代码之家 › 专栏 › 技术社区 › Håkon Hægland

之后未调用Entry validatecommandtkinter.messagebox.showwarning显示警告()已调用

tkinter python

Håkon Hægland · 技术社区 · 5 年前

Entry ,下面是一个最小的示例:

import tkinter as tk
from tkinter import messagebox

class MainWindow(tk.Tk):
    """ The main window
    """
    def __init__(self):
        tk.Tk.__init__(self)
        self.configure_window()


    def configure_window(self):
        """ Configure the main window
        """
        self.geometry("600x400")
        self.title("Testing entry validate command")
        self.bind_all('<Control-w>', lambda e: self.destroy())
        var1 = tk.StringVar(value="0")
        vcmd = (self.register(self.validate_input))
        entry1 = tk.Entry(
            self,
            textvariable=var1,
            validate='all',
            validatecommand=(vcmd, '%P'))
        entry1.place(relx=0.5, rely=0.5, anchor=tk.CENTER)

    def validate_input(self, txt):
        """ Validate that the input only contains digits
        """
        print(txt)
        if str.isdigit(txt) or txt == "":
            return True
        messagebox.showwarning(
            "Alert", "Please enter a positive integer")
        return False


def main():
    window = MainWindow()
    window.mainloop()

main()

validate_input() 在第一次显示警告消息后,不会调用方法。例如,如果用户在条目中输入“0”、“1”、“r”(三个按键), 验证输入() 为每个按键笔划调用,并为最后一个按键笔划(字母“r”)显示警告消息框。接下来,如果用户继续在条目中键入(在警告消息框中按“确定”之后),则 验证输入()

有什么问题吗?

3 回复 | 直到 5 年前

Delrius Euphoria TheLizzard 5 年前

自 this 问题没有正确答案,我无法将其作为副本关闭,但您只需要以下内容:

def validate_input(self, txt):
    """ Validate that the input only contains digits
    """
    print(txt)
    if txt.isdigit() or txt == "":
        return True
    else:
        messagebox.showwarning("Alert", "Please enter a positive integer")
        self.entry1.config(validate='all',validatecommand=(self.vcmd, '%P')) # Set the validation back
        return False

一定要说 self.entry1 self.vcmd :

self.vcmd = (self.register(self.validate_input))
self.entry1 = tk.Entry(self,textvariable=var1,validate='all',validatecommand=(self.vcmd, '%P'))
self.entry1.place(relx=0.5, rely=0.5, anchor=tk.CENTER)

虽然我不太清楚,为什么会这样,但这解决了它。看起来像是 messagebox 小部件丢失其 validation 我们还得再把它放回去。

validate='all' 到 validate='key'

self.entry1 = tk.Entry(self,textvariable=var1,validate='key',validatecommand=(self.vcmd, '%P'))

Bryan Oakley 5 年前

validate “全部”所有的“焦点”都在外。当对话框弹出时,条目失去焦点。这会导致tkinter在进行验证的过程中尝试进行另一轮验证。这可能会触发验证关闭,因为您可能会进入一个无法回避的循环。

TheLizzard 5 年前

不是最好的解决方案,但很有效:

import tkinter as tk
from tkinter import messagebox

class MainWindow(tk.Tk):
    """ The main window
    """
    def __init__(self):
        tk.Tk.__init__(self)
        self.configure_window()


    def configure_window(self):
        """ Configure the main window
        """
        self.geometry("600x400")
        self.title("Testing entry validate command")
        self.bind_all("<Control-w>", lambda e: self.destroy())
        vcmd = (self.register(self.validate_input))
        entry1 = tk.Entry(self)
        entry1.place(relx=0.5, rely=0.5, anchor=tk.CENTER)
        entry1.bind("<Key>", self.validate_input)

    def validate_input(self, event):
        """ Validate that the input only contains digits
        """
        if (event.state & 4) >> 2 == 1:
            # Ctrl+<event.keysym> was pressed
            if event.keysym == "c":
                # Ctrl+c pressed
                return None
            if event.keysym == "x":
                # Ctrl+x pressed
                return "break"
            if event.keysym == "v":
                # Ctrl+v pressed
                return "break"
        if not (event.char.isdigit() or event.char == ""):
            messagebox.showwarning(
                "Alert", "Please enter a positive integer")
            return "break"


def main():
    window = MainWindow()
    window.mainloop()

main()

"break" 从事件中,该事件被阻止且未被处理。