, you can simplify your build() method:

class foodapp(MDApp):
    def build(self):
        self.theme_cls.primary_palette = 'Teal'
        self.theme_cls.primary_hue = "100"
        style = Builder.load_string(style_string)
        return style

Thanks a lot, it actually solved my problem! and thank you for the extra build method tip :) — Nitish, Jun 20 '21 at 08:54

I want my app to switch screen when I click on tile using a function in Kivymd but when I do so i get the following error

1 Answers1