“NoneType”对象没有“generate_ticket”属性

Question

我不知道我为什么会犯这个错误。我是相当新的基维和错误可能是显而易见的那些更多的经验，所以请把你的知识传授给我。我假设我没有在kv语言中正确地使用函数调用，或者我没有在正确的地方定义函数。如果是这样的话，谁能给我一些建议，如何正确地做这件事。在

顺便说一句，我知道有些库目前还没有针对android的python方法，我稍后再讨论。我还知道，一旦我准备好移植到我的设备上，我将不得不为matplotlib/使用其他方法绘制图形。在

这是我的代码主.py公司名称：

from kivy.app import App
from kivy.uix.scatter import Scatter
from kivy.uix.label import Label
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.textinput import TextInput
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.gridlayout import GridLayout
from kivy.uix.relativelayout import RelativeLayout
from kivy.core.window import Window
from kivy.uix.image import Image
from kivy.graphics import BorderImage
from kivy.graphics import Color, Rectangle, Line


import random
import matplotlib.pyplot as plt
import pandas as pd
#import pylab as pl
import requests
import openpyxl as xl
#from operator import itemgetter
from collections import Counter
from lxml import html
import numpy as np

class HomeScreen(Screen):
    pass

class LotterySelcetionScreen(Screen):
    pass

class TableScreen(Screen):
    pass

class TutorialApp(App):

    screen_manager = None

    def build(self):
        #Window.clearcolor = (1,1,1,1)
        self.screen_manager = ScreenManager()
        self.screen_manager.add_widget(HomeScreen(name='home'))
        self.screen_manager.add_widget(LotterySelcetionScreen(name='lottery_selection'))
        self.screen_manager.add_widget(TableScreen(name='table'))

        #function to load the table form the excel file corresponding to the passed sheet name
        def loadTable(self, sheetName):
            lotteryData = pd.ExcelFile("Lottery databases.xlsx") #grabs and loads the file into memory
            df = lotteryData.parse(sheetName) #loads the data table form the corresponding sheetName into the df data frame
            return df

        #function to display the table
        def showTable(self, table):
            #get the number of rows the table has
            no_of_rows = len(table.index)
            #display the table

            return table.head(no_of_rows)

        #function to display pie charts of a specific column within the database
        #table is the database that the function will be working with
        #and column is a numberical vaule of which column to get the data from
        def printPieChart(self, table, column):
            if column == 6:
                columnList = table.iloc[:, -1:].values.T.ravel()
            else:
                columnList = table.iloc[:, (column - 7): (column - 6)].values.T.ravel()
            countedList = Counter(columnList)

            #set up the size of the pie chart
            fig = plt.figure(figsize=[10, 10])
            ax = fig.add_subplot(111)
            cmap = plt.prism()

            #input variables for pie function
            slices = [float(v) for v in countedList.values()]
            colors = cmap(np.linspace(0., 1., len(slices)))
            labels = [float(k) for k in countedList]
            columnHeaders = list(table.columns.values)

            #the pie chart
            pie_wedge_collection = ax.pie(slices, colors = colors, labels = labels, labeldistance = 1.05, autopct = '%1.1f%%')
            #get rid of the black outlines between the wedges and around the pie
            for pie_wedge in pie_wedge_collection[0]:
                pie_wedge.set_edgecolor('white')
            ax.set_title(columnHeaders[column + 1])
            #can't display a Legends as there's too many for plt.legends() too handle
            #return pyplot.pie([float(v) for v in countedList.values()], labels = [float(k) for k in countedList])

        def updateDatabase(self):
            wb = xl.load_workbook("Lottery databases.xlsx") #load the workbook into memory

            #list of the sheet names within the workbook
            sheetnames = ["SuperLotto", "MegaMillions", "Powerball"]
            days = ["Tue. ", "Wed. ", "Fri. ", "Sat. "] #days the draws on done on
            #list of the webpages to use grab the new draws
            webPages = ['http://www.calottery.com/play/draw-games/superlotto-plus/winning-numbers', 'http://www.calottery.com/play/draw-games/mega-millions/winning-numbers', 'http://www.calottery.com/play/draw-games/powerball/winning-numbers']
            x = 3
            while x != 0:
                ws = wb.get_sheet_by_name(sheetnames[x-1]) # which sheet to update
                rowIndex = ws.get_highest_row() # gets the highest row index in the sheet
                lastCellValue = ws.cell(row = rowIndex - 1, column = 0).value #gets the last value in the first column, draw number
                page = requests.get(webPages[x-1]) #grabs the webpage needed
                tree = html.fromstring(page.text) #puts the webpage into a tree structure to make it easy to traverse
                #get the newest draw and date from the webpage for comparasion purposes
                draw_and_date = tree.xpath('//*[@id="objBody_content_0_pagecontent_0_objPastWinningNumbers_rptPast_ctl01_lblDrawDateNumber"]/text()')
                #if the table is up to date, it will move on to the next table else it will update it 
                y = int(draw_and_date[0][-4:]) - int(lastCellValue) # checks to see how many draws are missing from the table
                if y == 0:
                    #print("The table for " + sheetnames[x-1] + " is up to date.")
                    x -= 1 #decrement x by 1 to move on to the next table
                else:
                    #while loop to check if the table needs to be updated or not, if yes it will update it
                    while y != 0:
                        #grabs the draw and date of the missing draws from the table
                        draw_and_date = tree.xpath('//*[@id="objBody_content_0_pagecontent_0_objPastWinningNumbers_rptPast_ctl0' + str(y) + '_lblDrawDateNumber"]/text()')
                        numbers = tree.xpath(".//*[@id='content']/div[3]/table/tr[" + str(y) + "]/td[2]/span/text()") #numbers
                        numbers = [int(x) for x in numbers] # converts the text to integers
                        numbers.sort() #sort the number from smallest to largest
                        mega = tree.xpath(".//*[@id='content']/div[3]/table/tr[" + str(y) + "]/td[3]/text()") #mega number
                        mega = int(mega[0]) # converts the text to integers
                        #write to the file
                        if sheetnames[x-1] == "MegaMillions":
                            d = 0
                        else:
                            d = 1
                        if int(draw_and_date[0][-4:]) % 2 == 0:
                            # if the draw date is even then the day is a Friday/Saturday
                            ws.append([int(draw_and_date[0][-4:]), (days[d+2] + draw_and_date[0][:12]), numbers[0], numbers[1], numbers[2], numbers[3], numbers[4], mega]) # print the draw date
                        else:
                            # if the draw date is odd then the day is a Tuesday/Wednesday
                            ws.append([int(draw_and_date[0][-4:]), (days[d] + draw_and_date[0][:12]), numbers[0], numbers[1], numbers[2], numbers[3], numbers[4], mega])
                        y -= 1 #decrement y by 1 to get the next missing draw
                    #print("Updated the " + sheetnames[x-1] + " table successfully!")
                    x -= 1 #decrement x by 1 to move on to the next table
            wb.save("Lottery databases.xlsx") #save the workbook
            #print("Saved the database Sucessfully!")

        # function to get a list of the occurring numbers in each column
        # 6 for the first number columns or 1 for the mega/powerball column
        def getPopularList(self, table, x):
            popular_list = list()
            if x != 1:
                while x != 0:
                    column_list = table.iloc[:, (0 - x): (1 - x)].values.T.ravel() # the all of the values in the column
                    counted_list = Counter(column_list) # counts how many time each value occurs within the column
                    top_five = counted_list.most_common(5) # the top five within the column
                    top_five.sort() # sorts the top five
                    popular_list = popular_list + top_five
                    x -= 1 # decrement x by 1
            else:
                column_list = table.iloc[:, (0 - x):].values.T.ravel() # the all of the values in the column
                counted_list = Counter(column_list) # counts how many time each value occurs within the column
                top_ten = counted_list.most_common(10) # the top five within the column
                top_ten.sort() # sorts the top five
                popular_list = popular_list + top_ten
            #popular_list is actually a tuple of list which contains the value and how many times that value occured
            #but we only want the values by themselves
            popular_list_values = [y[0] for y in popular_list] #this gives us a list of the values
            return popular_list_values

        # Function to generate a ticket based on the popular numbers in the lottery
        def generate_ticket(self, table):
            firstFive = self.getPopularList(table, 6) # get the popular numbers for the first five slots
            mega = self.getPopularList(table, 1) # gets the popular numbers for the mega/powerball slot
            five = self.getNumbers(firstFive, 5) # gets first five numbers for the ticket
            one = self.getNumbers(mega, 1) #gets the mega/powerball for the ticket
            five.append(one)
            return five

        #function to get numbers
        def getNumbers(self, numbers_list, x):
            numbers = list() #empty list
            rand_range_list = list(range(0, len(numbers_list))) #list of the numbers to choice from at random
            if x != 1:
                while x != 0:
                    y = random.choice(rand_range_list) #pick a number
                    #it's not making the list properly at the moment, FIX IT!
                    #numbers = numbers + numbers_list[y] #add a number to our list to return
                    numbers.append(numbers_list[y]) #append the number to the end of the list
                    rand_range_list.remove(y) #remove y from our rand_range_list to prevent any repeats
                    x -= 1
            else:
                numbers = random.choice(numbers_list) # add a number to our list to return
            return numbers

        # function to print the ticket based on which lottery it's from
        def printTicket(self, ticket, lottery):
            #small bubblesort for the first five numbers
            for x in range(1, 5):
                for y in range(0, 4):
                    if ticket[y] > ticket[y + 1]:
                        temp = ticket[y]
                        ticket[y] = ticket[y + 1]
                        ticket[y + 1] = temp
            #print statements depending on the lottery
            #print the ticket without any brackets
            if lottery != "Powerball":
                return str(ticket)[1:-4] + " Mega " + str(ticket[-1])
            else:
                return str(ticket)[1:-4] + " Powerball " + str(ticket[-1])

        return self.screen_manager 

if __name__ == '__main__':
    TutorialApp().run()

我的教程.kv公司名称：

^{pr2}$

回溯如下：

Traceback (most recent call last):
   File "/home/havik/workspace/kivyapp2.7/main.py", line 384, in <module>
     TutorialApp().run()
   File "/usr/lib/python2.7/dist-packages/kivy/app.py", line 798, in run
     root = self.build()
   File "/home/havik/workspace/kivyapp2.7/main.py", line 207, in build
     self.screen_manager.add_widget(TableScreen(name='table'))
   File "/usr/lib/python2.7/dist-packages/kivy/uix/relativelayout.py", line 255, in __init__
     super(RelativeLayout, self).__init__(**kw)
   File "/usr/lib/python2.7/dist-packages/kivy/uix/floatlayout.py", line 66, in __init__
     super(FloatLayout, self).__init__(**kwargs)
   File "/usr/lib/python2.7/dist-packages/kivy/uix/layout.py", line 66, in __init__
     super(Layout, self).__init__(**kwargs)
   File "/usr/lib/python2.7/dist-packages/kivy/uix/widget.py", line 271, in __init__
     Builder.apply(self)
   File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 1872, in apply
     self._apply_rule(widget, rule, rule)
   File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 2018, in _apply_rule
     e), cause=tb)
 kivy.lang.BuilderException: Parser: File "/home/havik/workspace/kivyapp2.7/tutorial.kv", line 45:
 ...
      43:       Label:
      44:           id: label1
 >>   45:           text: str(app.root.generate_ticket(app.root.loadTable('SuperLotto')))
      46:           height: 150
 ...
 BuilderException: Parser: File "/home/havik/workspace/kivyapp2.7/tutorial.kv", line 45:
 ...
      43:       Label:
      44:           id: label1
 >>   45:           text: str(app.root.generate_ticket(app.root.loadTable('SuperLotto')))
      46:           height: 150
 ...
 AttributeError: 'NoneType' object has no attribute 'generate_ticket'
   File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 1649, in create_handler
     return eval(value, idmap)
   File "/home/havik/workspace/kivyapp2.7/tutorial.kv", line 45, in <module>
     text: str(app.root.generate_ticket(app.root.loadTable('SuperLotto')))

   File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 2011, in _apply_rule
     value, rule, rctx['ids'])
   File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 1654, in create_handler
     cause=tb)

Answer 1

我试着按照crimement建议的方式来做，但是我无法在build方法中正确地定义屏幕，所以我尝试用kv语言修改代码，并能够解决这个问题。我真的很蠢，因为我没有早点意识到。我只需要去掉str的根(app.root.generate_票证(app.root.loadTable应用程序根目录（超级乐透）这就解决了问题。在

Answer 2

在设置app.root之前，在build方法中实例化一个表屏幕，因此app.root.generate_票证不存在。在

一种选择是直接在构建方法中设置表屏幕内容，而不是使用kv规则。在