假设我有一个 id:fruit 和值 "apple","banana","watermelon" 的微调器。
我有一些类似的代码：
if(self.ids['fruit'].text=='apple'):
a=2
现在，在我的应用程序中，我有一个语言选择选项。因此，如果我选择“西班牙语”，我会将苹果更改为西班牙语，我上面的代码将失败（id 将仅保留为英文，因为我不会更改它）。但是所选值的索引将保持不变。
那么，kivy spinner 是否有索引支持，我的意思是：
if(self.ids['fruit'].id==1):
a=2
【问题讨论】：
标签： python kivy kivy-language
为了将值（和当前选择）与显示的文本分开，我编写了Spinner 的子类。它将显示值 (values) 与值的逻辑表示 (hidden_values) 分开。此外，它还有一个额外的属性text_transformer，可以将selected_text（values的当前项）和selected_value（hidden_values的当前项）转换为显示文本。该代码也包含一个示例。对于我的原始版本（带有原始示例），请查看this gist。
# -*- coding: utf-8 -*-
import itertools
from kivy.factory import Factory
from kivy.compat import string_types
from kivy.uix.spinner import Spinner, SpinnerOption
from kivy.properties import ListProperty, ObjectProperty, StringProperty
from kivy.logger import Logger
class HVSpinnerOption(SpinnerOption):
"""Represents an option in HVSpinner. It adds :attr:`value` to represent a hidden value not shown to user."""
value = ObjectProperty(None)
class HVSpinner(Spinner):
"""Implements a spinner that keeps hidden values associated with
options and displays a human readable text.
"""
hidden_values = ListProperty()
"""Values associated with every item generated from :attr:`values`.
:attr:`hidden_values`: is a :class:`~kivy.properties.ListProperty` and defaults to `range(len(self.values))`.
The list may contain any kind of object.
"""
selected_text = StringProperty()
"""Text representation of the selected item. By default, this is `None`. Upon selection of an item,
it will be the corresponding element of :attr:`values`.
"""
selected_value = ObjectProperty(None)
"""Representation of the selected item. Defaults to `None`. Upon selection of an item,
it will be the corresponding element of :attr:`hidden_values`.
"""
option_cls = ObjectProperty(HVSpinnerOption)
'''Extension of class to display options. It must conform to requirements laid out for :attr:`~kivy.uix.spinner.option_cls`. In addition, the class must have a `value` property (should be :class:`~kivy.properties.ObjectProperty`).
Additional :parameter:
`text_transformer`: `None` or `callable`. Function that is used to set the :attr:`text` of :class:`HVSpinner` once
an item has been selected. It should return a string and it should take 3 arguments:
- :attr:`caller`: instance of :class:`HVSpinner` making the call
- :attr:`text`: same as :attr:`selected_text`
- :attr:`value`: same as :attr:`selected_value`
Example::
from kivy.base import runTouchApp
from kivy.uix.gridlayout import GridLayout
from kivy.uix.boxlayout import BoxLayout
def print_current_val(obj, *largs):
print "Spinner {} has text [{}], selected_text [{}] and hidden value [{}]".format(obj, obj.text, obj.selected_text, obj.selected_value)
def transformator(caller, text, value):
return "Now at >{}< ({})".format(text, value)
vals = ["item {}".format(i) for i in range(8)]
hvals = ["<{}>".format(i + 17) for i in range(len(vals)) ]
gl = GridLayout(rows=1)
hvs1 = HVSpinner(values=vals, hidden_values=hvals, text='Select Me',
size_hint=(.3, None), height="30dp")
hvs2 = HVSpinner(values=vals, text='No, Me', size_hint=(.3, None), height="40dp")
hvs3 = HVSpinner(values=vals, hidden_values=range(len(vals)), text='Please, me!', size_hint=(.3, None), height="30dp",
text_transformer=transformator)
hvs1.bind(selected_value=print_current_val)
hvs2.bind(selected_value=print_current_val)
hvs3.bind(selected_value=print_current_val)
gl.add_widget(hvs1)
gl.add_widget(hvs2)
gl.add_widget(hvs3)
runTouchApp(gl)
'''
def __init__(self, *args, **kwargs):
self.text_transformer = kwargs.pop('text_transformer', None)
super(HVSpinner, self).__init__(*args, **kwargs)
def _update_dropdown(self, *largs):
dp = self._dropdown
cls = self.option_cls
if isinstance(cls, string_types):
cls = Factory.get(cls)
dp.clear_widgets()
if len(self.hidden_values) == 0:
self.hidden_values = range(len(self.values))
if len(self.values) != len(self.hidden_values):
Logger.warning("HVSpinner: 'values' and 'hidden_values' have different lengths.")
for tv, hv in itertools.izip(self.values, self.hidden_values):
item = cls(text=tv, value=hv)
item.bind(on_release=lambda option: dp.select((option.text, option.value)))
dp.add_widget(item)
def _on_dropdown_select(self, instance, data, *largs):
if callable(self.text_transformer):
self.text = self.text_transformer(self, data[0], data[1])
else:
self.text = data[0]
self.selected_text = data[0]
self.selected_value = data[1]
self.is_open = False
Factory.register('HVSpinner', cls=HVSpinner)
def main():
from kivy.app import App
from kivy.lang import Builder
from kivy.clock import Clock
kvstr = '''
GridLayout:
cols: 2
HVSpinner:
id: my_spinner
text: "Pick one"
values: ["apple", "banana", "watermelon"]
Button:
text: "Do something with it!"
on_press: app.do_something()
Label:
text: "Current language: {}".format(app.current_language)
Button:
text: "Change Language"
on_press: app.change_language()
'''
item_list = ["apple", "banana", "watermelon"]
item_list_spanish = ["manzana", "banana", "sandía"]
class AnApp(App):
current_language = StringProperty('English')
def build(self):
Clock.schedule_once(self.set_up_spinner, 0)
return Builder.load_string(kvstr)
def change_language(self):
if self.current_language == 'English':
self.current_language = 'Spanish'
self.root.ids.my_spinner.values = item_list_spanish
else:
self.current_language = 'English'
self.root.ids.my_spinner.values = item_list
def set_up_spinner(self, dt=0):
def transformator(caller, text, value):
if self.current_language=='English':
return "You picked: {}".format(text)
else:
return "Escogió: {}".format(text)
self.root.ids.my_spinner.text_transformer = transformator
def do_something(self):
if self.root.ids.my_spinner.selected_value == 0:
print "An apple was picked!"
AnApp().run()
if __name__ == '__main__':
main()
【讨论】：
微调器值在ListProperty 中，因此您可以像这样对它们使用枚举：
for index, text in enumerate(self.ids.fruit.values):
if index == 1:
a=2
即使您不能在 ListProperty 上使用 enumerate，您仍然可以在函数开头从 values 创建自己的列表。当然枚举从零开始，所以如果你想在代码中使用1，index + 1 是必要的。
【讨论】：