Python，KivyMD从文本字段获取数据
由于几个星期以来，我一直在使用KivyMD，所以我爱上了这个Kivy主题。 这是我的问题：我正在使用KivyMD制作多屏应用程序，而我的第一个屏幕是“登录屏幕”。我想在主类中添加一个函数，该函数获取“用户名”文本字段和“密码”文本字段的值。如果标识符正确，则将我带到“ screen2”。
这是我的代码：
from kivy.app import App
from kivy.lang import Builder
from kivy.properties import ObjectProperty
from kivy.uix.boxlayout import BoxLayout
from kivymd.theming import ThemeManager
class MyLayout(BoxLayout):
scr_mngr = ObjectProperty(None)
def change_screen(self, screen, *args):
self.scr_mngr.current = screen
KV = """
#:import Toolbar kivymd.toolbar.Toolbar
#:import ThemeManager kivymd.theming.ThemeManager
#:import MDNavigationDrawer kivymd.navigationdrawer.MDNavigationDrawer
#:import NavigationLayout kivymd.navigationdrawer.NavigationLayout
#:import NavigationDrawerDivider
kivymd.navigationdrawer.NavigationDrawerDivider
#:import NavigationDrawerToolbar
kivymd.navigationdrawer.NavigationDrawerToolbar
#:import NavigationDrawerSubheader
kivymd.navigationdrawer.NavigationDrawerSubheader
#:import MDCheckbox kivymd.selectioncontrols.MDCheckbox
#:import MDSwitch kivymd.selectioncontrols.MDSwitch
#:import MDList kivymd.list.MDList
#:import OneLineListItem kivymd.list.OneLineListItem
#:import TwoLineListItem kivymd.list.TwoLineListItem
#:import ThreeLineListItem kivymd.list.ThreeLineListItem
#:import OneLineAvatarListItem kivymd.list.OneLineAvatarListItem
#:import OneLineIconListItem kivymd.list.OneLineIconListItem
#:import OneLineAvatarIconListItem kivymd.list.OneLineAvatarIconListItem
#:import MDTextField kivymd.textfields.MDTextField
#:import MDSpinner kivymd.spinner.MDSpinner
#:import MDCard kivymd.card.MDCard
#:import MDSeparator kivymd.card.MDSeparator
#:import MDDropdownMenu kivymd.menu.MDDropdownMenu
#:import get_color_from_hex kivy.utils.get_color_from_hex
#:import colors kivymd.color_definitions.colors
#:import SmartTile kivymd.grid.SmartTile
#:import MDSlider kivymd.slider.MDSlider
#:import MDTabbedPanel kivymd.tabs.MDTabbedPanel
#:import MDTab kivymd.tabs.MDTab
#:import MDProgressBar kivymd.progressbar.MDProgressBar
#:import MDAccordion kivymd.accordion.MDAccordion
#:import MDAccordionItem kivymd.accordion.MDAccordionItem
#:import MDAccordionSubItem kivymd.accordion.MDAccordionSubItem
#:import MDThemePicker kivymd.theme_picker.MDThemePicker
#:import MDBottomNavigation kivymd.tabs.MDBottomNavigation
#:import MDBottomNavigationItem kivymd.tabs.MDBottomNavigationItem
#:import partial functools.partial
MyLayout:
scr_mngr: scr_mngr
orientation: 'vertical'
ScreenManager:
id: scr_mngr
Screen:
name: 'screen1'
MDCard:
size_hint: None, None
size: dp(520), dp(340)
pos_hint: {'center_x': 0.5, 'center_y': 0.5}
BoxLayout:
orientation:'vertical'
padding: dp(20)
spacing:20
MDLabel:
text: 'Connexion'
theme_text_color: 'Secondary'
font_style:"Title"
size_hint_y: None
height: dp(36)
MDSeparator:
height: dp(1)
MDTextField:
id: 'username'
hint_text: "Username "
helper_text_mode: "on_focus"
MDTextField:
id: 'password'
hint_text: "Password "
helper_text_mode: "on_focus"
MDFlatButton:
text: "Connexion"
pos_hint: {'center_x': 0.5}
on_release: root.check_data_login()
Screen:
name: 'screen2'
Toolbar:
id: toolbar
title: "Welcome ! "
pos_hint: {'center_x': 0.5, 'center_y': 0.97}
md_bg_color: app.theme_cls.primary_color
background_palette: 'DeepPurple'
background_hue: 'A400'
left_action_items: [['arrow-left', p
partial(root.change_screen, 'screen1') ]]
right_action_items: [['animation', lambda x: M
MDThemePicker().open()]]
MDLabel:
font_style: 'Title'
theme_text_color: 'Primary'
text: "Data :"
height: self.texture_size[1] + dp(3)
halign: 'center'
pos_hint: {'center_x': 0.5, 'center_y': 0.85}
"""
class MyApp(App):
theme_cls = ThemeManager()
def build(self):
return Builder.load_string(KV)
def check_data_login(self):
username = self.username.text
password= self.password.text
print(username)
print(password)
MyApp().run()
2 个答案:
答案 0 :(得分：1)
解决方案
解决方案是使用Kivy ObjectProperty连接到ID。有关详细信息，请参阅示例。
kv文件
添加以下ID和对象属性
- 添加
id: screen1 - 添加ObjectProperty
screen1: screen1 - id不是字符串。删除
id: username和id: password中的引号 - 添加ObjectProperty
username: username - 添加ObjectProperty
password: password - 将
password: True添加到TextInput，以便屏蔽密码
摘要-kv文件
ScreenManager:
id: scr_mngr
screen1: screen1
Screen:
id: screen1
name: 'screen1'
username: username
password: password
MDCard:
...
MDTextField:
id: username
hint_text: "Username "
helper_text_mode: "on_focus"
MDTextField:
id: password
hint_text: "Password "
helper_text_mode: "on_focus"
password: True
Python文件
- 将
check_data_login()的方法从class MyApp()移到class MyLayout() - 将
self.username.text替换为self.scr_mngr.screen1.username.text - 将
self.password.text替换为self.scr_mngr.screen1.password.text - 添加了如果语句以检查用户名和密码
代码段-Python文件
class MyLayout(BoxLayout):
scr_mngr = ObjectProperty(None)
def check_data_login(self):
username = self.scr_mngr.screen1.username.text
password = self.scr_mngr.screen1.password.text
print(username)
print(password)
if username == "KivyMD" and password == "kivy":
self.change_screen("screen2")
Kivy文档
如果小部件没有具有给定名称的属性，则 ObjectProperty将自动创建并添加到小部件中。
警告
为ID分配值时，请记住该值不是字符串。 没有引号：好-> id：值，差-> id：“值”
Accessing Widgets defined inside Kv lang in your python code
通常认为使用ObjectProperty是“最佳实践”。 这将创建直接参考，提供更快的访问权限，并且还具有更多优势 明确的。
示例
main.py
from kivy.app import App
from kivy.lang import Builder
from kivy.properties import ObjectProperty
from kivy.uix.boxlayout import BoxLayout
from kivymd.theming import ThemeManager
class MyLayout(BoxLayout):
scr_mngr = ObjectProperty(None)
def check_data_login(self):
username = self.scr_mngr.screen1.username.text
password = self.scr_mngr.screen1.password.text
print(username)
print(password)
if username == "KivyMD" and password == "kivy":
self.change_screen("screen2")
def change_screen(self, screen, *args):
self.scr_mngr.current = screen
KV = """
#:import Toolbar kivymd.toolbar.Toolbar
#:import ThemeManager kivymd.theming.ThemeManager
#:import MDNavigationDrawer kivymd.navigationdrawer.MDNavigationDrawer
#:import NavigationLayout kivymd.navigationdrawer.NavigationLayout
#:import NavigationDrawerDivider kivymd.navigationdrawer.NavigationDrawerDivider
#:import NavigationDrawerToolbar kivymd.navigationdrawer.NavigationDrawerToolbar
#:import NavigationDrawerSubheader kivymd.navigationdrawer.NavigationDrawerSubheader
#:import MDCheckbox kivymd.selectioncontrols.MDCheckbox
#:import MDSwitch kivymd.selectioncontrols.MDSwitch
#:import MDList kivymd.list.MDList
#:import OneLineListItem kivymd.list.OneLineListItem
#:import TwoLineListItem kivymd.list.TwoLineListItem
#:import ThreeLineListItem kivymd.list.ThreeLineListItem
#:import OneLineAvatarListItem kivymd.list.OneLineAvatarListItem
#:import OneLineIconListItem kivymd.list.OneLineIconListItem
#:import OneLineAvatarIconListItem kivymd.list.OneLineAvatarIconListItem
#:import MDTextField kivymd.textfields.MDTextField
#:import MDSpinner kivymd.spinner.MDSpinner
#:import MDCard kivymd.card.MDCard
#:import MDSeparator kivymd.card.MDSeparator
#:import MDDropdownMenu kivymd.menu.MDDropdownMenu
#:import get_color_from_hex kivy.utils.get_color_from_hex
#:import colors kivymd.color_definitions.colors
#:import SmartTile kivymd.grid.SmartTile
#:import MDSlider kivymd.slider.MDSlider
#:import MDTabbedPanel kivymd.tabs.MDTabbedPanel
#:import MDTab kivymd.tabs.MDTab
#:import MDProgressBar kivymd.progressbar.MDProgressBar
#:import MDAccordion kivymd.accordion.MDAccordion
#:import MDAccordionItem kivymd.accordion.MDAccordionItem
#:import MDAccordionSubItem kivymd.accordion.MDAccordionSubItem
#:import MDThemePicker kivymd.theme_picker.MDThemePicker
#:import MDBottomNavigation kivymd.tabs.MDBottomNavigation
#:import MDBottomNavigationItem kivymd.tabs.MDBottomNavigationItem
#:import partial functools.partial
MyLayout:
scr_mngr: scr_mngr
orientation: 'vertical'
ScreenManager:
id: scr_mngr
screen1: screen1
Screen:
id: screen1
name: 'screen1'
username: username
password: password
MDCard:
size_hint: None, None
size: dp(520), dp(340)
pos_hint: {'center_x': 0.5, 'center_y': 0.5}
BoxLayout:
orientation:'vertical'
padding: dp(20)
spacing:20
MDLabel:
text: 'Connexion'
theme_text_color: 'Secondary'
font_style:"Title"
size_hint_y: None
height: dp(36)
MDSeparator:
height: dp(1)
MDTextField:
id: username
hint_text: "Username "
helper_text_mode: "on_focus"
MDTextField:
id: password
hint_text: "Password "
helper_text_mode: "on_focus"
password: True
MDFlatButton:
text: "Connexion"
pos_hint: {'center_x': 0.5}
on_release: root.check_data_login()
Screen:
name: 'screen2'
Toolbar:
id: toolbar
title: "Welcome ! "
pos_hint: {'center_x': 0.5, 'center_y': 0.97}
md_bg_color: app.theme_cls.primary_color
background_palette: 'DeepPurple'
background_hue: 'A400'
left_action_items: [['arrow-left', partial(root.change_screen, 'screen1') ]]
right_action_items: [['animation', lambda x: MDThemePicker().open()]]
MDLabel:
font_style: 'Title'
theme_text_color: 'Primary'
text: "Data :"
height: self.texture_size[1] + dp(3)
halign: 'center'
pos_hint: {'center_x': 0.5, 'center_y': 0.85}
"""
class MyApp(App):
title = "Kivy MD Demo"
theme_cls = ThemeManager()
def build(self):
return Builder.load_string(KV)
MyApp().run()
输出
答案 1 :(得分：0)
另一种带有按钮的方法。 您的kv文件：
KV = """
Screen:
MDLabel:
id: direct
text: 'Paste File Path: '
color: [0.6,0.5,0.3,1,1]
pos_hint: {"center_x": .55, "center_y": .7}
MDTextField:
id: getpath
hint_text: "Include file name with its extension"
pos_hint: {"center_x": .5, "center_y": 0.7}
size_hint_x: None
width: "300dp"
MDRaisedButton:
text: "Check Text"
color: "green"
pos_hint: {"center_x": .5, "center_y": .45}
on_release: app.checkprint()
"""
以及您的主要python脚本：
class OneApp(MDApp):
def build(self):
self.theme_cls.primary_palette = 'Green'
self.screen = Builder.load_string(KV)
return self.screen
def checkprint(self):
value = self.screen.ids.getpath.text
print("What you typed is: ", value)
OneApp().run()
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