Tkinter登录窗口未居中求助：窗口偏移至屏幕左上角

我一眼就看出问题出在哪了——你在调用window.state("zoomed")之后立刻获取窗口的高度和宽度，但这时候窗口其实还没完成最大化的布局动作，拿到的h和w还是窗口初始状态的小尺寸，不是最大化后的真实尺寸。这样算出来的Center_h和Center_w完全不对，导致登录Frame被放在了实际最大化窗口的右上角区域，看起来就像是跑到左上角且内容超出可视范围了。

下面给你几个可行的解决办法：

方法一：延迟获取窗口尺寸 #

用after()方法等几百毫秒，让窗口完成最大化后再计算中心位置：

from tkinter import *
import sqlite3
import LoginMenu

class LogOn:
    def __init__(self, window):
        self.window = window
        window.title("Log On")
        window.state("zoomed")
        
        # 延迟执行布局逻辑，给窗口时间完成最大化
        self.window.after(200, self.setup_frame)
        
    def setup_frame(self):
        h = self.window.winfo_height()
        w = self.window.winfo_width()
        Center_h = h/2
        Center_w = w/2
        self.FrameLogOn = Frame(self.window, bg = "PaleTurquoise1")
        self.FrameLogOn.place(x = Center_w , y = Center_h, anchor = "center")
        
        # 以下控件创建代码保持不变
        self.lbl_TrainerID = Label(self.FrameLogOn, text = "TrainerID:", bg = "PaleTurquoise1", font =("Arial","16"), width = 15)
        self.lbl_TrainerID.grid(row = 0, column = 0)
        self.ent_TrainerID = Entry(self.FrameLogOn, bg = "PaleTurquoise1", font =("Arial","16"))
        self.ent_TrainerID.grid(row = 0, column = 1)
        self.lbl_TrainerIDError = Label(self.FrameLogOn, text = "*TrainerID Not Found" ,bg = "PaleTurquoise1", font =("Arial","16"), fg = "PaleTurquoise1", width = 15)
        self.lbl_TrainerIDError.grid(row = 0, column = 2)
        self.lbl_Password = Label(self.FrameLogOn, text = "Password:" ,bg = "PaleTurquoise1", font =("Arial","16"), width = 15)
        self.lbl_Password.grid(row = 1, column = 0)
        self.ent_Password = Entry(self.FrameLogOn, bg = "PaleTurquoise1", font =("Arial","16"))
        self.ent_Password.grid(row = 1, column = 1)
        self.lbl_PasswordError = Label(self.FrameLogOn, text = "*Incorrect Password" ,bg = "PaleTurquoise1", font =("Arial","16"), fg = "PaleTurquoise1", width = 15)
        self.lbl_PasswordError.grid(row = 1, column = 2)
        self.btn_LogIn = Button(self.FrameLogOn, text = "Log In", bg = "PaleTurquoise1", font =("Arial", "16"), width = 15, command = self.LogIn)
        self.btn_LogIn.grid(row = 2, column = 0, columnspan = 3)
        
    def LogIn(self):
        # 保留你的登录逻辑
        pass

if __name__ == "__main__":
    root = Tk()
    app = LogOn(root)
    root.mainloop()

方法二：用布局管理器自动居中（更推荐） #

其实不用手动计算位置，直接用pack让Frame自动居中，这样不管窗口怎么缩放，Frame都会保持在中心位置：

from tkinter import *
import sqlite3
import LoginMenu

class LogOn:
    def __init__(self, window):
        self.window = window
        window.title("Log On")
        window.state("zoomed")
        
        # 用pack让Frame自动居中，添加padding避免贴紧窗口边缘
        self.FrameLogOn = Frame(window, bg = "PaleTurquoise1")
        self.FrameLogOn.pack(expand=True, padx=20, pady=20)
        
        # 以下控件创建代码保持不变
        self.lbl_TrainerID = Label(self.FrameLogOn, text = "TrainerID:", bg = "PaleTurquoise1", font =("Arial","16"), width = 15)
        self.lbl_TrainerID.grid(row = 0, column = 0)
        self.ent_TrainerID = Entry(self.FrameLogOn, bg = "PaleTurquoise1", font =("Arial","16"))
        self.ent_TrainerID.grid(row = 0, column = 1)
        self.lbl_TrainerIDError = Label(self.FrameLogOn, text = "*TrainerID Not Found" ,bg = "PaleTurquoise1", font =("Arial","16"), fg = "PaleTurquoise1", width = 15)
        self.lbl_TrainerIDError.grid(row = 0, column = 2)
        self.lbl_Password = Label(self.FrameLogOn, text = "Password:" ,bg = "PaleTurquoise1", font =("Arial","16"), width = 15)
        self.lbl_Password.grid(row = 1, column = 0)
        self.ent_Password = Entry(self.FrameLogOn, bg = "PaleTurquoise1", font =("Arial","16"))
        self.ent_Password.grid(row = 1, column = 1)
        self.lbl_PasswordError = Label(self.FrameLogOn, text = "*Incorrect Password" ,bg = "PaleTurquoise1", font =("Arial","16"), fg = "PaleTurquoise1", width = 15)
        self.lbl_PasswordError.grid(row = 1, column = 2)
        self.btn_LogIn = Button(self.FrameLogOn, text = "Log In", bg = "PaleTurquoise1", font =("Arial", "16"), width = 15, command = self.LogIn)
        self.btn_LogIn.grid(row = 2, column = 0, columnspan = 3)
        
    def LogIn(self):
        # 保留你的登录逻辑
        pass

if __name__ == "__main__":
    root = Tk()
    app = LogOn(root)
    root.mainloop()

方法二更值得推荐，Tkinter的布局管理器本身就是用来解决这类位置适配问题的，比手动计算位置更稳定，窗口缩放时也能自动调整布局。

内容的提问来源于stack exchange，提问作者evansciaran