flexible number of objects in kivy scrollview

Question

I am trying to use input on one screen to make a list on a second screen using kivy. The basic idea is that a paragraph is broken up into words, which are then displayed on another page. Below is a minimum example.

What is happening is that the words are getting squished together, and there's no scrolling.

In main.py:

from kivy.app import App
from kivy.app import Widget

from kivy.uix.floatlayout import FloatLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.properties import ObjectProperty


class InputScreen(Screen):
    wordList = ObjectProperty()
    def getwords(self):
        self.wordList=[]
        s = self.ids.textInput.text.split()
        for w in s:
            for punctuation in [',','.','!','?']:
                w.strip(punctuation)

            self.wordList.append(w)

        return None

class WordLabel(Label):
    pass

class WordScreen(Screen):
    wordList = ObjectProperty()
    def updateWords(self):
        self.ids.scrollContainer.clear_widgets()
        wordGrid = GridLayout(cols=2,size_hint_y=None)
        wordGrid.bind(minimum_height=wordGrid.setter('height'))
        for w in self.wordList:
            wordGrid.add_widget(Label(text=w))
            wordGrid.add_widget(Label(text='property of word'))

        self.ids.scrollContainer.add_widget(wordGrid)

class testScreenManager(ScreenManager):
    pass

class testApp(App):
    def build(self):
        sm = testScreenManager()
        return sm


if __name__=='__main__':
    testApp().run()

In test.kv:

<testScreenManager>
    InputScreen:
        id: inputScreen
        name: 'input'
    WordScreen:
        id: wordScreen
        name: 'word'
        wordList: inputScreen.wordList


<InputScreen>:
    GridLayout:
        cols: 1
        TextInput:
            id: textInput
            hint_text: 'Input paragraph'
        BoxLayout:
            orientation: 'horizontal'
            size_hint_y: .2
            Button:
                text: 'Analyze paragraph'
                on_press: root.getwords()
            Button:
                text: 'See word list'
                on_press:
                    root.getwords()
                    root.manager.transition.direction = 'left'
                    root.manager.current = 'word'
        BoxLayout:
            orientation: 'horizontal'
            size_hint_y: .2
            Label:
                id: wordCountResult
                text: ''


<WordScreen>:
    on_enter: root.updateWords()
    BoxLayout:
        orientation: 'vertical'
        BoxLayout:
            id: rowLabels
            orientation: 'horizontal'
            size_hint_y: .2
            Label:
                text: 'Words not at grade level:'
                size_hint_x: .5
            Label:
                text: 'Grade Level'
                size_hint_x: .5
        ScrollView:
            id: scrollContainer
            size_hint: (None,None)
            size: (self.parent.width,self.parent.height - rowLabels.height - buttonRow.height)
        Button:
            id: buttonRow
            size_hint_y: .2
            text: 'Back'
            on_press:
                root.manager.transition.direction = 'right'
                root.manager.current = 'input'
<WordLabel>:
    size_hint_y: None
    height: '29sp'

I've tried using size_hint_y=.6 for the ScrollView, and swapping height and minimum_height in the wordGrid.bind(minimum_height=wordGrid.setter('height')).

What I thought was going to happen, is that the ScrollView container will be the height of the window minus the height used by two other widgets. Inside the ScrollView, WordGrid is longer (the height is bound to the minimum height necessary for all children) and so the scrolling is used to see all the items. I must not be understanding some fact about heights/sizes of ScrollView, WordGrid, and WordGrid's children. Anyone have some insight?

score 0 · Accepted Answer · edited May 23 '17 at 11:58

In this part of the code:

for w in self.wordList:
        wordGrid.add_widget(Label(text=w))
        wordGrid.add_widget(Label(text='property of word'))

the Label by default will have size_hint_y=1. Instead, size_hint_y=None is necessary. A height can be set, as is done in the WordLabel class - which was what the OP (by me) meant to do.

Thanks to related question Kivy ScrollView - Not Scrolling for helping me to realize the error.

flexible number of objects in kivy scrollview

1 Answers1