刷新kivy小部件的问题
我在刷新BoxLayout小部件时遇到问题，方法是删除它们，然后根据列表“Groups”重建小部件。在EditDeviceGroups屏幕上，“创建”按钮应该向列表中添加一个元素，并将用户转发到GroupTemplateScreen，它就是这样。
当用户使用后退按钮返回EditDeviceGroups屏幕时，会出现此问题。那时，我认为on_enter方法会刷新小部件以包含新元素，但列表没有显示任何更改。
我认为这是类和实例的某种问题，但我不能完全看到这一点，因为这是我对Kivy的第一次真正尝试。
soundclout.py
from kivy.app import App
from kivy.properties import ObjectProperty, ListProperty, StringProperty
from kivy.uix.listview import ListItemButton
from kivy.uix.screenmanager import ScreenManager, Screen, WipeTransition
from kivy.uix.gridlayout import GridLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.scrollview import ScrollView
from kivy.uix.button import Button,Label
from kivy.graphics import Color,Rectangle,InstructionGroup
class GroupTemplateScreen(Screen):
def remove(self):
pass
class HomeScreen(Screen):
skipBuild = 'build_timeline_screen_6'
#skips build option if already timeline is already built
def skip_build_screen(self,value):
if value is 1:
print('HomeScreen.skip_build_screen')
self.skipBuild = 'edit_timeline_screen_7'
class EditDeviceGroupsScreen(Screen):
#Groups = [GroupNo,null]
Groups = [[1,10],[2,20]]
def on_enter(self):
self.ids.glayout2.clear_widgets()
for i in xrange(0,len(EditDeviceGroupsScreen().Groups)):
##THISPRINT##
print(str(EditDeviceGroupsScreen().Groups[i][0]))
addedGroup = BoxLayout(size_hint_y=None,height='120sp',orientation='horizontal')
addedButton=Button(text="Group " + str(EditDeviceGroupsScreen().Groups[i][0]) + " Settings",font_size=25)
addedGroup.add_widget(addedButton)
self.ids.glayout2.add_widget(addedGroup)
#Removes all widget on leaving to prevent the creation of duplicate widgets
def nav_to_group(self):
self.manager.current = 'edit_group_behaviour_screen_9'
def create_group(self):
base = 1
for i in xrange(0,len(EditDeviceGroupsScreen().Groups)):
if base < EditDeviceGroupsScreen().Groups[i][0]:
base = EditDeviceGroupsScreen().Groups[i][0]
EditDeviceGroupsScreen().Groups.append([base+1,(base+1)*10])
#manages screens
class Manager(ScreenManager):
home_screen = ObjectProperty()
edit_device_groups_screen = ObjectProperty()
group_template_screen= ObjectProperty()
def update(self):
self.connected_device_list._trigger_reset_populate()
self.current_screen.update()
class SoundCloutApp(App):
def build(self):
return Manager(transition=WipeTransition())
if __name__=='__main__':
SoundCloutApp().run()
soundclout.kv
#: kivy 1.10.0
#: import hex kivy.utils.get_color_from_hex
#: import main soundclout
#: import ListAdapter kivy.adapters.listadapter.ListAdapter
#: import ListItemButton kivy.uix.listview.ListItemButton
#: import ScrollView kivy.uix.scrollview
<GroupTemplateScreen>:
rows: 2
spacing: 10
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
size_hint_y: None
height: 50
spacing: 10
pos: root.x, (root.height-50)
# Make the background for the toolbar blue
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
on_press: root.manager.current = 'homescreen_1'
background_normal: 'icons/home.png'
size_hint_x: None
width:50
BoxLayout:
size_hint_y: None
height: 500
spacing: 50
padding: 20
pos: root.x, (root.height-560)
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
size_hint_y: None
orientation: "horizontal"
height: 50
spacing: 10
padding: 0
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
size_hint_x: None
size_hint_y: None
height: 50
width:100
text: 'Back'
on_release: root.manager.current = 'edit_device_groups_screen_5'
Button:
size_hint_x: None
size_hint_y: None
height: 50
width:100
text: 'Remove'
#have to change first arguement, for now assume switch is on
on_press: root.remove()
on_release:root.manager.current = 'edit_device_groups_screen_5'
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#ffffff')
Rectangle:
pos: self.pos
size: self.size
#Devices connected
BoxLayout:
orientation: "horizontal"
canvas:
Color:
rgba: hex('#98a6b3')
Rectangle:
pos: self.pos
size: self.size
Label:
text: 'Name:'
font_size: 24
#TODO
Label:
text: 'Group 1'
font_size: 24
#Devices connected
BoxLayout:
orientation: "horizontal"
canvas:
Color:
rgba: hex('#98a6b3')
Rectangle:
pos: self.pos
size: self.size
Label:
text: 'Devices:'
font_size: 24
#TODO
Label:
text: '1,2,3,4'
font_size: 24
<HomeScreen>:
rows: 2
spacing: 10
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
size_hint_y: None
height: 50
spacing: 10
pos: root.x, (root.height-50)
# Make the background for the toolbar blue
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
on_press: root.manager.current = 'homescreen_1'
background_normal: 'icons/home.png'
size_hint_x: None
width:50
BoxLayout:
size_hint_y: None
height: 500
spacing: 50
padding: 50
pos: root.x, (root.height-560)
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
text: "Start"
font_size: 20
Button:
text: "Device Tester"
font_size: 20
Button:
text: "Connect Devices"
font_size: 20
Button:
text: "Edit Device Groups"
font_size: 20
on_press: root.manager.current = 'edit_device_groups_screen_5'
Button:
text: "Edit Group Behavior"
font_size: 20
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Label:
text: "Connected Devices"
font_size: 30
<EditDeviceGroupsScreen>:
rows: 2
spacing: 10
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
#ToolBar
BoxLayout:
size_hint_y: None
height: 50
spacing: 10
pos: root.x, (root.height-50)
# Make the background for the toolbar blue
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
on_press: root.manager.current = 'homescreen_1'
background_normal: 'icons/home.png'
size_hint_x: None
width:50
BoxLayout:
size_hint_y: None
height: 500
spacing: 50
padding: 20
pos: root.x, (root.height-560)
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
size_hint_x: None
size_hint_y: None
height: 50
size: self.size
text: 'create group'
on_press: main.EditDeviceGroupsScreen().create_group()
on_release: root.manager.current = 'group_template_screen_11'
#Groups holder
BoxLayout:
orientation: "vertical"
spacing: 5
padding: 5
canvas:
Color:
rgba: hex('#ffffff')
Rectangle:
pos: self.pos
size: self.size
#Adds Scrollability
ScrollView:
do_scroll_x:False
do_scroll_Y:True
BoxLayout:
id: glayout2
orientation: 'vertical'
spacing: 5
size_hint_y: None
height: self.minimum_height
<Manager>:
id: screen_manager
home_screen: home_screen
edit_device_groups_screen: edit_device_groups_screen
group_template_screen: group_template_screen
HomeScreen:
id: home_screen
name: 'homescreen_1'
manager: screen_manager
EditDeviceGroupsScreen:
id: edit_device_groups_screen
name: 'edit_device_groups_screen_5'
manager: screen_manager
GroupTemplateScreen:
id: group_template_screen
name: 'group_template_screen_11'
manager: screen_manager
1 个答案:
答案 0 :(得分：0)
问题
EditDeviceGroups 屏幕不会使用新添加的小部件刷新，因为按 Back 按钮时，会实例化另一个 EditDeviceGroupScreen 实例。
解决方案
通过以下更改，当用户单击后退按钮返回到EditDeviceGroups屏幕时， on_enter 方法刷新窗口小部件以包含添加的新元素。有关详细信息，请参阅示例和输出。
soundclout.kv
- 已删除 ＃：import main soundclout
- 将 main.EditDeviceGroupsScreen（）。create_group（） 替换为 root.create_group（）
- 将所有 EditDeviceGroupsScreen（）。 替换为 self。
soundclout.py
实施例
main.py
from kivy.app import App
from kivy.properties import ObjectProperty, ListProperty, StringProperty
from kivy.uix.listview import ListItemButton
from kivy.uix.screenmanager import ScreenManager, Screen, WipeTransition
from kivy.uix.gridlayout import GridLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.scrollview import ScrollView
from kivy.uix.button import Button, Label
from kivy.graphics import Color, Rectangle, InstructionGroup
class GroupTemplateScreen(Screen):
def remove(self):
pass
class HomeScreen(Screen):
skipBuild = 'build_timeline_screen_6'
# skips build option if already timeline is already built
def skip_build_screen(self, value):
if value is 1:
print('HomeScreen.skip_build_screen')
self.skipBuild = 'edit_timeline_screen_7'
class EditDeviceGroupsScreen(Screen):
# Groups = [GroupNo, null]
Groups = [[1, 10], [2, 20]]
def on_enter(self):
print("EditDeviceGroupsScreen.on_enter:")
self.ids.glayout2.clear_widgets()
for i in range(0, len(self.Groups)):
##THISPRINT##
print(str(self.Groups[i][0]))
addedGroup = BoxLayout(size_hint_y=None, height='120sp', orientation='horizontal')
addedButton = Button(text="Group " + str(self.Groups[i][0]) + " Settings", font_size=25)
addedGroup.add_widget(addedButton)
self.ids.glayout2.add_widget(addedGroup)
# Removes all widget on leaving to prevent the creation of duplicate widgets
def nav_to_group(self):
self.manager.current = 'edit_group_behaviour_screen_9'
def create_group(self):
base = 1
for i in range(0, len(self.Groups)):
if base < self.Groups[i][0]:
base = self.Groups[i][0]
self.Groups.append([base+1, (base+1)*10])
# manages screens
class Manager(ScreenManager):
home_screen = ObjectProperty()
edit_device_groups_screen = ObjectProperty()
group_template_screen= ObjectProperty()
def update(self):
self.connected_device_list._trigger_reset_populate()
self.current_screen.update()
class SoundCloutApp(App):
def build(self):
return Manager(transition=WipeTransition())
if __name__ == '__main__':
SoundCloutApp().run()
soundclout.kv
#:kivy 1.10.0
#:import hex kivy.utils.get_color_from_hex
#:import ListAdapter kivy.adapters.listadapter.ListAdapter
#:import ListItemButton kivy.uix.listview.ListItemButton
#:import ScrollView kivy.uix.scrollview
<GroupTemplateScreen>:
rows: 2
spacing: 10
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
size_hint_y: None
height: 50
spacing: 10
pos: root.x, (root.height-50)
# Make the background for the toolbar blue
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
on_press: root.manager.current = 'homescreen_1'
background_normal: 'icons/home.png'
size_hint_x: None
width:50
BoxLayout:
size_hint_y: None
height: 500
spacing: 50
padding: 20
pos: root.x, (root.height-560)
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
size_hint_y: None
orientation: "horizontal"
height: 50
spacing: 10
padding: 0
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
size_hint_x: None
size_hint_y: None
height: 50
width:100
text: 'Back'
on_release: root.manager.current = 'edit_device_groups_screen_5'
Button:
size_hint_x: None
size_hint_y: None
height: 50
width:100
text: 'Remove'
#have to change first arguement, for now assume switch is on
on_press: root.remove()
on_release:root.manager.current = 'edit_device_groups_screen_5'
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#ffffff')
Rectangle:
pos: self.pos
size: self.size
#Devices connected
BoxLayout:
orientation: "horizontal"
canvas:
Color:
rgba: hex('#98a6b3')
Rectangle:
pos: self.pos
size: self.size
Label:
text: 'Name:'
font_size: 24
#TODO
Label:
text: 'Group 1'
font_size: 24
#Devices connected
BoxLayout:
orientation: "horizontal"
canvas:
Color:
rgba: hex('#98a6b3')
Rectangle:
pos: self.pos
size: self.size
Label:
text: 'Devices:'
font_size: 24
#TODO
Label:
text: '1,2,3,4'
font_size: 24
<HomeScreen>:
rows: 2
spacing: 10
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
size_hint_y: None
height: 50
spacing: 10
pos: root.x, (root.height-50)
# Make the background for the toolbar blue
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
on_press: root.manager.current = 'homescreen_1'
background_normal: 'icons/home.png'
size_hint_x: None
width:50
BoxLayout:
size_hint_y: None
height: 500
spacing: 50
padding: 50
pos: root.x, (root.height-560)
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
text: "Start"
font_size: 20
Button:
text: "Device Tester"
font_size: 20
Button:
text: "Connect Devices"
font_size: 20
Button:
text: "Edit Device Groups"
font_size: 20
on_press: root.manager.current = 'edit_device_groups_screen_5'
Button:
text: "Edit Group Behavior"
font_size: 20
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Label:
text: "Connected Devices"
font_size: 30
<EditDeviceGroupsScreen>:
rows: 2
spacing: 10
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
#ToolBar
BoxLayout:
size_hint_y: None
height: 50
spacing: 10
pos: root.x, (root.height-50)
# Make the background for the toolbar blue
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
on_press: root.manager.current = 'homescreen_1'
background_normal: 'icons/home.png'
size_hint_x: None
width:50
BoxLayout:
size_hint_y: None
height: 500
spacing: 50
padding: 20
pos: root.x, (root.height-560)
BoxLayout:
orientation: "vertical"
spacing: 10
padding: 10
canvas:
Color:
rgba: hex('#0099cc')
Rectangle:
pos: self.pos
size: self.size
Button:
size_hint_x: None
size_hint_y: None
height: 50
size: self.size
text: 'create group'
on_press: root.create_group()
on_release: root.manager.current = 'group_template_screen_11'
#Groups holder
BoxLayout:
orientation: "vertical"
spacing: 5
padding: 5
canvas:
Color:
rgba: hex('#ffffff')
Rectangle:
pos: self.pos
size: self.size
#Adds Scrollability
ScrollView:
do_scroll_x:False
do_scroll_Y:True
BoxLayout:
id: glayout2
orientation: 'vertical'
spacing: 5
size_hint_y: None
height: self.minimum_height
<Manager>:
id: screen_manager
home_screen: home_screen
edit_device_groups_screen: edit_device_groups_screen
group_template_screen: group_template_screen
HomeScreen:
id: home_screen
name: 'homescreen_1'
manager: screen_manager
EditDeviceGroupsScreen:
id: edit_device_groups_screen
name: 'edit_device_groups_screen_5'
manager: screen_manager
GroupTemplateScreen:
id: group_template_screen
name: 'group_template_screen_11'
manager: screen_manager
输出
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