Untitled

from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.textinput import TextInput
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.scrollview import ScrollView
class ScrButton(Button):
  def __init__(self, screen, direction='right', goal='main', **kwargs):
      super().__init__(**kwargs)
      self.screen = screen
      self.direction = direction
      self.goal = goal
  def on_press(self):
      self.screen.manager.transition.direction = self.direction
      self.screen.manager.current = self.goal
    
class MainScr(Screen):
  def __init__(self, **kwargs):
      super().__init__(**kwargs)
      vl = BoxLayout(orientation='vertical', padding=8, spacing=8)
      hl = BoxLayout()
      txt = Label(text= 'Выбери экран')
      vl.add_widget(ScrButton(self, direction='down', goal='first', text="1"))
      vl.add_widget(ScrButton(self, direction='left', goal='second', text="2"))
      vl.add_widget(ScrButton(self, direction='up', goal='third', text="3"))
      vl.add_widget(ScrButton(self, direction='right', goal='fourth', text="4"))
      hl.add_widget(txt)
      hl.add_widget(vl)
      self.add_widget(hl)
class FirstScr(Screen):
  def __init__(self, **kwargs):
      super().__init__(**kwargs)
      vl = BoxLayout(orientation='vertical', size_hint=(.5, .5), pos_hint={'center_x': 0.5, 'center_y': 0.5})
      btn = Button(text= 'Выбор: 1', size_hint=(.5, 1), pos_hint={'left': 0})
      btn_back = ScrButton(self, direction='up', goal='main', text="Назад", size_hint=(.5, 1), pos_hint={'right': 1})
      vl.add_widget(btn)
      vl.add_widget(btn_back)
      self.add_widget(vl)
class SecondScr(Screen):
  def __init__(self, **kwargs):
      super().__init__(**kwargs)
      vl = BoxLayout(orientation='vertical')
      self.txt = Label(text= 'Выбор: 2')
      vl.add_widget(self.txt)


      hl_0 = BoxLayout(size_hint=(0.8, None), height='30sp')
      lbl1 = Label(text='Введите пароль:', halign='right')
      self.input = TextInput(multiline=False)


      hl_0.add_widget(lbl1)
      hl_0.add_widget(self.input)
      vl.add_widget(hl_0)
     
      hl = BoxLayout(size_hint=(0.5, 0.2), pos_hint={'center_x': 0.5})
      btn_false = Button(text="OK!")
      btn_back = ScrButton(self, direction='right', goal='main', text="Назад")


      hl.add_widget(btn_false)
      hl.add_widget(btn_back)
      vl.add_widget(hl)
      self.add_widget(vl)
      btn_false.on_press = self.change_text
  def change_text(self):
      self.txt.text = self.input.text + '? Не сработало ...'      
class ThirdScr(Screen):
  def __init__(self, **kwargs):
      super().__init__(**kwargs)
      layout = BoxLayout(orientation='vertical')
      btn_back = ScrButton(self, direction='down', goal='main', text="Назад", size_hint=(1, None), height='40sp')
      test_label = Label(text = "Твой собственный экран")
      layout.add_widget(test_label)
      layout.add_widget(btn_back)
      self.add_widget(layout)


class FourthScr(Screen):
  def __init__(self, **kwargs):
      super().__init__(**kwargs)
      vl = BoxLayout(orientation='vertical', spacing=8)
      a = 'START ' + 'Выбор: 3 ' * 200
      test_label = Label(text = "Дополнительное задание",size_hint=(0.3,None))


      btn_back = ScrButton(self, direction='left', goal='main', text="Назад", size_hint=(1, .2), pos_hint={'center-x': 0.5})
      self.label = Label(text=a, size_hint_y=None, font_size='24sp', halign='left', valign='top') 
      self.label.bind(size=self.resize)
      self.scroll = ScrollView(size_hint=(1, 1))
      self.scroll.add_widget(self.label)


      vl.add_widget(test_label)
      vl.add_widget(btn_back)
      vl.add_widget(self.scroll)
      self.add_widget(vl)
  def resize(self, *args):
      self.label.text_size = (self.label.width, None)
      self.label.texture_update()
      self.label.height = self.label.texture_size[1]


class MyApp(App):
  def build(self):
      sm = ScreenManager()
      sm.add_widget(MainScr(name='main'))
      sm.add_widget(FirstScr(name='first'))
      sm.add_widget(SecondScr(name='second'))
      sm.add_widget(ThirdScr(name='third'))
      sm.add_widget(FourthScr(name='fourth'))
      return sm
MyApp().run()