custom_button.py

__all__ = ('AnimatedButton')

from kivy.factory import Factory
from kivy.uix.label import Label
from kivy.uix.image import Image
from kivy.graphics import *
from kivy.properties import StringProperty, OptionProperty,\
                             ObjectProperty, BooleanProperty



class AnimatedButton(Label):

    state = OptionProperty('normal', options=('normal', 'down'))

    allow_stretch = BooleanProperty(True)

    keep_ratio = BooleanProperty(False)

    border = ObjectProperty(None)

    anim_delay = ObjectProperty(None)

    background_normal = StringProperty('data/images/button.png')

    texture_background = ObjectProperty(None)

    background_down = StringProperty('data/images/button_pressed.png')

    def __init__(self, **kwargs):
        super(AnimatedButton, self).__init__(**kwargs)

        self.register_event_type('on_press')
        self.register_event_type('on_release')
        #borderImage.border by default is ...
        self.border = (16, 16, 16, 16)
        #Image to display depending on state
        self.img = Image(source = self.background_normal,
                        allow_stretch = self.allow_stretch,
                        keep_ratio = self.keep_ratio, mipmap = True)
        #reset animation if anim_delay is changed
        def anim_reset(*l):
            self.img.anim_delay = self.anim_delay
        self.bind(anim_delay = anim_reset)
        self.anim_delay = .1
        #update self.texture when image.texture changes
        self.img.bind(texture = self.on_tex_changed)
        self.on_tex_changed()
        #update image source when background image is changed
        def background_changed(*l):
            self.img.source = self.background_normal
            self.anim_delay = .1 
        self.bind(background_normal = background_changed)

    def on_tex_changed(self, *largs):
        self.texture_background = self.img.texture

    def _do_press(self):
        self.state = 'down'

    def _do_release(self):
        self.state = 'normal'

    def on_touch_down(self, touch):
        if not self.collide_point(touch.x, touch.y):
            return False
        if self in touch.ud:
            return False
        touch.grab(self)
        touch.ud[self] = True
        _animdelay = self.img.anim_delay
        self.img.source = self.background_down
        self.img.anim_delay = _animdelay
        self._do_press()
        self.dispatch('on_press')
        return True

    def on_touch_move(self, touch):
        return self in touch.ud

    def on_touch_up(self, touch):
        if touch.grab_current is not self:
            return
        assert(self in touch.ud)
        touch.ungrab(self)
        _animdelay = self.img._coreimage.anim_delay
        self.img.source = self.background_normal
        self.anim_delay = _animdelay
        self._do_release()
        self.dispatch('on_release')
        return True

    def on_press(self):
        pass

    def on_release(self):
        pass

Factory.register('AnimatedButton', cls=AnimatedButton)