Incorrect determinate MDSpinner behaviour?

[mhuangwm]

Description of the Bug

The determinate MDSpinner with an indeterminate manner first load.
The MDSpinner with determinate does not rotate with a static starting point on second load.
(See gif)

Not sure if this is the intended behaviour, but I was expecting a behaviour to something like this:
https://kstatic.googleusercontent.com/files/22d91d17b8958635c1cc769856551760bf3f7c8ea274e01e017d2ca7b5b3833a3cea4a4155bdf32c3d365dc9d3b5d0757d87be8f6c97854f16b4b419df6fa030

Code and Logs

from kivy.lang import Builder
from kivymd.app import MDApp
KV = '''
Screen:
    MDSpinner:
        size_hint: None, None
        size: dp(100), dp(100)
        pos_hint: {'center_x': .5, 'center_y': .5}
        active: True if check.active else False
        determinate: True
        determinate_time: 20
    MDCheckbox:
        id: check
        size_hint: None, None
        size: dp(48), dp(48)
        pos_hint: {'center_x': .5, 'center_y': .4}
        active: True
'''
class Test(MDApp):
    def build(self):
        return Builder.load_string(KV)
Test().run()

Screenshots

Versions

• OS:Ubuntu 20.04
• Python: 3.7.9
• Kivy: 2.00
• KivyMD: 0.104.2.dev0

[mhuangwm]

I think the problem comes from the init where to animation starts without waiting for the kv rules to apply:

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.color = self.theme_cls.primary_color

        ....

        if self.determinate:
            self._start_determinate()
        else:
            self._start_loop()

we should probably remove that and wait for kv rules to be applied before start:

    def on_kv_post(self, base_widget):
        if not self.active:
            return

        if self.determinate:
            self._start_determinate()
        else:
            self._start_loop()

result: