Kivy傍教程語法錯誤：無效的語法

Question

蟒蛇2.7.x kivy 1.9.0

我剛剛開始接觸Kivy，通過傍教程去。事情進展順利，但現在我得到了一個非常簡單的錯誤。我無法弄清楚什麼是錯的。

我得到的錯誤是：

File: "C:\Users\toreilly\mystuff\kivypong.py" \n 
    def update(self, dt): 
    ^
SyntaxError: invalid syntax 

的代碼是在這裏：

from kivy.app import App 
from kivy.uix.widget import Widget 
from kivy.properties import NumericProperty, ReferenceListProperty, \ 
    ObjectProperty 
from kivy.vector import Vector 
from kivy.clock import Clock 
from random import randint 


class PongBall(Widget): 
    velocity_x = NumericProperty(0) 
    velocity_y = NumericProperty(0) 
    velocity = ReferenceListProperty(velocity_x, velocity_y) 

    def move(self): 
     self.pos = Vector(*self.velocity) + self.pos 


class PongGame(Widget): 
    ball = ObjectProperty(None) 

    def serve_ball(self): 
     self.ball.center = self.center 
     self.ball.velocity = Vector(4,0).rotate(randint(0,360) 

    def update(self, dt): 
     self.ball.move() 

     #bounce off top and bottom 
     if (self.ball.y < 0) or (self.ball.top > self.height): 
      self.ball.velocity_y *= -1 

     #bounce off left and right 
     if (self.ball.x < 0) or (self.ball.right > self.width): 
      self.ball.velocity_x *= -1 


class PongApp(App): 
    def build(self): 
     game = PongGame() 
     game.serve_ball() 
     Clock.schedule_interval(game.update, 1.0/60.0) 
     return game 


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

我將不勝感激任何和所有的指導。謝謝。

Answer 1

你缺少一個右括號在前面的方法：

def serve_ball(self): 
    self.ball.center = self.center 
    self.ball.velocity = Vector(4,0).rotate(randint(0,360)) # HERE 

def update(self, dt): 
    self.ball.move()