Question

我是python，kivy和sqlite的新手。但我必须完成这项艰巨的任务。 :-(任何形式的帮助都将受到高度赞赏。提前致谢！

任务是：在android上的.db屏幕上显示kivy文件中的数据。

我从http://zetcode.com/db/sqlitepythontutorial/

创建了数据库文件

我在这里再次发布代码。

#!/usr/bin/python
# -*- coding: utf-8 -*-

import sqlite3 as lite
import sys

con = lite.connect('test.db')

with con:

    cur = con.cursor()    
    cur.execute("CREATE TABLE Cars(Id INT, Name TEXT, Price INT)")
    cur.execute("INSERT INTO Cars VALUES(1,'Audi',52642)")
    cur.execute("INSERT INTO Cars VALUES(2,'Mercedes',57127)")
    cur.execute("INSERT INTO Cars VALUES(3,'Skoda',9000)")
    cur.execute("INSERT INTO Cars VALUES(4,'Volvo',29000)")
    cur.execute("INSERT INTO Cars VALUES(5,'Bentley',350000)")
    cur.execute("INSERT INTO Cars VALUES(6,'Citroen',21000)")
    cur.execute("INSERT INTO Cars VALUES(7,'Hummer',41400)")
    cur.execute("INSERT INTO Cars VALUES(8,'Volkswagen',21600)")

然后将数据库保存到C:\\test.db。

然后我使用kivy和label制作了button屏幕。

# -*- coding: utf-8 -*-

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.lang import Builder

import random

root_widget = Builder.load_string('''
BoxLayout:
    orientation: 'vertical'
    Label:
        text: 'Hello'  #How to define it?
        font_size: 30
    Button:
        size: root.width/2, 15
        text: 'next random'
        font_size: 30
#        on_release:  #How to define it?
''')

class TestApp(App):
    def build(self):
        return root_widget

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

每次点击random时，我希望db file上显示label的{{1}} 车名。

最初的button文本，现在是“Hello”，应该用随机的汽车名称替换。因此，每次运行程序时，label上都会显示一个汽车名称。

但我真的不知道如何编写代码。

感谢您的帮助。

#UPDATE

我编写了代码，但它不起作用。

label

＃2更新：

现在代码是......它显示错误消息：# -*- coding: utf-8 -*- from kivy.app import App from kivy.uix.boxlayout import BoxLayout from kivy.uix.label import Label from kivy.lang import Builder from kivy.clock import mainthread import sqlite3 import random class MyBoxLayout(BoxLayout): def init(self, **kwargs): super().__init__(**kwargs) @mainthread # execute within next frame def delayed(): self.load_random_car() delayed() def load_random_car(self): conn = sqlite3.connect("C:\\test.db") cur = conn.cursor() ####Length of db file with conn: cur = conn.cursor() cur.execute("SELECT * FROM Cars") rows = cur.fetchall() LengthSQLFile = len(rows) print LengthSQLFile CurrentNo = random.randint(0, LengthSQLFile) CurrentNo_ForSearch = (CurrentNo ,) cur.execute("select * from Cars where rowid = ?" , CurrentNo_ForSearch) CurrentAll = cur.fetchone() CurrentAll = list(CurrentAll) # Change it from tuple to list print CurrentAll Current = CurrentAll[1] self.ids.label.text = Current #"fetch random car data from db and put here" root_widget = Builder.load_string(''' BoxLayout: orientation: 'vertical' Label: id: label font_size: 30 Button: size: root.width/2, 15 text: 'next random' font_size: 30 on_release: root.load_random_car() ''') class TestApp(App): def build(self): # MyBoxLayout(BoxLayout) return root_widget if __name__ == '__main__': TestApp().run()

AttributeError: 'BoxLayout' object has no attribute 'load_random_car'

Answer 1

最简单的方法是为框布局编写自定义init方法：

from kivy.uix.boxlayout import BoxLayout
from kivy.clock import mainthread

class MyBoxLayout(BoxLayout):

    def init(self, **kwargs):
        super().__init__(**kwargs)

        @mainthread  # execute within next frame
        def delayed():
            self.load_random_car()
        delayed()

    def load_random_car(self):
        self.ids.label.text = "fetch random car data from db and put here"

这是更新的小部件结构的样子：

MyBoxLayout:
    Label:
        id: label
    Button:
        on_release:  root.load_random_car()

Python + kivy + SQLite：如何一起使用它们

1 个答案: