Kivy动画类用于动画化Kivy图像

Question

Kivy动画类用于动画化Kivy图像

pythonanimationkivy

4

Python 3.4 Kivy 1.10.0

我正在尝试使用Kivy动画类来动画化我的Image类。这是因为我想分别修改每个图像的anim_delay和position值。

我想修改一个image类的'source'属性。虽然它识别了'source'属性，但它会尝试将文件名字符串乘以file。

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'

我看了Kivy代码中的animation.py，发现从上面返回错误的值是:

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

这是否意味着在Kivy代码中没有像我计划中的动画？或者，我该如何解决这个问题，使动画能够正确循环播放？

- Kevin Alvarez

1个回答

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可以查看英文原文，
原文链接

- Yoav Glazner · Accepted Answer

错误发生的原因是动画无法从一个str对象过渡到另一个str对象"image0.png" -> "image1.png"！？解决方法之一是使用on_complete回调函数。

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)

另一个选项是在图像上添加一个名为 image_num 的属性，并进行绑定，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))