如何访问Kivy TextInput＆＃39; text＆＃39;来自.py文件的属性

Question

我在.py文件中创建了一个TextInput小部件，我正在尝试访问TextInput的值，因此我可以将它用于Sqlite3查询。出于某种原因，我不断收到错误说＆＃34; AttributeError：＆＃39; NoneType＆＃39;对象没有属性＆＃39; text＆＃39;＆＃34;。

如果我在.kv文件中创建窗口小部件并使用id作为ObjectProperty（），我可以访问TextInput_text值。我不确定我是否必须在.py文件中执行类似的操作。

这是我正在尝试的代码：

def choose_date_water(self):
    box = FloatLayout()
    box.add_widget(Label(text = "Select Date To View", font_size = (30), pos_hint = {'center_x':0.5, 'center_y': 0.9 }))


    self.dp1 = box.add_widget(TextInput(pHint_x = (0.35), pHint_y = (0.55), size_hint = (None, None), size = (190, 50), font_size = (33), pos_hint = {'center_x':0.5, 'center_y': 0.6 }))

    btn1 = Button(text = "OK", size_hint = (None, None), size = (200, 50), pos_hint = {'center_x':0.5, 'center_y': 0.25 })

    box.add_widget(btn1)

    popup1 = Popup(title = "Choose Date", title_size = (40), title_align = 'center', content = box, size_hint = (None, None), size = (600, 300))

    btn1.bind(on_press = self.view_water_figures, on_release = popup1.dismiss)

    popup1.open()
    return self.dp1





def view_water_figures(self, instance):
    conn = sqlite3.connect('logsheet.db')
    c = conn.cursor()

    c.execute("SELECT today_total_dw_vol, today_total_fw_vol, total_evap_out FROM waterfigures WHERE date = ?", (self.dp1.text,))

    wf = c.fetchall()

    print wf

任何帮助都会很棒。

感谢。

Answer 1

AttributeError - 说明

     c.execute("SELECT today_total_dw_vol, today_total_fw_vol, total_evap_out FROM waterfigures WHERE date = ?", (self.dp1.text,))
 AttributeError: 'NoneType' object has no attribute 'text'

self.dp1是一个ObjectProperty。 print(type(self.dp1))会显示它是<class 'NoneType'>的类型。它没有与TextInput小部件挂钩。解决方案如下：

片段

def choose_date_water(self):
    ...
    self.dp1 = TextInput(pHint_x = (0.35), pHint_y = (0.55), size_hint = (None, None), size = (190, 50), font_size = (33), pos_hint = {'center_x':0.5, 'center_y': 0.6 })

    box.add_widget(self.dp1)

解决方案 - 使用Python和Kv文件

1. 在kv文件中，为TextInput小部件指定一个ID，例如id: sel_date

2. 在Python代码中，使用self.ids look对象来访问kv文件中定义的TextInput文本。

   self.ids.sel_date.text

Accessing Widgets defined inside Kv lang in your python code

  

解析你的kv文件后，kivy会收集所有标记的小部件   id并将它们放在此self.ids字典类型属性

中

详情请参阅以下示例。

实施例

main.py

import sqlite3

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.config import Config


class SQLite3KivyDemo(BoxLayout):

    def db_query(self):
        connection = sqlite3.connect("company.db")

        cursor = connection.cursor()

        sql_command = """SELECT * FROM employee WHERE birth_date = "{}";""".format(self.ids.sel_date.text)
        cursor.execute(sql_command)

        result = cursor.fetchall()

        for row in result:
            print(row)


class TestApp(App):

    def build(self):
        Config.set("graphics", "width", "800")
        Config.set("graphics", "height", "50")
        Config.set("graphics", "borderless", "0")
        Config.set("graphics", "resizable", "0")
        self.title = "Kivy & SQLite3 Demo"
        return SQLite3KivyDemo()


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

test.kv

#:kivy 1.10.0

<SQLite3KivyDemo>:
    canvas.before:
        Color:
            rgb: 1, 0.5, 0  # Orange
            # rgb: 0, 0.5, 1  # Sky blue
        Rectangle:
            pos: self.pos
            size: self.size
    orientation: "vertical"
    BoxLayout:
        size_hint_y: 0.1
        Label:
            text: "Enter Date of Birth"
        TextInput:
            id: sel_date
            multiline: False
            size_hint_x: 3
        Button:
            text: "Display Data"
            on_release: root.db_query()

输出