Triggering screenmanager to change screen in Kivy from an if conditional

Question

I'm creating a day and time-selection option for the user. For that, I'm trying to create a button that only moves to the next screen (when clicked) when all the spinners have values selected.

For the program to identify when the spinners have been clicked (The day, hour and minute spinners), I have assigned a True value for state in the .kv code for each of the spinners. The screenmanager will shift from screen_two to screen_three only if all of the spinners have a state: True. I assign True when the spinner is clicked on (and an option is selected).

Most of the code works as expected, except for the if statement in the kv code I have shown below.

I have removed most of my code and kept only the relevant snippets.

The .kv file

<ScreenTwo>:
    FloatLayout:
        Button:
            background_color: 0, 0, 0, 1
            size: (400, 130)
            size_hint: (None, None)
            pos_hint: {'right': 0.6, 'center_y': 0}
            on_press:
                root.hours_checking() #this function converts the 12hr time to 24hr time

The states of each of the spinners is checked (individual spinner states are identified by the IDs I've assigned).

                if day.state == hours.state == minutes.state == AmPm.state == 'True': \
                root.manager.current = 'screen_three'

        Spinner:
            id: day
            size_hint: None, None
            size: 100, 44
            pos_hint: {'center': (.5, .5)}
            text: 'Day'
            values: 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'
            on_text:
                root.on_day_select(self.text) #this function sends back the selected day value in the spinner
                self.state: 'True'
        Spinner:
            id: hours
            size_hint: None, None
            size: 100, 44
            pos_hint: {'center': (.1, .5)}
            text: 'Hour'
            values: '01', '02', '03', '04', '05', '06', '07', '08', '09', '10', '11', '12'
            on_text:
                root.on_hours_select(self.text) #this function sends back the selected hours value in the spinner
                self.state: 'True'
        Spinner:
            id: minutes
            size_hint: None, None
            size: 100, 44
            pos_hint: {'center': (.3, .5)}
            text: 'Minutes'
            values: '00', '15', '30', '45'
            on_text:
                root.on_minutes_select(self.text) #this function sends back the selected minutes value in the spinner
                self.state: 'True'
        Spinner:
            id: AmPm
            size_hint: None, None
            size: 100, 44
            pos_hint: {'center': (.4, .5)}
            text: 'AM/PM'
            values: 'a.m', 'p.m'
            on_text:
                root.on_AmPm_select(self.text) #this function sends back the selected day a.m/p.m value in the spinner
                self.state: 'True'

The python file

class ScreenTwo(Screen):
    def on_day_select(self, text): #Function assigns selected day from spinner to a variable
        global day
        day = str(text)
    def on_hours_select(self, text): #Function assigns selected 12-hour from spinner to a variable
        global hours
        hours = int(text)
    def on_minutes_select(self, text): #Function assigns selected minute from spinner to a variable
        global minutes
        minutes = int(text)
    def on_AmPm_select(self,text): #Function assigns selected a.m/p.m from spinner to a variable
        global AmPm
        AmPm = str(text)
    def hours_checking(self): #Function converts 12hr time to 24hr time
        global AmPm
        global hours
        global minutes
        global day
        try:
            if 1 <= hours <= 11 and AmPm == 'a.m':
                pass
            elif 1 <= hours <= 12 and AmPm == 'p.m':
                hours += 12
            elif hours == 12 and AmPm == 'a.m':
                hours = 0
        except:
            print('error')
        else:
            print(day, hours, minutes)
    pass

When this code is run and I click the button, I receive the 12hr time in the 24hr time format. Which means everything up till the screenmanager part in the kv file (which is shown in the code block, highlighted in the yellow part) runs perfectly. I'm very new to Kivy and OOP, so please help me see where I exactly went wrong.

Answer 1

You can create your own property for your purpose by creating an extension of the Spinner like this:

class MySpinner(Spinner):
    current_selection = BooleanProperty(False)

Then, replace Spinner in your kv with MySpinner, and everywhere that you reference the state of a MySpinner, replace it with current_selection.