如何从.py文件访问Kivy TextInput'文本'属性

问题描述

我已经在我的.py文件中创建了TextInput小部件，并且尝试访问TextInput的值，以便可以将其用于Sqlite3查询.由于某种原因，我一直收到错误消息，提示"AttributeError:'NoneType'对象没有属性'text'".

I have created a TextInput widget in my .py file and i am trying to access the value of the TextInput so i can use it for an Sqlite3 query. For some reason i keep getting an error saying "AttributeError: 'NoneType' object has no attribute 'text'".

如果我在.kv文件中创建窗口小部件并将ID用作ObjectProperty()，则能够访问TextInput_text值.我不确定是否必须在.py文件中执行类似的操作.

I am able to access TextInput_text values if i create the widget in the .kv file and use the id as an ObjectProperty(). I am unsure if i have to do something like that inside the .py file.

这是我正在尝试的代码:

Here is the code i am trying:

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.

谢谢.

推荐答案

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))将显示它是<class 'NoneType'>的类型.它没有连接到TextInput小部件.解决方法如下:

self.dp1 is an ObjectProperty. A print(type(self.dp1)) will show that it is a type of <class 'NoneType'>. It is not hook up to TextInput widget. The solution is as follow:

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小部件提供一个ID，例如id: sel_date

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

1. In kv file, give an id to the TextInput widget e.g. id: sel_date

2. In Python code, use self.ids look object to access the TextInput's text defined in kv file.

self.ids.sel_date.text

self.ids.sel_date.text

在您的python代码中访问在Kv lang内部定义的小部件

有关详细信息，请参见以下示例.

Please refer to the example below for details.

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

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