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我正在尝试使用 Tkinter 编写一个蛇游戏程序 我的蛇由下面定义的圆圈列表组成。但是，当我调用 move 方法时，最后一个不会移动。问题是什么？

    class Circle:

   def __init__(self,canv,x,y,index,direc):
        self._x = x
        self._y = y
        self._index = index
        self._direction = direc
        self._canvas = canv
        coordinat = (self._x)-5,(self._y)-5,(self._x)+5,(self._y)+5

        if index==0:
            color = "gold"
        else:
            color = "green"

        self._circle = canv.create_oval(coordinat ,fill=color, tags=str(self._index))

   def _move(self):
      if self._direction == "up":
         delta = (0,-5)
      elif self._direction == "down":
         delta = (0,5)
      elif self._direction == "left":
         delta = (-5,0)
      elif self._direction == "right":
         delta = (5,0)

      tag = str(self._index)
      self._canvas.move(tag, delta[0],delta[1])

她就是我所说的

self._canvas = Canvas(self._playArea,width=750,height=450,bg="#1C1C1C")
    x = int(self._parent.winfo_width() / 4.)
    y = int(self._parent.winfo_height()/ 4.)
    circle = Circle(self._canvas,x,y,0,"right")
    self._circleList.append(circle)
    self._addCircle()
    self._addCircle()
    self._addCircle()
    self._addCircle()
    self._addCircle()

    self._canvas.place(x=0, y=0)

    for i in range(0,500):
       for x in self._circleList:
          x._move()
          root.update()
          root.after(10)

这是 addCircle 方法

length = len(self._circleList)
    if self._circleList[length-1]._direction == "right":
        x = (self._circleList[length-1]._x)-10
        y = self._circleList[length-1]._y
        d = "right"
    elif self._circleList[length-1]._direction == "left":
        x = (self._circleList[length-1]._x) + 10
        y = self._circleList[length-1]._y
        d = "left"
    elif self._circleList[length-1]._direction == "up":
        x = self._circleList[length-1]._x
        y = (self._circleList[length-1]._y)+10
        d = "up"
    elif self._circleList[length-1]._direction == "down":
        x = self._circleList[length-1]._x
        y = (self._circleList[length-1]._y)-10
        d = "down"

    newCircle = Circle(self._canvas,x,y,length,d)
    self._circleList.append(newCircle)
4

2 回答 2

1

问题是您正在创建第一个项目index=0，然后使用它index作为标签来识别项目。你不应该使用整数作为标签，它是为项目的 id 保留的，但是，你毕竟可以使用它。除了0被 Tcl 评估为 false 之外，因此您没有有效地为它定义任何标签。事实证明，当您打电话时，canvas.move(0, ...)您不会移动任何创建的圆圈。但是您创建的下一个项目被分配了一个标签“1”，当您调用时，canvas.move(1, ...)您实际上是在移动您之前创建的项目（具有“金色”颜色的项目），因为它被 Tcl 自动分配了 id“1”。对创建的所有其他圆圈重复此操作。

解决它的快速方法是更改index + 1​​用于您传递的所有这些索引的代码。但是您包含的代码中有几个问题，所以这是一个修改后的代码，可以执行您所追求的：

import Tkinter

UP, RIGHT, DOWN, LEFT = range(4)

class Circle:
    def __init__(self, canv, x, y, direc, color):
        self.x, self.y = x, y
        self.direction = direc

        self._canvas = canv
        coord = (self.x)-5, (self.y)-5, (self.x)+5, (self.y)+5
        self._index = canv.create_oval(coord, fill=color)

    def move(self):
        y_sign = 1 if self.direction == DOWN else -1
        x_sign = 1 if self.direction == RIGHT else -1
        if self.direction in (UP, DOWN):
            delta = (0, y_sign * 5)
        else:
            delta = (x_sign * 5, 0)
        self._canvas.move(self._index, delta[0], delta[1])


def add_circle(canvas, l):
    d = l[-1].direction
    if d in (UP, DOWN):
        x = l[-1].x
        y = (1 if d == UP else -1) * 10 + l[-1].y
    else:
        x = (1 if d == LEFT else -1) * 10 + l[-1].x
        y = l[-1].y

    circle = Circle(canvas, x, y, d, "green")
    l.append(circle)


def move_circles(circle_l, root):
    for c in circle_l:
        c.move()
    root.after(50, lambda: move_circles(circle_l, root))

root = Tkinter.Tk()
width, height = 750, 450

canvas = Tkinter.Canvas(width=width, height=height, bg="#1C1C1C")
canvas.pack(fill=None, expand=False)

circle_l = []
circle = Circle(canvas, width / 4, height / 4, RIGHT, "gold")
circle_l.append(circle)
for _ in range(5):
    add_circle(canvas, circle_l)

move_circles(circle_l, root)

root.mainloop()
于 2013-01-20T21:51:39.393 回答
0

不是一个真正的答案，但你可以让你的最后一段代码更短/更高效：

length = len(self._circleList)
    x = self._circleList[length-1]._x
    y = self._circleList[length-1]._y
    d = self._circleList[length-1]._direction

    if d == "right":
        x -= 10
    elif d == "left":
        x += 10
    elif d == "up":
        y += 10
    elif d == "down":
        y -= 10

    newCircle = Circle(self._canvas,x,y,length,d)
    self._circleList.append(newCircle)

首先设置默认值，然后只修改x或y如果必须修改。

于 2013-01-21T09:30:31.897 回答