在Python中打开XML文件并添加用户输入

Question

我正在使用python 2.7创建一个程序，使用Tkinter作为GUI和elementtree，其中用户输入的数据存储在XML文件中。 我设法使用python创建了XML文件，并将其保存到文件'crimeFile.xml'，其中包含所有空标记。 GUI还显示允许用户输入文本的字段和文本框。 问题是，当我尝试保存条目时，出现错误，并且数据没有保存到XML文件中。

from xml.etree import ElementTree
from xml.etree.ElementTree import Element
from xml.etree.ElementTree import SubElement
import xml.etree.ElementTree as ET
from Tkinter import *

class Application(Frame):

    def create_XML(self):
        crimeReport = Element('crime report')
        caseNo = SubElement(crimeReport, 'case number')

        victimDetails = SubElement(caseNo, 'victim details')
        victimFirstName = SubElement(victimDetails, 'victims first name')
        victimSecondName = SubElement(victimDetails, 'victim surname')
        victimAddress = SubElement(victimDetails, 'victim address')

        output_file = open('crimeFile.xml', 'w')
        output_file.write('<?xml version="1.0"?>')
        output_file.write(ElementTree.tostring(crimeReport))
        output_file.close()

    def save_XML(self):

        record = ET.SubElement(self.crimeReport, 'crime report')      
        caseNoNode = ET.SubElement(record, 'case number')
        caseNoNode.text = self.caseNo.get()
        victimFirstNameNode = ET.SubElement(record, 'first name')
        victimFirstNameNode.text = self.victimFirstName.get()
        victimSecondNameNode = ET.SubElement(record, 'surname')
        victimSecondNameNode.text = self.victimSecondName.get()
        victimAddressNode = ET.SubElement(record, 'address')
        victimAddressNode.text = self.victimAddress.get()

        self.tree.write('crimeReport.xml')
        self.clear_field()


    def create_Widgets(self):
        self.save = Button(self)
        self.save["text"] = "Save",
        self.save["command"] = self.save_XML
        self.save["bg"]   = "cyan"
        self.save.grid(row=0,column =2,sticky=W+E+N+S)

        self.crimeReportLabel = Label(self, text = 'Crime Report')
        self.crimeReportLabel.grid(row=1,column =1,sticky=W)

        self.caseNoLabel = Label(self,text="Case Number")
        self.caseNoLabel.grid(row=2,column =1,sticky=W)
        self.caseNo = Entry(self)
        self.caseNo.grid(row=2,column =2,sticky=W)

        self.victimDetailsLabel = Label(self,text="Victim Details")
        self.victimDetailsLabel.grid(row=3,column =1,sticky=W)

        self.victimFirstNameLabel = Label(self,text="First Name")
        self.victimFirstNameLabel.grid(row=4,column =1,sticky=W)
        self.victimFirstName = Entry(self)
        self.victimFirstName.grid(row=4,column =2,sticky=W)

        self.victimSecondNameLabel = Label(self,text="Surname")
        self.victimSecondNameLabel.grid(row=4,column =3,sticky=W)
        self.victimSecondName = Entry(self)
        self.victimSecondName.grid(row=4,column =4,sticky=W)

        self.victimAddressLabel = Label(self,text="Address")
        self.victimAddressLabel.grid(row=6,column =1,sticky=W)
        self.victimAddress = Entry(self)
        self.victimAddress.grid(row=6,column =2,sticky=W)

    def __init__(self, master = None):
        Frame.__init__(self, master)
        self.grid(column=5,row=25)
        self.create_Widgets()
        self.create_XML()


crimeReport = Tk()
app = Application(master = crimeReport)
app.mainloop()
crimeReport.destroy()

我得到的错误是：

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python27\lib\lib-tk\Tkinter.py", line 1532, in __call__
    return self.func(*args)
  File "C:\Users\Laleh\workspace\AdvDB20-02\program1\program1.py", line 60,  in save_XML
    record = ET.SubElement(self.crimeReport, 'crime report')
AttributeError: Application instance has no attribute 'crimeReport'

该程序的作用是创建一个XML文件供用户多次输入使用。 更新新条目并将其存储在此XML文件中（不覆盖以前的条目），以便以后可以搜索它并生成报告。 我是python的新手，不知道我要去哪里错了？

Answer 1

您的应用程序实例没有任何名为crimeReport属性

def save_XML(self):
    record = ET.SubElement(self.crimeReport, 'crime report')
                           ^

crimeReport仅在您的create_XML方法中定义。 您可以将crimeReport定义为类属性。

class Application(Frame):
    crimeReport = Element('crime report')

并在您的方法中使用self.crimeReport