kv file

#: import FadeTransition kivy.uix.screenmanager.FadeTransition

#:kivy 1.9.1
# main.py

ScreenManagement:
	transition: FadeTransition()

	MainScreen:
	CategorySelectScreen:
	DictScreen:

## GŁÓWNY EKRAN
<MainScreen>:
	name: "main"
    canvas:
		## RYSOWANIE BIAŁEGO TŁA ##
        Color:
            rgb: (1, 1, 1)
        Rectangle:
            pos: self.pos
            size: self.size

	## PRZYCISK START
	Button:
		background_color: (1.0, 0.0, 0.0, 1.0)
		text: "Start"
		on_release: app.root.current = "categoryscreen"
		size_hint: .2, .1
		pos_hint: {"center_x":.5, 'center_y':.5}

## EKRAN WYBORU KATEGORII
<CategorySelectScreen>:
	name: "categoryscreen"

	canvas:
		## RYSOWANIE BIAŁEGO TŁA ##
        Color:
            rgb: (1, 1, 1)
        Rectangle:
            pos: self.pos
            size: self.size

	BoxLayout:
		orientation:"vertical"
		Label:
			id: category_screen_title_label
			text:"Wybierz kategorię"
			color: 0,0,0,1
			size_hint: 1, 0.1
			font_size: sp(25)

		## SPORT ##
		Button:
			background_color: (1.0, 0.0, 0.0, 1.0)
			text: "Sport"
			on_release:
				root.selected = "Sport"
				app.root.current = "dict"
			size_hint: None,None
			pos_hint: {"center_x":.5, 'center_y':.5}

		## FOOD ##
		Button:
			background_color: (1.0, 0.0, 0.0, 1.0)
			text: "Food"
			on_release:
				root.selected = "Food"
				app.root.current = "dict"
			size_hint: None,None
			pos_hint: {"center_x":.5, 'center_y':.5}

## EKRAN SŁOWNIKA
<DictScreen>:
	name: "dict"
	canvas:
		## RYSOWANIE BIAŁEGO TŁA ##
		Color:
            rgb: (1, 1, 1)
        Rectangle:
            pos: self.pos
            size: self.size

	## wybrana kategoria
	current_category:root.manager.get_screen('categoryscreen').selected
	selected_objects:root.CategorySelect(root.objects,root.current_category)

	BoxLayout: 						## główny kontener
		orientation:'vertical'

		## KATEGORIA
		Label:
			id: categoryname_label
			text:root.ChangeCategory(root.selected_objects,root.index)
			color: 0,0,0,1
			size_hint: 1, 0.2
			font_size: sp(50)

		## OBRAZEK
		Image:
			id: item_image
			source: root.ChangeImage(root.selected_objects,root.index)
			keep_ratio: True
			allow_stretch: True
			pos_hint: {"center_x":.5}
			size_hint: 0.9, 0.8

		## NAZWA
		Label:
			id: name_label
			text:root.ChangeLabel(root.selected_objects,root.index)
			color: 0,0,0,1
			size_hint: 1, 0.1
			font_size: sp(25)

		## LICZNIK
		Label:
			id: counter_label
			text:"("+str(root.index+1)+"/"+str(len(root.selected_objects))+")"
			color: 0,0,0,1
			size_hint: 1, 0.1
			font_size: sp(15)

		## DOLNY PANEL Z PRZYCISKAMI
		BoxLayout:
			size_hint: 1,0.2
			orientation:'horizontal'
			FloatLayout:
				pos_hint:{"right":1}
				## COFNIJ DO MENU
				Button:
					id: back_button
					background_normal:'data/img/leftarrow.png'
					background_down:'data/img/leftarrow.png'
					background_color:1,0,0,1
					border: 1,1,1,1
					on_release: app.root.current = "main"
					size_hint: 0.1,.5

				BoxLayout:
					pos_hint:{"right":1}
					size_hint:0.2,.5
					orientation:'horizontal'
					## POPRZEDNI ELEMENT
					Button:
						id: prev_button
						on_release:
							root.index=root.PrevItem(root.selected_objects,root.index)
							item_image.source=root.ChangeImage(root.selected_objects,root.index)
							name_label.text=root.ChangeLabel(root.selected_objects,root.index)
							categoryname_label.text=root.ChangeCategory(root.selected_objects,root.index)
							counter_label.text="("+str(root.index+1)+"/"+str(len(root.selected_objects))+")"
						background_normal:'data/img/leftarrow.png'
						background_down:'data/img/leftarrow.png'
						border: 1,1,1,1

					## NASTĘPNY ELEMENT
					Button:
						id: next_button
						on_release:
							root.index=root.NextItem(root.selected_objects,root.index)
							item_image.source=root.ChangeImage(root.selected_objects,root.index)
							name_label.text=root.ChangeLabel(root.selected_objects,root.index)
							categoryname_label.text=root.ChangeCategory(root.selected_objects,root.index)
							counter_label.text="("+str(root.index+1)+"/"+str(len(root.selected_objects))+")"
						background_normal:'data/img/rightarrow.png'
						background_down:'data/img/rightarrow.png'
						border: 1,1,1,1