一个Python的GUI为什么出错？

Question

from tkinter import *
import random
from math import *
from tkinter import messagebox

from pefile import b


class Application(Frame):

    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.pack()
        self.createWidget()

    def createWidget(self):
        a = StringVar()
        b = StringVar()
        c = StringVar()
        
        self.label01 = Label(self, text="二次项系数：").grid(row=0, column=0)
        self.entry01 = Entry(self, textvariable=a).grid(row=0, column=1)

        self.label02 = Label(self, text="一次项系数：").grid(row=1, column=0)
        self.entry02 = Entry(self, textvariable=b).grid(row=1, column=1)
        
        self.label03 = Label(self, text="常数项系数：").grid(row=2, column=0)
        self.entry03 = Entry(self, textvariable=c).grid(row=2, column=1)

        Button(self, text="计算", command=self.jisuan).grid(row=3, column=1, sticky=EW)
        Button(self, text="退出").grid(row=3, column=2, sticky=E)

        self.label04 = Label(self, text="请先将方程的右端化为0").grid(row=4, sticky=EW)
    
    def jisuan(self):
        aa = self.label01.get()
        bb = self.label01.get()
        cc = self.label01.get()
        print(aa)
        d = int((bb)**2-4*(aa)*(cc))
        if d < 0:
            messagebox.showinfo("计算结果","此二次方程无实数根")
        elif d == 0:
            outcome = -b/(2*aa)
            messagebox.showinfo("计算结果","方程有且仅有一个实数根：%d" % outcome)
        elif d > 0:
            x1 = (-b + sqrt(d))/(2*aa)
            x2 = (-b - sqrt(d))/(2*aa)
            messagebox.showinfo("计算结果","方程有两个实数根，分别为：%d和%d" % (x1, x2))



if __name__=='__main__':
    root=Tk()
    root.geometry("400x300+200+300")
    app=Application(master=root)
    root.mainloop()


input()

Answer 1

改了一下代码，界面运行正常，排除了代码中错误，但是其计算部分你看一下再作调整。

from tkinter import *
import random
from math import *
from tkinter import messagebox

#from pefile import b


class Application(Frame):

    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.pack()
        self.createWidget()

    def createWidget(self):
        a = StringVar()
        b = StringVar()
        c = StringVar()

        self.label01 = Label(self, text="二次项系数：").grid(row=0, column=0)
        self.entry01 = Entry(self, textvariable=a)
        self.entry01.grid(row=0, column=1)

        self.label02 = Label(self, text="一次项系数：").grid(row=1, column=0)
        self.entry02 = Entry(self, textvariable=b)
        self.entry02.grid(row=1, column=1)

        self.label03 = Label(self, text="常数项系数：").grid(row=2, column=0)
        self.entry03 = Entry(self, textvariable=c)
        self.entry03.grid(row=2, column=1)

        Button(self, text="计算", command=self.jisuan).grid(
            row=3, column=1, sticky=EW)
        Button(self, text="退出",command=self.quit).grid(row=3, column=2, sticky=E)

        self.label04 = Label(self, text="请先将方程的右端化为0").grid(row=4, sticky=EW)

    def jisuan(self):
        aa = self.entry01.get()
        bb = self.entry02.get()
        cc = self.entry03.get()
        print(aa)
        d = float((int(bb)**2-4*(int(aa)*int(cc))))
        if d < 0:
            messagebox.showinfo("计算结果", "此二次方程无实数根")
        elif d == 0:
            outcome = -b/(2*aa)
            messagebox.showinfo("计算结果", "方程有且仅有一个实数根：%d" % outcome)
        elif d > 0:
            x1 = (-b + sqrt(d))/(2*aa)
            x2 = (-b - sqrt(d))/(2*aa)
            messagebox.showinfo("计算结果", "方程有两个实数根，分别为：%d和%d" % (x1, x2))


if __name__ == '__main__':
    root = Tk()
    root.geometry("400x300+200+300")
    app = Application(master=root)
    root.mainloop()

Answer 2

错误在于self.entry01 = Entry(self, textvariable=a).grid(row=0, column=1)，加上grid后就变成了None类型，将其拆分为两行：

self.entry01 = Entry(self, textvariable=a)

self.entry01.grid(row=0, column=1)

后面的aa写成：aa = self.entry01.get()

其他的如bb,cc，如有调用获取其值的，作相同处理。

 

Answer 3

贴一下错误信息，更好分析原因。

Answer 4

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