Python & tkinter:重叠按钮上的 canvas.lift 和 canvas.lower 不起作用

Python & tkinter: canvas.lift and canvas.lower on overlapping buttons does not work

我使用 tkinter 和 python 3.4 在 canvas 上创建了两个重叠按钮:

现在我想把 button1 放在前面(你现在看不到的按钮,因为它在 button2 下面)

self.canvas.lift(self.button1)

但由于某种原因,这不起作用。只是什么也没发生。降低 button2 也没有效果。你能告诉我为什么吗?

import tkinter as tk

class Example(tk.Frame):
    def __init__(self, root):
        tk.Frame.__init__(self, root)
        self.canvas = tk.Canvas(self, width=400, height=400, background="bisque")
        self.canvas.create_text(50,10, anchor="nw", text="Click to lift button1")
        self.canvas.grid(row=0, column=0, sticky="nsew")
        self.canvas.bind("<ButtonPress-1>", self.click_on_canvas)

        self.button1 = tk.Button(self.canvas, text="button1")        
        self.button2 = tk.Button(self.canvas, text="button2")

        x = 40
        self.canvas.create_window(x, x, window=self.button1)
        self.canvas.create_window(x+5, x+5, window=self.button2)



    def click_on_canvas(self, event):

        print("lifting", self.button1)
        self.canvas.lift(self.button1)
        self.canvas.lower(self.button2)


if __name__ == "__main__":
    root = tk.Tk()
    Example(root).pack(fill="both", expand=True)
    root.mainloop()

无需在 canvas 上调用 lift(),您需要直接在小部件实例上调用它:

def click_on_canvas(self, event):
    print("lifting", self.button1)
    self.button1.lift()
    self.button2.lower()   # Not necessary to both lift and lower

这仅适用于通过 canvas 上的 window 显示的小部件。

如果您要绘制线条或矩形等对象,您可以像以前一样在 canvas 实例上使用 lift()tag_raise()