我试图创建一个滚动视图，我通过下拉菜单选择一个选项，然后按+按钮将一行中的两个标签添加到滚动视图中。到目前为止，这是我的代码：
from kivy.app import App
from kivy.uix.label import Label
from kivy.lang import Builder
from kivy.properties import ListProperty
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.dropdown import DropDown
from kivy.uix.button import Button
from kivy.uix.textinput import TextInput
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
class CaloriesScreen(Screen):
pass
class theScreenManager(ScreenManager):
pass
root_widget = Builder.load_string('''
#:import FadeTransition kivy.uix.screenmanager.FadeTransition
theScreenManager:
CaloriesScreen:
<CaloriesScreen>:
name: 'calories'
BoxLayout:
orientation: 'vertical'
BoxLayout:
orientation: 'horizontal'
size_hint: 1, .3
Button:
text: '<'
size_hint: .1, 1
font_size: 75
background_normal: ""
background_color: 0.18, .5, .92, 1
on_release: app.root.current = 'main'
Label:
text: 'Calories'
halign: 'left'
font_size: 50
canvas.before:
Color:
rgb: 0.18, .5, .92
Rectangle:
pos: self.pos
size: self.size
Widget:
size_hint: .1, 1
canvas.before:
Color:
rgb: 0.18, .5, .92
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
orientation: 'horizontal'
size_hint: 1, .4
spacing: 50
canvas.before:
Color:
rgb: 0.8, 0.8, 0.8
Rectangle:
pos: self.pos
size: self.size
Label:
text: 'Recipes'
font_size: 30
color: 0.18, .5, .92, 1
Button:
id: btn
text: 'Select a recipe...'
font_size: 30
on_release: dropdown.open(self)
height: '48dp'
pos_hint: { 'top' : 0.75}
size_hint: .8, .5
DropDown:
id: dropdown
on_parent: self.dismiss()
on_select: btn.text = '{}'.format(args[1])
Button:
text: 'Simple Cheese Omelette'
size_hint_y: None
height: '48dp'
on_release: dropdown.select('First Item')
Button:
text: 'Burger'
size_hint_y: None
height: '48dp'
on_release: dropdown.select('Second Item')
Button:
text: 'Tomato and Caper Linguine'
size_hint_y: None
height: '48dp'
on_release: dropdown.select('Third Item')
Button:
text: '+'
font_size: 30
background_normal: ""
background_color: 0.18, .5, .92, 1
pos_hint: { 'top' : 0.65}
size_hint: .1, .3
#on_release:
Widget:
size_hint: .02, 1
BoxLayout:
orientation: 'horizontal'
size_hint: 1, .2
canvas.before:
Color:
rgb: 0.18, .5, .92
Rectangle:
pos: self.pos
size: self.size
Label:
text:'Food'
color: (1, 1, 1, 1)
Label:
text:'Calories'
color: (1, 1, 1, 1)
ScrollView:
scroll_timeout: 250
scroll_distance: 20
do_scroll_y: True
do_scroll_x: False
GridLayout:
id: grid
cols: 2
spacing: 10
padding: 10
Label:
text:'Food'
color: (1, 1, 1, 1)
Label:
text:'Calories'
color: (1, 1, 1, 1)
''')
class temprecipeapp(App):
def build(self):
return root_widget
if __name__ == "__main__":
temprecipeapp().run()
滚动视图中的白色食物和卡路里标签就是例子。理想情况下，它们会浮动到顶部，然后我可以从下拉列表中选择一个新选项，并为队列添加更多选项。我该怎么做？目前，如果我在滚动视图中添加了大量标签，则滚动不会启用。
答案 0 :(得分：1)
要创建一个适合两列的项目food和calories，它可能是最好的＃34;复制＆＃34;表标题中的行为，即Food和Calories，并为FoodItem创建一个单独的容器，这只是BoxLayout。
FoodItem将有两个StringProperties：
您可以通过root.food，root.calories
现在直接在kv中创建这样的项目并将其放入ScrollView，您需要Factory，默认情况下不可用，因此导入。有了这个你基本上可以这样做：
Factory.MyWidget()
并且它会创建您的小部件的实例，您需要将其传递给GridLayout的{{1}}方法。
代码编辑：
add_widget另外，请考虑使用Spinner代替纯...
from kivy.properties import StringProperty
...
root_widget = Builder.load_string('''
#:import FadeTransition kivy.uix.screenmanager.FadeTransition
#:import Factory kivy.factory.Factory # <- import Factory
...
DropDown:
id: dropdown
# on_parent: self.dismiss() <- don't do this
on_select: btn.text = '{}'.format(args[1])
Button:
text: 'Simple Cheese Omelette'
size_hint_y: None
height: '48dp'
on_release: dropdown.select('First Item')
Button:
text: 'Burger'
size_hint_y: None
height: '48dp'
on_release: dropdown.select('Second Item')
Button:
text: 'Tomato and Caper Linguine'
size_hint_y: None
height: '48dp'
on_release: dropdown.select('Third Item')
Button:
text: '+'
font_size: 30
background_normal: ""
background_color: 0.18, .5, .92, 1
pos_hint: { 'top' : 0.65}
size_hint: .1, .3
on_release: grid.add_widget(Factory.FoodItem(food=btn.text, calories='10')) <- add a new item
...
ScrollView:
scroll_timeout: 250
scroll_distance: 20
do_scroll_y: True
do_scroll_x: False
GridLayout:
id: grid
cols: 1 <- change cols
size_hint_y: None
height: self.minimum_height <- make the layout resize itself
spacing: 10
padding: 10
<FoodItem>:
size_hint_y: None
height: 20 <- set a size for the item
Label:
text: root.food
color: (1, 1, 1, 1)
Label:
text: root.calories
color: (1, 1, 1, 1)
''')
class FoodItem(BoxLayout):
food = StringProperty('')
calories = StringProperty('')
...
，因为它可以让事情变得更轻松（并且您将避免Dropdown行为）。