如何使用 tkinter 更新框架？

Question

我使用 tkinter 创建了两个框架。在名为StarterPage 的第一帧中，有一个执行该功能的按钮：

estrazioneCanzoni(sp, codice_playlist_piaciute, codice_playlist_non_piaciute)

哪里有这个声明：

global scoreDecisionTree, scoreKnn, scoreRandomForest, scoreKmeans

我用一些值来评估前面的变量。我已经检查了全局变量的评估是否可以使用控制台打印它们。

该按钮还会打开PageOne 框架。问题是PageOne 框架显示为scoreDecisionTree、scoreKnn、scoreRandomForest 和scoreKmeans:None 的值，而不是我在控制台中打印它们时可以看到的实际值，而不是使用 tkinter gui。我认为问题在于 PageOne 框架是在开始时创建的并且从未更新过。我该如何解决？

scoreDecisionTree=None
scoreKnn=None
scoreRandomForest=None
scoreKmeans=None

class SampleApp(tk.Tk):

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

        self.title_font = tkfont.Font(family='Helvetica', size=18, weight="bold", slant="italic")

        container = tk.Frame(self)
        container.pack(side="top", fill="both", expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)

        self.frames = {}
        self.frames["StartPage"] = StartPage(parent=container, controller=self)
        self.frames["PageOne"] = PageOne(parent=container, controller=self)


        self.frames["StartPage"].grid(row=0, column=0, sticky="nsew")
        self.frames["PageOne"].grid(row=0, column=0, sticky="nsew")


        self.show_frame("StartPage")

    def show_frame(self, page_name):
        '''Show a frame for the given page name'''
        frame = self.frames[page_name]
        frame.tkraise()


class StartPage(tk.Frame):

    def __init__(self, parent, controller):
        sp=login()
        tk.Frame.__init__(self, parent)
        self.controller = controller
        label = tk.Label(self, text="ID playlist canzoni piaciute", font = "Times 15")
        label.pack(side="top", fill="x", pady=10)

        self.entry1 = tk.Entry(self, width=30)
        self.entry1.pack(side="top", fill="x", pady=10)

        label = tk.Label(self, text="ID playlist canzoni non piaciute",font = "Times 15")
        label.pack(side="top", fill="x", pady=10)

        self.entry2 = tk.Entry(self, width=30)
        self.entry2.pack(side="top", fill="x", pady=10)

        def parametri():
            estrazioneCanzoni(sp, self.entry1.get(), self.entry2.get())
            controller.show_frame("PageOne")

        button1 = tk.Button(self, text="Analizza",
                            command= lambda: parametri())

        button1.pack()


class PageOne(tk.Frame):

    def __init__(self, parent, controller):

        tk.Frame.__init__(self, parent)
        self.controller = controller
        label = tk.Label(self, text="Accuratezza", font=controller.title_font)
        label.pack(side="top", fill="x", pady=10)
        label1 = tk.Label(self, font="Times 12" )
        label1.pack(side="top", fill="x", pady=10)
        label1.config(text = "Decision tree: {}".format(scoreDecisionTree))
        label2 = tk.Label(self, font="Times 12" )
        label2.pack(side="top", fill="x", pady=10)
        label2.config(text = "Knn: {}".format(scoreKnn))
        label3 = tk.Label(self, font="Times 12" )
        label3.pack(side="top", fill="x", pady=10)
        label3.config(text = "Random forest: {}".format(scoreRandomForest))
        label4 = tk.Label(self, font="Times 12" )
        label4.pack(side="top", fill="x", pady=10)
        label4.config(text = "Kmeans: {}".format(scoreKmeans))


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

Answer 1

将PageOne label.config 调用移动到PageOne.update_globals 方法中：

def update_globals(self):
    self.label1.config(text="Decision tree: {}".format(scoreDecisionTree))
    self.label2.config(text="Knn: {}".format(scoreKnn))
    self.label3.config(text="Random forest: {}".format(scoreRandomForest))
    self.label4.config(text="Kmeans: {}".format(scoreKmeans))

并创建一个StartApp.update_globals 方法，该方法将方法调用发送到全局变量更改时需要更新的所有帧：

def update_globals(self):
    frame = self.frames["PageOne"]
    frame.update_globals()

然后在parametri 内调用StartPage controller.update_globals()：

def parametri():
    estrazioneCanzoni(sp, self.entry1.get(), self.entry2.get())
    controller.update_globals()
    controller.show_frame("PageOne")

因此，每当按下Analizza 按钮时，estrazioneCanzoni 都会更改全局变量， 而controller.update_globals() 处理PageOne 中标签的设置。

---

import tkinter as tk
from tkinter import font as tkfont

scoreDecisionTree = None
scoreKnn = None
scoreRandomForest = None
scoreKmeans = None


class SampleApp(tk.Tk):

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

        self.title_font = tkfont.Font(
            family='Helvetica', size=18, weight="bold", slant="italic")

        container = tk.Frame(self)
        container.pack(side="top", fill="both", expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)

        self.frames = {}
        self.frames["StartPage"] = StartPage(parent=container, controller=self)
        self.frames["PageOne"] = PageOne(parent=container, controller=self)

        self.frames["StartPage"].grid(row=0, column=0, sticky="nsew")
        self.frames["PageOne"].grid(row=0, column=0, sticky="nsew")

        self.show_frame("StartPage")

    def show_frame(self, page_name):
        '''Show a frame for the given page name'''
        frame = self.frames[page_name]
        frame.tkraise()

    def update_globals(self):
        frame = self.frames["PageOne"]
        frame.update_globals()

class StartPage(tk.Frame):

    def __init__(self, parent, controller):
        sp = login()
        tk.Frame.__init__(self, parent)
        self.controller = controller
        label = tk.Label(
            self, text="ID playlist canzoni piaciute", font="Times 15")
        label.pack(side="top", fill="x", pady=10)

        self.entry1 = tk.Entry(self, width=30)
        self.entry1.pack(side="top", fill="x", pady=10)

        label = tk.Label(
            self, text="ID playlist canzoni non piaciute", font="Times 15")
        label.pack(side="top", fill="x", pady=10)

        self.entry2 = tk.Entry(self, width=30)
        self.entry2.pack(side="top", fill="x", pady=10)

        def parametri():
            estrazioneCanzoni(sp, self.entry1.get(), self.entry2.get())
            controller.update_globals()
            controller.show_frame("PageOne")

        button1 = tk.Button(self, text="Analizza", command=lambda: parametri())

        button1.pack()


class PageOne(tk.Frame):

    def __init__(self, parent, controller):

        tk.Frame.__init__(self, parent)
        self.controller = controller

        label = tk.Label(self, text="Accuratezza", font=controller.title_font)
        label.pack(side="top", fill="x", pady=10)
        self.label1 = tk.Label(self, font="Times 12")
        self.label1.pack(side="top", fill="x", pady=10)
        self.label2 = tk.Label(self, font="Times 12")
        self.label2.pack(side="top", fill="x", pady=10)
        self.label3 = tk.Label(self, font="Times 12")
        self.label3.pack(side="top", fill="x", pady=10)
        self.label4 = tk.Label(self, font="Times 12")
        self.label4.pack(side="top", fill="x", pady=10)

    def update_globals(self):
        self.label1.config(text="Decision tree: {}".format(scoreDecisionTree))
        self.label2.config(text="Knn: {}".format(scoreKnn))
        self.label3.config(text="Random forest: {}".format(scoreRandomForest))
        self.label4.config(text="Kmeans: {}".format(scoreKmeans))

def login():
    # just a simple example to allow the program to run
    return 10


def estrazioneCanzoni(sp, a, b):
    # just a simple example to allow the program to run
    global scoreDecisionTree, scoreKnn, scoreRandomForest, scoreKmeans
    scoreDecisionTree, scoreKnn, scoreRandomForest, scoreKmeans = sp, a, b, a+b


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