更新函数中的全局python变量

Question

我在类的方法中有一个函数，如下所示：

from tkinter import Frame, Tk, BOTH, Text, Menu, END
from tkinter import filedialog as tkFileDialog 

class Example(Frame):

    def __init__(self, parent):
        Frame.__init__(self, parent)   

        self.parent = parent        
        self.initUI()
        self.path = None
        print(self.path)
    def initUI(self):

        self.parent.title("File dialog")
        self.pack(fill=BOTH, expand=1)

        menubar = Menu(self.parent)
        self.parent.config(menu=menubar)

        fileMenu = Menu(menubar)
        fileMenu.add_command(label="Open_image", command=self.onOpen1)
        menubar.add_cascade(label="File", menu=fileMenu)        

    def onOpen1(self):

        ftypes = [('jpg files','.jpg'),('png files','.png'),('all files','.*')]
        dlg = tkFileDialog.Open(self, filetypes = ftypes)
        path = dlg.show()

        if path != '':
            self.path = path
            print(self.path)
            return self.path


def main():

    root = Tk()
    ex = Example(root)
    root.geometry("300x250+300+300")
    root.mainloop()  


if __name__ == '__main__':
    main() 

当我运行代码时自我路径函数中的变量发生变化。但是自我路径函数外部的全局变量不变。你知道吗

我想要自我路径在函数外部更新。事实上，我想更新自我路径带有onOpen1函数的变量。此功能打开一个窗口，允许您选择图像。然后，我要恢复此图像的路径以进行更新自我路径. 你知道吗

Answer 1

这个按钮只是一种帮助你想象正在发生的事情的方法。这是完整的代码。你知道吗

from tkinter import Frame, Tk, BOTH, Text, Menu, END, Button
from tkinter import filedialog as tkFileDialog 

class Example(Frame):

    def __init__(self, parent):
        Frame.__init__(self, parent)   

        self.parent = parent        
        self.initUI()
        self.path = None
        print(self.path)

    def initUI(self):
        self.parent.title("File dialog")
        self.pack(fill=BOTH, expand=1)

        menubar = Menu(self.parent)
        self.parent.config(menu=menubar)

        fileMenu = Menu(menubar)
        fileMenu.add_command(label="Open_image", command=self.onOpen1)
        menubar.add_cascade(label="File", menu=fileMenu) 

        button = Button(self.parent, text='test', command=self.test)  
        button.pack()     

    def test(self):
        print(self.path)

    def onOpen1(self):

        ftypes = [('jpg files','.jpg'),('png files','.png'),('all files','.*')]
        dlg = tkFileDialog.Open(self, filetypes = ftypes)
        path = dlg.show()

        if path != '':
            self.path = path
            print(self.path)
            return self.path


def main():

    root = Tk()
    ex = Example(root)
    root.geometry("300x250+300+300")
    root.mainloop()  


if __name__ == '__main__':
    main() 

运行它，并观察您的控制台打印将发生。 按下按钮。注意怎么做自我路径没有。你知道吗

现在，在“文件”对话框中选择一个图像。你知道吗

再按一下按钮。注意怎么做自我路径更改以反映图像的路径是什么？你知道吗

你说你想更新自我路径以反映您选择的内容。你的代码确实做到了。这种形象化的目的是向你展示，你所问的问题可能不是你所面临问题的解决方案。你知道吗

这是我认为你想要的一个例子。你知道吗

from tkinter import Frame, Tk, BOTH, Text, Menu, END, Button, Label
from tkinter import filedialog as tkFileDialog
import cv2
from PIL import ImageTk, Image

class Example(Frame):

    def __init__(self, parent):
        Frame.__init__(self, parent)   

        self.parent = parent        
        self.initUI()
        self.path = None
        print(self.path)

    def initUI(self):
        self.parent.title("File dialog")
        self.pack(fill=BOTH, expand=1)

        menubar = Menu(self.parent)
        self.parent.config(menu=menubar)

        fileMenu = Menu(menubar)
        fileMenu.add_command(label="Open_image", command=self.onOpen1)
        menubar.add_cascade(label="File", menu=fileMenu) 

    def test(self):
        print(self.path)

    def onOpen1(self):

        ftypes = [('jpg files','.jpg'),('png files','.png'),('all files','.*')]
        dlg = tkFileDialog.Open(self, filetypes = ftypes)
        path = dlg.show()

        if path != '':
            self.path = path
            self.add_image()

    def add_image(self):
        img = cv2.imread(self.path)
        img = cv2.resize(img,(224, 224), interpolation = cv2.INTER_AREA)
        image1 = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        image1 = Image.fromarray(image1)
        image1 = ImageTk.PhotoImage(image1)
        panelA = Label(self, image=image1)
        panelA.image = image1
        panelA.grid(row=0, column=0, sticky='w')

def main():

    root = Tk()
    ex = Example(root)
    root.geometry("300x250+300+300")
    root.mainloop()  


if __name__ == '__main__':
    main() 

下面是两帧的示例代码。你知道吗

from tkinter import Frame, Tk, BOTH, Text, Menu, END, Button, Label
from tkinter import filedialog as tkFileDialog
import cv2
from PIL import ImageTk, Image

class Example(Frame):

    def __init__(self, parent):
        Frame.__init__(self, parent)

        self.parent = parent
        self.initUI()
        self.current_window = 0
        self.path = None
        self.panelA = None
        self.panelB = None
        print(self.path)

    def initUI(self):
        self.parent.title("File dialog")
        #self.pack(fill=BOTH, expand=1)

        menubar = Menu(self.parent)
        self.parent.config(menu=menubar)

        fileMenu = Menu(menubar)
        fileMenu.add_command(label="Open Image 1", command=lambda: self.onOpen1(1))
        fileMenu.add_command(label="Open Image 2", command=lambda: self.onOpen1(2))
        menubar.add_cascade(label="File", menu=fileMenu)

        self.button_1 = Button(self.parent, text='Window 1', command=lambda: self.switch_window(1))
        self.button_2 = Button(self.parent, text='Window 2', command=lambda: self.switch_window(2))
        self.back_button = Button(self.parent, text='Back', command=lambda: self.switch_window(0))

        self.button_1.grid(sticky='w')
        self.button_2.grid(sticky='w')

    def switch_window(self, window):
        self.current_window = window
        if window == 0:
            self.back_button.grid_forget()
            self.button_1.grid(sticky='w')
            self.button_2.grid(sticky='w')
        else:
            self.button_1.grid_forget()
            self.button_2.grid_forget()
            self.back_button.grid(row=1, sticky='w')

        self.repopulate_windows()

    def onOpen1(self, image_selection):
        ftypes = [('jpg files','.jpg'),('png files','.png'),('all files','.*')]
        dlg = tkFileDialog.Open(self, filetypes = ftypes)
        path = dlg.show()

        if path != '':
            self.path = path
            self.add_image(image_selection)

    def add_image(self, image_selection):
        img = cv2.imread(self.path)
        img = cv2.resize(img,(224, 224), interpolation = cv2.INTER_AREA)
        image1 = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        image1 = Image.fromarray(image1)
        image1 = ImageTk.PhotoImage(image1)

        if image_selection == 1:
            self.panelA = Label(self.parent, image=image1)
            self.panelA.image = image1
        else:
            self.panelB = Label(self.parent, image=image1)
            self.panelB.image = image1

        if self.current_window != 0:
            self.repopulate_windows()

    def repopulate_windows(self):
        if self.current_window == 1:
            if self.panelB is not None:
                self.panelB.grid_forget()
            if self.panelA is not None:
                self.panelA.grid(row=0, column=0, sticky='w')
        elif self.current_window == 2:
            if self.panelA is not None:
                self.panelA.grid_forget()
            if self.panelB is not None:
                self.panelB.grid(row=0, column=0, sticky='w')
        else:
            if self.panelA is not None:
                self.panelA.grid_forget()
            if self.panelB is not None:
                self.panelB.grid_forget()

def main():

    root = Tk()
    ex = Example(root)
    root.geometry("300x250+300+300")
    root.mainloop()


if __name__ == '__main__':
    main()