在 Kivy 中同步动画

Question

我正在编写一个简单的视错觉应用程序，以学习如何在 Kivy 中编写代码。我想知道我的程序为什么会崩溃以及如何解决。如果我取消注释 animation.start(self.c4) 行，那么我的程序运行良好，所以我几乎可以肯定问题是两个动画同时是运行。错误是什么以及如何解决？

我的 .py 文件：

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.properties import NumericProperty, ObjectProperty,\
ReferenceListProperty
from kivy.graphics import Color
from kivy.core.window import Window
from kivy.animation import Animation

class Circle(Widget):
    v = NumericProperty(0)

class Illusion(Widget):
    c1 = ObjectProperty(None)
    c2 = ObjectProperty(None)
    c3 = ObjectProperty(None)
    c4 = ObjectProperty(None)

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

        objects = (self.c1, self.c2, self.c3, self.c4)
        values = (0,1,0,0)

        for i, item in enumerate(objects):
            objects[i].v = values[i]

        self.start_illusion(instance = None, value = None)

    def start_illusion(self, instance, value):
        animation = Animation(v = 1, d = .25)
        animation.bind(on_complete=self.continue_illusion)
        animation.start(self.c3)
        animation.start(self.c4)

    def continue_illusion(self, instance, value):
        animation = Animation(v = 0, d = .25)
        animation.bind(on_complete=self.start_illusion)
        animation.start(self.c3)
        animation.start(self.c4)

class IllusionsApp(App):
    Window.clearcolor = (0,0,1,1)
    def build(self):
        return Illusion()

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

我的 .kv 文件：

<Circle>:
    canvas:
        Color:
            hsv: 0,0,self.v
        Ellipse:
            pos: self.pos
            size: self.size

<Illusion>:
    c1: _c1
    c2: _c2
    c3: _c3
    c4: _c4

    Circle:
        id: _c1
        size: 250,250
        center_x: self.parent.width / 4
        center_y: self.parent.height / 2

    Circle:
        id: _c2
        size: 250,250
        center_x: self.parent.width * 3/4
        center_y: self.parent.height / 2

    Circle:
        id: _c3
        size: 180,180
        center_x: self.parent.width / 4
        center_y: self.parent.height / 2

    Circle:
        size: 180,180
        id: _c4
        center_x: self.parent.width * 3/4
        center_y: self.parent.height / 2

Answer 1

我认为问题可能出在每次调用 on_complete 函数时重新创建新的 Animation。

尝试使用repeat animation property.

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

        objects = (self.c1, self.c2, self.c3, self.c4)
        values = (0,1,0,0)

        for i, item in enumerate(objects):
            objects[i].v = values[i]

        self.animation_v0 = Animation(v = 0, d = .25) + Animation(v = 1, d = .25)
        self.animation_v0.repeat = True
        self.animation_v1 = Animation(v = 1, d = .25) + Animation(v = 0, d = .25)
        self.animation_v1.repeat = True

        #self.animation_v0.bind(on_complete=self.start_illusion)
        #self.animation_v1.bind(on_complete=self.continue_illusion)

        self.animation_v0.start(self.c3)
        self.animation_v1.start(self.c4)

    def start_illusion(self, instance, value):
        self.animation_v0.start(self.c3)

    def continue_illusion(self, instance, value):
        self.animation_v1.start(self.c4)

在 Kivy 中同步动画

Animations in the same time in Kivy

python

python-2.7

kivy