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Kivy函数调用中出现意外的TypeError

typeerror kivy python

raggot · 技术社区 · 5 年前

我将Kivy与python3.5结合使用。我正在试着设置一个应用程序,在这个应用程序中按下按钮可以安排函数调用。前提:这是我第一次使用Kivy,我对Python不是很在行。下面是我的简化代码:

class MyApp(App):
    def build(self):
        layout = GridLayout(cols=2)
        TextStream = Label(text = 'Something will be written here: ')
        StartButton = Button(text = 'Start writing')
        StartButton.bind(on_press=lambda x:self.start_program(freq=10))
        layout.add_widget(TextStream)
        layout.add_widget(StartButton)
        return layout

    def start_program(self, freq):
        Clock.schedule_interval(self.write_something, 1.0/freq)
        # Also tried Clock.schedule_interval(self.write_something(), 1.0/freq)

    def write_something(self):
        TextStream.text =+ 'Something '

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

运行脚本时得到的结果是:

TypeError: write_something() takes 1 positional argument but 2 were given

阅读答案 this question ,关于这个特定的错误,我理解Python中的方法实际上是以不同的方式实现的,而不是它们在代码中的显示方式。

更准确地说,从 this comment 我理解正确声明方法 write_something 给它 self this answer

那么,有没有一些沉默的争论通过了基维?我是不是用错误的方法调用了这个方法?

编辑-错误堆栈

Traceback (most recent call last):

  File "<ipython-input-1-5d17b5569154>", line 1, in <module>
    runfile('/home/raggot/Projects/MyApp/scripts/_test_kivy.py', wdir='/home/raggot/Projects/MyApp/scripts')

  File "/usr/local/lib/python3.5/dist-packages/spyder/utils/site/sitecustomize.py", line 705, in runfile
    execfile(filename, namespace)

  File "/usr/local/lib/python3.5/dist-packages/spyder/utils/site/sitecustomize.py", line 102, in execfile
    exec(compile(f.read(), filename, 'exec'), namespace)

  File "/home/raggot/Projects/MyApp/scripts/_test_kivy_camera.py", line 78, in <module>
    MyApp().run()

  File "/usr/local/lib/python3.5/dist-packages/kivy/app.py", line 826, in run
    runTouchApp()

  File "/usr/local/lib/python3.5/dist-packages/kivy/base.py", line 502, in runTouchApp
    EventLoop.window.mainloop()

  File "/usr/local/lib/python3.5/dist-packages/kivy/core/window/window_pygame.py", line 403, in mainloop
    self._mainloop()

  File "/usr/local/lib/python3.5/dist-packages/kivy/core/window/window_pygame.py", line 289, in _mainloop
    EventLoop.idle()

  File "/usr/local/lib/python3.5/dist-packages/kivy/base.py", line 337, in idle
    Clock.tick()

  File "/usr/local/lib/python3.5/dist-packages/kivy/clock.py", line 581, in tick
    self._process_events()

  File "kivy/_clock.pyx", line 384, in kivy._clock.CyClockBase._process_events

  File "kivy/_clock.pyx", line 414, in kivy._clock.CyClockBase._process_events

  File "kivy/_clock.pyx", line 412, in kivy._clock.CyClockBase._process_events

  File "kivy/_clock.pyx", line 167, in kivy._clock.ClockEvent.tick

TypeError: write_something() takes 1 positional argument but 2 were given

1 回复 | 直到 5 年前

raggot 5 年前

schedule_interval Kivy传递额外的参数给它,因此它抛出错误,在你的情况下它只使用 args 你没有任何问题。如果是 Clock ,它通过了 dt

def start_program(self, freq):
    Clock.schedule_interval(self.write_something, 1.0/freq)

def write_something(self, *args):
    print(args)