Python使用Tkinter的贷款计算器详细介绍

Z时代
2024-01-10
分类：IT

先决条件：Tkinter介绍

Python提供了多种开发GUI(图形用户界面)的选项。在所有GUI方法中, tkinter是最常用的方法。它是Python随附的Tk GUI工具包的标准Python接口。带有tkinter的Python输出了创建GUI应用程序的最快, 最简单的方法。使用tkinter创建GUI很容易。

创建一个tkinter：

导入模块– tkinter

创建主窗口(容器)

将任意数量的小部件添加到主窗口

将事件触发器应用于小部件。

让我们看看如何使用Python GUI库Tkiner创建贷款计算器。该计算器将能够根据贷款金额, 期限和利率计算总金额和每月还款额。

第1步：创建一个主窗口。

def __init__( self ):
     # Create a window
     window = Tk() 
     window.title( "Loan Calculator" ) # Set title
     # create the input boxes.
     Label(window, text = "Annual Interest Rate" ).grid(row = 1 , column = 1 , sticky = W)
     Label(window, text = "Number of Years" ).grid(row = 2 , column = 1 , sticky = W)
     Label(window, text = "Loan Amount" ).grid(row = 3 , column = 1 , sticky = W)
     Label(window, text = "Monthly Payment" ).grid(row = 4 , column = 1 , sticky = W)
     Label(window, text = "Total Payment" ).grid(row = 5 , column = 1 , sticky = W)
     # for taking inputs
     self .annualInterestRateVar = StringVar()    
     Entry(window, textvariable = self .annualInterestRateVar, justify = RIGHT).grid(row = 1 , column = 2 )
     self .numberOfYearsVar = StringVar()
     Entry(window, textvariable = self .numberOfYearsVar, justify = RIGHT).grid(row = 2 , column = 2 )
     self .loanAmountVar = StringVar()
     Entry(window, textvariable = self .loanAmountVar, justify = RIGHT).grid(row = 3 , column = 2 )
     self .monthlyPaymentVar = StringVar()
     lblMonthlyPayment = Label(window, textvariable = 
                 self .monthlyPaymentVar).grid(row = 4 , column = 2 , sticky = E)
     self .totalPaymentVar = StringVar()
     lblTotalPayment = Label(window, textvariable =
                 self .totalPaymentVar).grid(row = 5 , column = 2 , sticky = E)
     # create the button
     btComputePayment = Button(window, text = "Compute Payment" , command = self .computePayment).grid(
                                row = 6 , column = 2 , sticky = E) 
     # Create an event loop     window.mainloop()

第2步：

添加功能。

def computePayment( self ):
     # compute the total payment.
     monthlyPayment = self .getMonthlyPayment( float ( self .loanAmountVar.get()), float ( self .annualInterestRateVar.get()) /1200 , int ( self .numberOfYearsVar.get()))
     self .monthlyPaymentVar. set ( format (monthlyPayment, '10.2f' ))
     totalPayment = float ( self .monthlyPaymentVar.get()) * 12 \
                            * int ( self .numberOfYearsVar.get())
     self .totalPaymentVar. set ( format (totalPayment, '10.2f' ))
# compute the monthly payment.
def getMonthlyPayment( self , loanAmount, monthlyInterestRate, numberOfYears): 
     monthlyPayment = loanAmount * monthlyInterestRate /
                     ( 1 - 1 /( 1 + monthlyInterestRate) * *
                     (numberOfYears * 12 ))
     return monthlyPayment;

步骤3：

完成程序

# Import tkinter
from tkinter import *
class LoanCalculator:
     def __init__( self ):
         window = Tk() # Create a window
         window.title( "Loan Calculator" ) # Set title
         # create the input boxes.
         Label(window, text = "Annual Interest Rate" ).grid(row = 1 , column = 1 , sticky = W)
         Label(window, text = "Number of Years" ).grid(row = 2 , column = 1 , sticky = W)
         Label(window, text = "Loan Amount" ).grid(row = 3 , column = 1 , sticky = W)
         Label(window, text = "Monthly Payment" ).grid(row = 4 , column = 1 , sticky = W)
         Label(window, text = "Total Payment" ).grid(row = 5 , column = 1 , sticky = W)
         # for taking inputs
         self .annualInterestRateVar = StringVar() 
         Entry(window, textvariable = self .annualInterestRateVar, justify = RIGHT).grid(row = 1 , column = 2 )
         self .numberOfYearsVar = StringVar()
         Entry(window, textvariable = self .numberOfYearsVar, justify = RIGHT).grid(row = 2 , column = 2 )
         self .loanAmountVar = StringVar()
         Entry(window, textvariable = self .loanAmountVar, justify = RIGHT).grid(row = 3 , column = 2 )
         self .monthlyPaymentVar = StringVar()
         lblMonthlyPayment = Label(window, textvariable = 
                            self .monthlyPaymentVar).grid(row = 4 , column = 2 , sticky = E)
         self .totalPaymentVar = StringVar()
         lblTotalPayment = Label(window, textvariable = 
                        self .totalPaymentVar).grid(row = 5 , column = 2 , sticky = E)
         # create the button
         btComputePayment = Button(window, text = "Compute Payment" , command = self .computePayment).grid(
                                   row = 6 , column = 2 , sticky = E) 
         window.mainloop() # Create an event loop
     # compute the total payment.
     def computePayment( self ):
         monthlyPayment = self .getMonthlyPayment(
         float ( self .loanAmountVar.get()), float ( self .annualInterestRateVar.get()) /1200 , int ( self .numberOfYearsVar.get()))
         self .monthlyPaymentVar. set ( format (monthlyPayment, '10.2f' ))
         totalPayment = float ( self .monthlyPaymentVar.get()) * 12 \
                                 * int ( self .numberOfYearsVar.get())
         self .totalPaymentVar. set ( format (totalPayment, '10.2f' ))
     def getMonthlyPayment( self , loanAmount, monthlyInterestRate, numberOfYears): 
         # compute the monthly payment.
         monthlyPayment = loanAmount * monthlyInterestRate /( 1
         - 1 /( 1 + monthlyInterestRate) * * (numberOfYears * 12 ))
         return monthlyPayment;
         root = Tk() # create the widget
  # call the class to run the program.LoanCalculator()