Kivy 动画类为 Kivy 图像设置动画

Question

Python 3.4 Kivy 1.10.0

我正在尝试使用 Kivy Animation 类为我的 Image 类设置动画。这是因为我想分别修改每张图像的 anim_delay 和 position 值。

我想修改图像类的“源”属性。尽管它可以识别“源”属性，但它会尝试将文件名字符串文件相乘。

如何修改图片文件名？

工作示例：

from kivy.app import App
from kivy.animation import Animation
from kivy.clock import Clock
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.uix.image import Image

class Test(App):
    def __init__(self, **kwargs):
        super(Test, self).__init__(**kwargs)

        self.content = BoxLayout()
        self.content.orientation = 'vertical' 
        self.anim_image = Image(source = 'image1.png')
        self.anim_button = Button(on_press=self.animate_image)
        self.content.add_widget(self.anim_image)
        self.content.add_widget(self.anim_button)

    def build(self):
        return self.content

    def animate_image(self, *args, **kwargs):
        image_animate = Animation()
        for i in range(4):
            image_animate += Animation(x = (i + 10), source = 'image' + str(i) + '.png', duration=(0.10 * i))
        image_animate.start(self.anim_image)


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

错误日志：

[INFO   ] [Base        ] Leaving application in progress...
 Traceback (most recent call last):
   File "C:\Python34x86\projects\rogue_like_app\repeatable issues\animation_image_source.py", line 31, in <module>
     Test().run()
   File "C:\Python34x86\lib\site-packages\kivy\app.py", line 828, in run
     runTouchApp()
   File "C:\Python34x86\lib\site-packages\kivy\base.py", line 504, in runTouchApp
     EventLoop.window.mainloop()
   File "C:\Python34x86\lib\site-packages\kivy\core\window\window_sdl2.py", line 663, in mainloop
     self._mainloop()
   File "C:\Python34x86\lib\site-packages\kivy\core\window\window_sdl2.py", line 405, in _mainloop
     EventLoop.idle()
   File "C:\Python34x86\lib\site-packages\kivy\base.py", line 339, in idle
     Clock.tick()
   File "C:\Python34x86\lib\site-packages\kivy\clock.py", line 581, in tick
     self._process_events()
   File "kivy\_clock.pyx", line 367, in kivy._clock.CyClockBase._process_events (kivy\_clock.c:7700)
   File "kivy\_clock.pyx", line 397, in kivy._clock.CyClockBase._process_events (kivy\_clock.c:7577)
   File "kivy\_clock.pyx", line 395, in kivy._clock.CyClockBase._process_events (kivy\_clock.c:7498)
   File "kivy\_clock.pyx", line 167, in kivy._clock.ClockEvent.tick (kivy\_clock.c:3490)
   File "C:\Python34x86\lib\site-packages\kivy\animation.py", line 345, in _update
     value = calculate(a, b, t)
   File "C:\Python34x86\lib\site-packages\kivy\animation.py", line 376, in _calculate
     return (a * (1. - t)) + (b * t)
 TypeError: can't multiply sequence by non-int of type 'float'

查看 Kivy Code 中的 animation.py，我发现从上面返回错误的值是：

a = image2.png
b = image1.png
t = 0.0

这是否意味着这不是 Kivy 代码固有的动画？或者，我该如何解决这个问题，以便动画能够正确循环播放？

Answer 1

发生错误是因为 动画 无法从 str 对象过渡到 str 对象 "image0.png" -> "image1.png" !?

解决此问题的一种方法是使用 on_complete 回调

def animate_image(self, *args, **kwargs):
    image_animate = Animation()

    def f(i, w):
        w.source = 'image%d.jpg' % i


    for i in range(4):

        a = Animation(x = (i + 10), duration=(0.10 * i),
                      )
        a.on_complete = functools.partial(f, i)


        image_animate += a

    image_animate.start(self.anim_image)

另一种选择是在图像上具有 image_num 属性并绑定它，以便相应地更改图像...

例如在KV文件中：

<MyImage>:
    image_num: 0
    source: "image%d.png" % int(self.image_num)

在 .py 文件中：

image_animate += Animation(x = (i + 10), image_num=i, duration=(0.10 * i))