Question

我想删除画布上的所有内容。我认为canvas.delete(tk.ALL)是个不错的选择。但是它不起作用。为什么？加速器也不起作用。

 import tkinter as tk

class Graphy(tk.Frame):
    def __init__(self,parent):
        tk.Frame.__init__(self,parent)
        self.parent = parent
        self.parent.title("Graphy 0.1")
        self.initialize()

    def initialize(self):

        #Toolbar
        toolbar = tk.Frame(self.parent)
        toolbar.pack(side=tk.TOP, fill=tk.X)
        knotbtn=tk.Button(toolbar, text="o")
        knotbtn.pack(side=tk.LEFT, padx=2, pady=2)
        edgebtn=tk.Button(toolbar, text="/")
        edgebtn.pack(side=tk.LEFT, padx=2, pady=2)


        #Canvas
        self.canvas = tk.Canvas(self.parent, height=600, width=600, bg="white")
        self.canvas.pack()

        #Menue
        menu = tk.Menu(self.parent)
        self.parent.config(menu=menu)

        filemenu = tk.Menu(menu)
        menu.add_cascade(label="Datei", menu=filemenu)
        filemenu.add_command(label= "Neu", command=self.canvas.delete(tk.ALL), accelerator="Strg+N")
        filemenu.add_separator()
        filemenu.add_command(label="Beenden", command=root.quit, accelerator="Strg+Q")

        sightmenu = tk.Menu(menu)
        menu.add_cascade(label="Ansicht", menu=sightmenu)
        sightmenu.add_command(label="Farbe waehlen")

        helpmenu = tk.Menu(menu)
        menu.add_cascade(label="Hilfe", menu=helpmenu)
        helpmenu.add_command(label="Ueber")

        root.bind_all("<Ctrl-N>",self.canvas.delete(tk.ALL))
        root.bind_all("<Ctrl-Q>",root.quit())

        self.state = 0
        self.selected = None
        self.start_x = 0
        self.start_y = 0

        def newKnotornewEdge(event):
            #if button "o" is pressed, every click on the canvas results in a circle
            if self.state == 0:
                self.canvas.create_oval(event.x-25,event.y-25,event.x+25, event.y+25, fill="blue")
                self.canvas.create_text(event.x, event.y, text="A", fill="white")
            #if button "/" is pressed, and two circles are selected, draw a line between them
            elif self.state == 1:
                if self.canvas.itemcget(self.canvas.find_overlapping(event.x, event.y, event.x, event.y), "fill") == "blue" and self.selected == None:
                    self.selected = 1
                    self.start_x = event.x
                    self.start_y = event.y
                elif self.canvas.itemcget(self.canvas.find_overlapping(event.x, event.y, event.x, event.y), "fill") == "blue" and self.selected == 1:
                    self.canvas.create_line(self.start_x, self.start_y, event.x, event.y)
                    self.selected = None
                    self.start_x = 0
                    self.start_y = 0
                elif self.canvas.itemcget(self.canvas.find_overlapping(event.x, event.y, event.x, event.y), "fill") != "blue" and self.selected == 1:
                    self.selected = None
                    self.start_x = 0 
                    self.start_y = 0                     
        self.canvas.bind("<Button -1>", newKnotornewEdge)


        def knotbtnclick(event):
            knotbtn.config(relief = tk.SUNKEN, state=tk.DISABLED)
            edgebtn.config(relief = tk.RAISED, state=tk.ACTIVE)
            self.state = 0
        knotbtn.bind("<Button-1>", knotbtnclick)


        def edgebtnclick(event):
            knotbtn.config(relief = tk.RAISED, state=tk.ACTIVE)
            edgebtn.config(relief = tk.SUNKEN, state=tk.DISABLED)
            self.state = 1
        edgebtn.bind("<Button-1>", edgebtnclick)


root = tk.Tk()
app = Graphy(root)

root.mainloop()

python-tkinter-删除画布

0 个答案: