propblem.py

from kivy.config import Config
Config.set('kivy', 'log_level', 'debug')

from kivy.app import App
from kivy.lang import Builder
from kivy.factory import Factory
from kivy.uix.boxlayout import BoxLayout
from kivy.logger import Logger
from kivy.clock import Clock

kv = """
#:import h2c kivy.parser.parse_color

<Test>:
    id: 'color_change_screen'
    BoxLayout:
        orientation: 'vertical'
        padding: 10
        Label:
            text: 'Paint Colors to Change'
            color: h2c('#3498DB')
            font_size: 36
            markup: True
        BoxLayout:
            Label:
                id: lbl_time_allowed_per_color
                text: 'Time allowed per color: [color=#E67E22]10[/color] Minutes'
                font_size: 32
                markup: True
        BoxLayout:
            Label:
                text: 'Colors to change:'
                font_size: 32
                size_hint_x: .5
            Slider:
                id: sld_colors_to_change
                left: 0
                size_hint_x: .25
                min: 1
                max: 15
                value: 1
                step: 1
            Label:
                text: str(root.ids['sld_colors_to_change'].value)
                color: h2c('#E67E22')
                font_size: 32
                markup: True
                size_hint_x: .25
                # value: str(int(root.ids['sld_colors_to_change'].value) if root.ids['sld_colors_to_change'].value else '0')
        BoxLayout:
            Label:
                text: 'Time allowed:'
                font_size: 32
            Label:
                id: lbl_time_allowed
                text: '10'
                color: h2c('#E67E22')
                font_size: 32
                # font_name: 'LCDMono'
                markup: True
                # value: '{0:02d}:{1:02d}:00'.format(*divmod( int(root.ids['sld_colors_to_change'].value) * root.ids['time_allowed_per_color'], 60 ) )  # this works
        BoxLayout:
            Label:
                text: 'Elapsed:'
                font_size: 32
            Label:
                id: lbl_elapsed_time
                color: h2c('#E67E22')
                text: '00:00:00'
                font_size: 36
                # font_name: 'LCDMono'
                markup: True
        BoxLayout:
            spacing: 10
            Button:
                id: btn_start
                text: 'Start'
                font_size:36
                background_normal: ''
                background_color: h2c('#2ECC71')
                padding: [250, 50]
                on_release: root.btn_start_timer()
            Button:
                id: btn_stop
                text: 'Cancel'
                font_size: 36
                background_normal: ''
                background_color: h2c('#C0392B')
                padding: [250, 50]
                on_release: root.btn_stop_cancel_timer()
"""

Builder.load_string(kv)


class Test(BoxLayout):
    # timer variables
    sw_started = False
    sw_seconds = 0
    # time_allowed_per_color = NumericProperty()
    # sld_colors_to_change = NumericProperty()

    def __init__(self, *args, **kwargs):
        super(Test, self).__init__(*args, **kwargs)
        self.callback()

    def callback(self):
        pass

    def btn_start_timer(self):
        if not self.sw_started:
            Logger.info('ThreadChangeScreen: Starting the Thread Change timer')
            # start the timer
            self.sw_started = True
            self.sw_seconds = 0
            Clock.schedule_interval(self.ticktock, 0)  # update the clock every clock cycle
            # post data. Here we send the # of colors in elapsed_time.
#            self.app.do_post(event_type=15, reason_code=str(self.ids['sld_colors_to_change'].value))
            # update the Start button
            self.ids.btn_stop.text = 'Stop'
            self.ids.btn_start.disabled = True

    def btn_stop_cancel_timer(self):
        if self.sw_started:
            Logger.info('ThreadChangeScreen: Stopping the Color Change timer')
            # turn off the timer
            Clock.unschedule(self.ticktock)
            self.sw_started = False
            self.ids.btn_start.disabled = False
            # post data. Here we send the elapsed time for the change.
#            self.app.do_post(event_type=16, elapsed_time=int(self.sw_seconds))
            # reset the stop button and timer
            self.ids.lbl_elapsed_time.text = '00:00:00'
            self.parent.current = 'operator_panel_screen'
        else:
            # Return to Operator Panel Screen without doing anything
            Logger.info('ThreadChangeScreen: Operator canceled the Color Change operation')
            self.parent.current = 'operator_panel_screen'

    def ticktock(self, nap):
        # set the timer value
        self.sw_seconds += nap
        # convert the seconds to h, m s for displaying
        m, s = divmod(self.sw_seconds, 60)
        h, m = divmod(m, 60)
        txt = '%d:%02d:%02d[/size].%02d' % (int(h), int(m), int(s), int(s * 100 % 100))
        self.ids.lbl_elapsed_time.text = txt
        # self.ids.lbl_elapsed_time.text = ('%d:%02d:%02d[/size].%02d' % (int(h), int(m), int(s), int(s * 100 % 100)))


class TestApp(App):
    def build(self):
        return Test()

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