Question

以下代码出现错误，其中＆＃34;添加任务＆＃34;按钮将通过在2个任务之间创建空格将空输入添加到列表框中。有没有办法在不可能发生的地方编码？我希望列表框中的列表是连续的，每个任务一个接一个地出现。我不明白为什么会这样。它是python的一部分吗？再次感谢。

import tkinter as tk


def main():

    root = tk.Tk()
    root.geometry("350x450")
    root.title("basic window")
    root.config(background="azure")
    app = Application (root)
    root.mainloop()


class Application(tk.Frame):

    def __init__(self, parent):
        tk.Frame.__init__(self, parent, bg="yellow", bd=2, relief=tk.RIDGE)   
        self.parent = parent
        self.initUI()


    def initUI(self):
        self.pack(fill="both", expand=1)

        #widget layout

        self.listbox = tk.Listbox(self, bd=2, relief=tk.SUNKEN, height="15")
        self.listbox.grid(row=0, column=0, sticky="w", padx=5, pady=5)

        self.entry=tk.Entry(self, width=19)
        self.entry.grid(row=1, stick="w", padx=5)

        self.button1=tk.Button(self, text="add task", command=self.update)
        self.button1.grid(row=1, column=1, sticky="w", padx=5)

        self.label=tk.Label(self, text="stats", bg="yellow")
        self.label.grid(row=0, column=1, sticky="n")

        #programing

    def update(self):

        self.listbox.insert("end", self.entry.get())
        self.entry.delete(0, "end")



if __name__ == '__main__':
    main()

Answer 1

在update(self)中

，您需要测试self.entry.get()是否包含空字符串;如果是，请跳过更新。

import tkinter as tk

class Application(tk.Frame):

    def __init__(self, parent):
        tk.Frame.__init__(self, parent, bg="yellow", bd=2, relief=tk.RIDGE)   
        self.parent = parent
        self.initUI()


    def initUI(self):
        self.pack(fill="both", expand=1)

        #widget layout

        self.listbox = tk.Listbox(self, bd=2, relief=tk.SUNKEN, height="15")
        self.listbox.grid(row=0, column=0, sticky="w", padx=5, pady=5)

        self.entry=tk.Entry(self, width=19)
        self.entry.grid(row=1, stick="w", padx=5)

        self.button1=tk.Button(self, text="add task", command=self.update)
        self.button1.grid(row=1, column=1, sticky="w", padx=5)

        self.label=tk.Label(self, text="stats", bg="yellow")
        self.label.grid(row=0, column=1, sticky="n")

        #programing

    def update(self):
        if self.entry.get() != '':
            self.listbox.insert("end", self.entry.get())
            self.entry.delete(0, "end")


def main():
    root = tk.Tk()
    root.geometry("350x450")
    root.title("basic window")
    root.config(background="azure")
    app = Application (root)
    root.mainloop()

if __name__ == '__main__':
    main()

Answer 2

def update(self):
        if not self.entry.get()== "": #.get gets the value thgat the entry contains
            self.listbox.insert("end", self.entry.get())
            self.entry.delete(0, "end")

另外在旁注中我建议使用更好的名称，例如代替self.entry使用self.intput_txt，当我制作对象时，我倾向于使用_txt或_lbl ectra因为它使一眼就能看出它是什么类型的物体

如何进行＆＃34;添加任务＆＃34;按钮不接受空字符串？

2 个答案: