修改代码以拖动字符串

Question

我一直试图理解我从Bryan Oakley here遇到的代码。目前，此代码允许用户使用tkinter拖动两个椭圆。我希望能够修改此代码，以便用户能够从两个列表中拖动字符串（键值对）而不是椭圆形，并匹配它们。例如，我希望用户能够拖动像＆＃34; User＆＃34;从一个列表和＆＃34; Ryan＆＃34;从另一个列表中匹配它们。我非常感谢有关如何修改代码的任何输入，以便用户能够拖动两个字符串。

import Tkinter as tk

class SampleApp(tk.Tk):
    '''Illustrate how to drag items on a Tkinter canvas'''

    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)

        # create a canvas
        self.canvas = tk.Canvas(width=400, height=400)
        self.canvas.pack(fill="both", expand=True)

        # this data is used to keep track of an 
        # item being dragged
        self._drag_data = {"x": 0, "y": 0, "item": None}

        # create a couple movable objects
        self._create_token((100, 100), "white")
        self._create_token((200, 100), "black")

        # add bindings for clicking, dragging and releasing over
        # any object with the "token" tag
        self.canvas.tag_bind("token", "<ButtonPress-1>", self.OnTokenButtonPress)
        self.canvas.tag_bind("token", "<ButtonRelease-1>", self.OnTokenButtonRelease)
        self.canvas.tag_bind("token", "<B1-Motion>", self.OnTokenMotion)

    def _create_token(self, coord, color):
        '''Create a token at the given coordinate in the given color'''
        (x,y) = coord
        self.canvas.create_oval(x-25, y-25, x+25, y+25, 
                                outline=color, fill=color, tags="token")

    def OnTokenButtonPress(self, event):
        '''Being drag of an object'''
        # record the item and its location
        self._drag_data["item"] = self.canvas.find_closest(event.x, event.y)[0]
        self._drag_data["x"] = event.x
        self._drag_data["y"] = event.y

    def OnTokenButtonRelease(self, event):
        '''End drag of an object'''
        # reset the drag information
        self._drag_data["item"] = None
        self._drag_data["x"] = 0
        self._drag_data["y"] = 0

    def OnTokenMotion(self, event):
        '''Handle dragging of an object'''
        # compute how much this object has moved
        delta_x = event.x - self._drag_data["x"]
        delta_y = event.y - self._drag_data["y"]
        # move the object the appropriate amount
        self.canvas.move(self._drag_data["item"], delta_x, delta_y)
        # record the new position
        self._drag_data["x"] = event.x
        self._drag_data["y"] = event.y

if __name__ == "__main__":
    app = SampleApp()
    app.mainloop()

Answer 1

这就是你要找的东西：

import tkinter as tk

class SampleApp(tk.Tk):
    '''Illustrate how to drag items on a Tkinter canvas'''

    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)

        # create a canvas
        self.canvas = tk.Canvas(width=400, height=400, bg='red')
        self.canvas.pack(fill="both", expand=True)

        # this data is used to keep track of an 
        # item being dragged
        self._drag_data = {"x": 0, "y": 0, "item": None}

        # create a couple movable objects
        self._create_token((100, 100), "white", "User")
        self._create_token((200, 100), "black", "Ryan")

        # add bindings for clicking, dragging and releasing over
        # any object with the "token" tag
        self.canvas.tag_bind("token", "<ButtonPress-1>", self.OnTokenButtonPress)
        self.canvas.tag_bind("token", "<ButtonRelease-1>", self.OnTokenButtonRelease)
        self.canvas.tag_bind("token", "<B1-Motion>", self.OnTokenMotion)

    def _create_token(self, coord, color, mytext):
        '''Create a token at the given coordinate in the given color'''
        (x,y) = coord
        self.canvas.create_text(x-25, y-25,  
                                fill=color, tags="token", text=mytext)

    def OnTokenButtonPress(self, event):
        '''Being drag of an object'''
        # record the item and its location
        self._drag_data["item"] = self.canvas.find_closest(event.x, event.y)[0]
        self._drag_data["x"] = event.x
        self._drag_data["y"] = event.y

    def OnTokenButtonRelease(self, event):
        '''End drag of an object'''
        # reset the drag information
        self._drag_data["item"] = None
        self._drag_data["x"] = 0
        self._drag_data["y"] = 0

    def OnTokenMotion(self, event):
        '''Handle dragging of an object'''
        # compute how much this object has moved
        delta_x = event.x - self._drag_data["x"]
        delta_y = event.y - self._drag_data["y"]
        # move the object the appropriate amount
        self.canvas.move(self._drag_data["item"], delta_x, delta_y)
        # record the new position
        self._drag_data["x"] = event.x
        self._drag_data["y"] = event.y

if __name__ == "__main__":
    app = SampleApp()
    app.mainloop()

？

我改变了什么：
（编辑线：10,18,19,27,30和31）
- 从默认（白色）到红色的背景颜色，以更好地识别白色和黑色物体;
- self.canvas.create_oval到self.canvas.create_text因为你想要字符串而不是椭圆形;
- 另外，删除了第二对坐标（x+25, y+25），因为create_text只需要 一对坐标（create_oval需要两个它们已被删除outline=color，因为文本对象没有outline选项，因此Tkinter会返回unknown option错误;
- 最后，在将其从create_oval更改为create_text后，我必须将text选项mytext添加到_create_token函数（def _create_token(self, coord, color, mytext): ）及其对可移动物体的实例（＆＃34;用户＆＃34;＆amp;＆＃34; Ryan＆＃34;）：
self._create_token((100, 100), "white", "User") self._create_token((200, 100), "black", "Ryan")。