Python：“ NoneType”对象没有属性“ get”

如何解决Python：“ NoneType”对象没有属性“ get”

我正在使用tkinter在python中创建GUI，并且在运行它时遇到了麻烦。我有一个输入框小部件，一个单选按钮小部件和一个按钮小部件。当我按下按钮时，我想要的是用户在输入框中键入数字，然后从单选按钮列表中选择一个选项。当用户按下按钮时，我希望检索这些值并将其显示在另一个框架中进行测试。我得到的是，当按下按钮时，出现错误'NoneType' object has no attribute 'get'。错误是指输入框内的值：self.tune_entry

我的代码如下：

SA_main.py

import os
import tkinter as tk
from tkinter import ttk
from tkinter import font
import SA_gui

def main():

    x_vals = [0,1,2,3,4]
    y_vals = [0,4]

    root = SA_gui.tk.Tk()
    UI = SA_gui.Window(root,x_vals,y_vals)

    root.mainloop()


if __name__ == "__main__":
    main()

SA_gui.py

import os
import tkinter as tk
from tkinter import ttk
from tkinter import font

# Class to define,setup,and build the GUI
class Window:

    # Dimensions of the GUI
    HEIGHT = 600
    WIDTH = 1200

    # Colors for main layout
    bg_color = "#B0E0E6"
    frame_color1 = "#73B1B7"
    white_color = "#FFFFFF"

    def __init__(self,master,y_vals):

        # Take in the lists of files for later use
        self.x_vals = x_vals
        self.y_vals = y_vals

        #--------------------------------------------------------------

        # Define and create the window
        self.master = master
        master.title("Signal Analysis")
        master.geometry("{}x{}".format(Window.WIDTH,Window.HEIGHT))

        # Create and place the background frame
        self.bg_frame = tk.Frame(self.master,bg=Window.bg_color,bd=5)
        self.bg_frame.place(relwidth=1,relheight=1)

        # Create the main title
        self.main_title = tk.Label(self.bg_frame,text="Software Defined Radio Signal Analysis",font=("Courier",14))
        self.main_title.pack(side="top")

        #--------------------------------------------------------------

        # Create and place the frame for tuning
        self.tune_frame = tk.Frame(self.bg_frame,bg=Window.frame_color1,bd=4)
        self.tune_frame.place(relx=0.05,rely=0.1,relwidth=0.2428,relheight=0.8)

        # Create and place the title for the tuning frame
        self.tune_title = tk.Label(self.tune_frame,text="Tune",font= 
            ("Courier",11))
        self.tune_title.place(relwidth=1,anchor="nw")

        # Create and place the contents of the tuning frame
        self.tune_cont = tk.Frame(self.tune_frame,bg=Window.white_color,bd=4)
        self.tune_cont.place(relx=0.05,rely=0.05,relwidth=0.9,relheight=0.925)

        #Label for frequency entry
        self.tune_label = tk.Label(self.tune_cont,text='Enter carrier frequency: (kHz)',bg=Window.white_color)
        self.tune_label.place(relx=0.025,rely=0)

        #Entry Box for frequency entry
        self.tune_entry = tk.Entry(self.tune_cont)
        self.tune_entry.place(relx=0.025,rely=0.075,relwidth=0.95,relheight=0.05)

        #Label for divider
        self.tune_div = ttk.Separator(self.tune_cont,orient="horizontal")
        self.tune_div.place(rely=0.175,relwidth=1)

        #Label for display mode
        self.disp_label = tk.Label(self.tune_cont,text='Select Display:',bg=Window.white_color)
        self.disp_label.place(relx=0.025,rely=0.2)

        #Variable for radiobuttons
        self.var = tk.IntVar(self.tune_cont).set("1")

        #Radio Button for Spectral Analysis
        self.SA_select = tk.Radiobutton(self.tune_cont,text="Spectral 
            Analysis",padx=20,variable=self.var,value=1)
        self.SA_select.place(relx=0.025,rely=0.275)

        #Radio Button for Option 2
        self.opt2_select = tk.Radiobutton(self.tune_cont,text="Option 2",value=2)
        self.opt2_select.place(relx=0.025,rely=0.35)

        #Radio Button for Option 3
        self.opt3_select = tk.Radiobutton(self.tune_cont,text="Option 3",value=3)
        self.opt3_select.place(relx=0.025,rely=0.425)


        #Button for selection
        self.tune_button = ttk.Button(self.tune_cont,text="Enter",command=lambda: 
            self.print_selected(self.var.get(),self.tune_entry.get()))
        self.tune_button.place(relx= 0.775,rely=0.9,relwidth=0.2,relheight=0.075)

        #-----------------------------------------------------------------

        # Create and place the frame for the plot
        self.plot_frame = tk.Frame(self.bg_frame,bd=4)
        self.plot_frame.place(relx=0.3428,relwidth=0.6071,relheight=0.8)

        # Create and place the title for the plot frame
        self.plot_title = tk.Label(self.plot_frame,text="Plot",11))
        self.plot_title.place(relwidth=1,anchor="nw")

        # Create and place the contents of the plot frame
        self.plot_cont = tk.Frame(self.plot_frame,bd=4)
        self.plot_cont.place(relx=0.025,relheight=0.925)



    def print_selected(self,disp,freq):
        if disp == 1:
            disp_mode = "Spectral Analysis"
        elif disp == 2:
            disp_mode = "Option 2"
        else:
            disp_mode = "Option 3"

        #Label for this test
        self.prnt_label = tk.Label(self.plot_cont,text="Display: " + disp_mode + ",Center Freq: " + 
            freq,bg=Window.white_color)
        self.prnt_label.place(relx=0.025,rely=0.2)

感谢您为解决此问题提供的任何帮助！

解决方法

考虑以下代码：

self.var = tk.IntVar(self.tune_cont).set("1")

每次执行x=y().z()时，python都会将z()的返回值分配给x。因此，在您的代码中，您将.set("1")的结果辅助为self.var。 set方法将返回None，因此self.var为None。因此，当您以后尝试调用self.var.get()时，就和None.get()一样。

如果要在创建时初始化变量，则无需调用set。另外，虽然它可以传递字符串，但是如果您要设置IntVar，则应该将其设置为整数。

self.var = tk.IntVar(value=1)