如何让球从屏幕顶部中心落到底部

Question

我目前正在开发一个项目，它只显示一个青色球从画布顶部循环移动到画布底部。我不知道我似乎做错了什么，我是 python 和 tkinter 的初学者。感谢您提供的所有帮助。

def moveDown():
    canvas.data.cy += 5
    if (canvas.data.cy + canvas.data.radius \>= canvasWidth ):
        canvas.data.cy = canvas.data.radius

def doTimerFired():
    moveDown()
    redrawAll()

def timerFired():
    doTimerFired()
    delay = canvas.data.delay  # milliseconds
    canvas.after(delay, timerFired) # pause, then call timerFired again

def redrawAll():
    canvas.delete(ALL)

    # draw the circle
    r = canvas.data.radius
    cx = canvas.data.cx
    cy = canvas.data.cy
    canvas.create_oval(cx-r, cy-r, cx+r, cy+r, fill="cyan") 

def init():
    canvas.data.radius = 10  
    canvas.data.cx = 10
    canvas.data.cy = 14
    canvas.data.delay = 100 #milliseconds

def run():
    # create the root and the canvas
    global canvas, canvasWidth, canvasHeight
    root = Tk()
    canvasWidth = 500
    canvasHeight = 500
    canvas = Canvas(root, width=canvasWidth, height=canvasHeight)
    canvas.pack()

    # Set up canvas data and call init
    class Struct: pass
    canvas.data = Struct()
    canvas.data.canvasWidth = canvasWidth
    canvas.data.canvasHeight = canvasHeight
    init()
    timerFired()

    # and launch the app
    root.mainloop()  # This call BLOCKS 

if __name__ == "__main__":
    run()

Answer 1

如何让球从屏幕顶部中心落到 底部。

拼写错误

\>= canvasWidth

应该是

== canvasWidthin moveDown()

函数。

将球从屏幕顶部中心放置到底部。

在第 23 行添加值：

cx = canvas.data.cx

至：

cx = canvas.data.cx+225