为什么我不能访问Screen.ids? [英] Why can't I access the Screen.ids?
问题描述
更新:
Ryan P的答案提供了解决方案.但是,我采取了该解决方案 并对其进行了一些修改,从而丢弃了所有未得到的数据 正确初始化为RootWidget的on_enter方法 屏幕.效果很好.
Ryan P's answer provided the solution. However, I took that solution and changed it up a bit, throwing all of the data that wasn't being properly initialised into the on_enter method of the RootWidget Screen. This has worked nicely.
直到今天,我的RootWidget类仍将Widget子类化,并且我可以很方便地访问其id以获取"grid"的值.但是,我只是改变了 它子类到Screen,现在它说id是空的,由于某种原因... Screen确实有一个id和所有的东西,但是由于某种原因,它没有注册 我将GridLayout分配给kv文件中的ID"grid".谁能告诉我为什么?
My RootWidget class was subclassing Widget until today, and I had no problem accessing it's ids to get the value of "grid". However, I just changed it to subclass Screen, and now it says the ids is empty for some reason... Screen does have an ids and all that, but for some reason, it isn't registering that I assigned a GridLayout to the id ''grid'' in the kv file. Can anyone tell me why?
追溯:
[INFO ] [Logger ] Record log in /home/yerman/.kivy/logs/kivy_14-11-13_201.txt
[INFO ] Kivy v1.9.0-dev
[INFO ] [Python ] v2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2]
[INFO ] [Factory ] 172 symbols loaded
[INFO ] [Image ] Providers: img_tex, img_dds, img_pygame, img_pil, img_gif (img_sdl2, img_ffpyplayer ignored)
[INFO ] [Window ] Provider: pygame(['window_egl_rpi'] ignored)
[WARNING] [WinPygame ] Video: failed (multisamples=2)
[WARNING] [WinPygame ] trying without antialiasing
[INFO ] [GL ] OpenGL version <2.1 Mesa 10.1.3>
[INFO ] [GL ] OpenGL vendor <Intel Open Source Technology Center>
[INFO ] [GL ] OpenGL renderer <Mesa DRI Intel(R) Ironlake Mobile >
[INFO ] [GL ] OpenGL parsed version: 2, 1
[INFO ] [GL ] Shading version <1.20>
[INFO ] [GL ] Texture max size <8192>
[INFO ] [GL ] Texture max units <16>
[INFO ] [Window ] virtual keyboard not allowed, single mode, not docked
[INFO ] [Text ] Provider: pygame(['text_sdl2'] ignored)
{} #<<< note the emtpy ids I printed out
Traceback (most recent call last):
File "main.py", line 169, in <module>
MineSweeperApp().run()
File "/usr/lib/python2.7/dist-packages/kivy/app.py", line 799, in run
root = self.build()
File "main.py", line 163, in build
return Manager()
File "/usr/lib/python2.7/dist-packages/kivy/uix/screenmanager.py", line 844, in __init__
super(ScreenManager, self).__init__(**kwargs)
File "/usr/lib/python2.7/dist-packages/kivy/uix/floatlayout.py", line 66, in __init__
super(FloatLayout, self).__init__(**kwargs)
File "/usr/lib/python2.7/dist-packages/kivy/uix/layout.py", line 66, in __init__
super(Layout, self).__init__(**kwargs)
File "/usr/lib/python2.7/dist-packages/kivy/uix/widget.py", line 269, in __init__
Builder.apply(self)
File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 1837, in apply
self._apply_rule(widget, rule, rule)
File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 1942, in _apply_rule
child = cls(__no_builder=True)
File "main.py", line 43, in __init__
self.grid = self.ids["grid"]
KeyError: 'grid'
kv文件:
#:kivy 1.8.0
<RootWidget>:
GridLayout:
id: grid
size: root.size
cols: root.sides
<Blank>:
background_color: 1, 1, 1, 1
background_disabled_down: "kivy_white_bg.png"
on_press: self.parent.parent.sweep(self)
<Mine>:
background_color: 1, 1, 1, 1
background_disabled_down: "kivy_white_bg.png"
on_press: self.parent.parent.sweep(self)
<TryAgain>:
anchor_x: 'center'
anchor_y: 'center'
BoxLayout:
size: root.size
orientation: 'vertical'
padding_bottom: '20dp'
Label:
font_size: '20dp'
text: root.text
BoxLayout:
size_hint: 1, .3
spacing: 10
padding: 10
Button:
size_hint: .4, 1
font_size: '20dp'
text: "yes"
on_press: app.stop(); app.run()
Button:
size_hint: .4, 1
font_size: '20dp'
text: "no"
on_press: root.quit()
<Menu>:
GridLayout:
rows: 2
Button:
text: "8x8"
on_press: root.manager.current = 'game_screen'
Button:
text: "16x16"
on_press: root.manager.current = 'game_screen'
Button:
text: "30x16"
on_press: root.manager.current = 'game_screen'
Button:
text: "custom"
on_press: root.manager.current = 'game_screen'
<Manager>:
id: _manager
menu: menu
game: game
current: menu_screen
Menu:
id: menu
manager: _manager
name: 'menu_screen'
RootWidget:
id: game
manager: _manager
name: 'game_screen'
main.py:
#!/usr/bin/env python
from random import sample
import sys
import kivy
kivy.require('1.8.0')
from kivy.app import App
from kivy.core.window import Window
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.properties import NumericProperty, ListProperty, StringProperty, ObjectProperty
from kivy.uix.gridlayout import GridLayout
from kivy.uix.modalview import ModalView
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.clock import Clock
class Blank(Button):
index = ListProperty([0, 0])
count = NumericProperty(0)
def __init__(self, **kwargs):
super(Blank, self).__init__(**kwargs)
class Mine(Button):
index = ListProperty([0, 0])
count = NumericProperty(0) # not really necessary
def __init__(self, **kwargs):
super(Mine, self).__init__(**kwargs)
class RootWidget(Screen):
sides = NumericProperty(10)
mine_count = NumericProperty(20)
def __init__(self, **kwargs):
super(RootWidget, self).__init__(**kwargs)
self.grid = self.ids["grid"]
# generate random mine indices
mines = sample(xrange(self.sides**2), self.mine_count)
x, y = -1, 0
for i in xrange(self.sides**2):
if x == self.sides - 1:
x = 0
y += 1
else:
x += 1
if i not in mines:
b = Blank(index=[x, y])
else:
b = Mine(index=[x, y])
self.grid.add_widget(b)
# record mine, blank and safe blank indices
self.all_btns = [c.index for c in self.grid.children]
self.mines = [c.index for c in self.grid.children if isinstance(c, Mine)]
self.blanks = [c.index for c in self.grid.children if isinstance(c, Blank)]
# a safe blank has no adjacent mines
self.safe_blanks = [c.index for c in self.grid.children if self.is_safe(c)]
# give each btn an 'adjacent mines count'
for x, y in self.all_btns:
btn = self.get_child_by_index([x, y])
for index in self.field(x, y):
if index in self.mines:
btn.count += 1
def field(self, x, y):
""" the minefield surrounding a btn """
field = [[x-1, y], [x+1, y], [x, y+1], [x, y-1],
[x+1, y+1], [x-1, y-1], [x+1, y-1], [x-1, y+1]]
get = self.get_child_by_index
return [i for i in field if i in self.all_btns and get(i).disabled == False]
def sweep(self, instance):
instance.disabled = True
if instance.index in self.mines:
print "Boom!" # It's a mine! You lose
instance.text = "Boom!"
self.game_over()
pressed = sum(1 for c in self.grid.children if c.disabled == True)
print pressed
if self.sides**2 - pressed == self.mine_count:
self.game_over(win=True)
if instance.count > 0:
instance.text = str(instance.count)
instance.disabled = True
return
else:
x, y = instance.index
for index in self.field(x, y):
if index not in self.mines:
blank = self.get_child_by_index(index)
blank.disable = True
if blank.count > 0:
blank.text = str(blank.count)
self.sweep(blank)
def is_safe(self, btn):
x, y = btn.index
for index in self.field(x, y):
if index in self.mines:
return False
return True
def get_child_by_index(self, index):
for child in self.grid.children:
if child.index == index:
return child
def game_over(self, q=False, win=False):
if q == True:
sys.exit()
if win == True:
result = "Win"
elif win == False:
result = "lost"
view = TryAgain(
size_hint = (None, None),
width = self.width/2,
height = self.height/2,
center = self.center,
text = "You {}! Try Again?".format(result))
view.open()
class TryAgain(ModalView):
text = StringProperty('')
def quit(self):
sys.exit()
class Menu(Screen):
pass
class Manager(ScreenManager):
menu = ObjectProperty(None)
game = ObjectProperty(None)
class MineSweeperApp(App):
def build(self):
return Manager()
if __name__ == "__main__":
MineSweeperApp().run()
推荐答案
在原始Widget
完成实例化之前,不会应用kv规则.在这种情况下,您的Manager
小部件是初始小部件-依次创建其他小部件,包括RootWidget
.这意味着RootWidget.__init__
中的ids
尚未填充!它们将尽快完成Manager
的实例化-因此,最好的方法是延迟其余的初始化,如下所示:
kv rules are not applied until the original Widget
has finished instantiating. In this case, your Manager
widget is the initial widget - it, in turn, creates the other widgets including RootWidget
. This means that in your RootWidget.__init__
the ids
are not yet populated! They will be as soon as Manager
finishes instantiating - so the best approach is to just delay the rest of your initialization, like so:
class RootWidget(Screen):
def __init__(self, **kwargs):
super(RootWidget, self).__init__(**kwargs)
Clock.schedule_once(self._finish_init)
def _finish_init(self, dt):
self.grid = self.ids.grid
# etc
这篇关于为什么我不能访问Screen.ids?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!