所以我在尝试使用屏幕管理器时遇到了问题。因为我必须创建我的屏幕类现在是 (Screen) 而不是 (GridLayout) 才能完全使用屏幕管理器，例如，按钮/布局管理不能再在 python 中控制了吗？它曾经在屏幕上布置 5 列和 3 行，总共 15 个按钮。现在它只显示一个大的(屏幕)而不是网格布局。
class LandingScreen(Screen):
def build(self):
return presentation
def __init__(self, **kwargs):
super(LandingScreen, self).__init__(**kwargs)
self.cols = 5
self.buttons = [] # add references to all buttons here
# Loop to make 20 different buttons on screen
for x in range(15):
self.buttons.append(Button(text='button ' + str(x))) # make a reference to the button before adding it in
self.add_widget(self.buttons[x])
self.buttons[x].background_normal = 'YOUTUBE.png'
此处的按钮和列设置用于使用此循环创建 3 行，每行 5 个按钮，但由于我将 (Screen) 添加到类而不是 (GridLayout)，所以不会。我宁愿不在 .kv 文件中创建所有按钮，因为我认为在 .py 中更容易管理并且对我来说更有意义。
这是我的 .kv 文件:
<GridLayout>:
cols: 5
height: 480
width: 800
spacing: 25, 20
padding: 25,25
<MyScreenManager>:
LandingScreen:
InputScreen:
<InputScreen>:
AnchorLayout:
<LandingScreen>:
GridLayout:
cols: 5
height: 480
width: 800
spacing: 25, 20
padding: 25,25
这显然是多余的，因为我试图弄清楚如何让所有 15 个按钮再次显示，而不仅仅是一个。
谢谢!
最佳答案
您想将按钮添加到 Screen 内的 GridLayout，而不是直接添加到 Screen。为此，请使用 id 来引用 GridLayout。
但是，您不能在 __init__ 方法中使用 id，因为在完全初始化相应的小部件之前，不会应用 kv 文件中定义的规则。 Ryan Pi 在这个问题中正确提供了解决方案:
Why can't I access the Screen.ids?
另一方面，要稍后更改屏幕，您必须在您的屏幕中定义 name 属性。
您的代码应该是:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.button import Button
from kivy.clock import Clock
kv_text='''\
<MyScreenManager>:
LandingScreen:
InputScreen:
<InputScreen@Screen>:
name: 'input_sc'
AnchorLayout:
id: anchor_1
<LandingScreen@Screen>:
name: 'landing_sc'
GridLayout:
id: grid_1
cols: 5
height: 480
width: 800
spacing: 25, 20
padding: 25,25
'''
class MyScreenManager(ScreenManager):
pass
class LandingScreen(Screen):
def __init__(self, **kwargs):
super(LandingScreen, self).__init__(**kwargs)
self.buttons = [] # add references to all buttons here
Clock.schedule_once(self._finish_init)
def _finish_init(self, dt):
self.ids.grid_1.cols = 5
# Loop to make 20 different buttons on screen
for x in range(15):
self.buttons.append(Button(text='button {}'.format(x)))
self.ids.grid_1.add_widget(self.buttons[x])
self.buttons[x].background_normal = 'YOUTUBE.png'
class MyKivyApp(App):
def build(self):
return MyScreenManager()
def main():
Builder.load_string(kv_text)
app = MyKivyApp()
app.run()
if __name__ == '__main__':
main()
如果你想使用 Properties 而不是 ids 方法(参见 documentation )，你应该这样做:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.button import Button
from kivy.clock import Clock
from kivy.properties import ObjectProperty
kv_text='''\
<MyScreenManager>:
LandingScreen:
InputScreen:
<InputScreen@Screen>:
name: 'input_sc'
AnchorLayout:
id: anchor_1
<LandingScreen@Screen>:
name: 'landing_sc'
grid_1: grid_1
GridLayout:
id: grid_1
cols: 5
height: 480
width: 800
spacing: 25, 20
padding: 25,25
'''
class MyScreenManager(ScreenManager):
pass
class LandingScreen(Screen):
grid_1 = ObjectProperty(None) #<<<< Propertie
def __init__(self, **kwargs):
super(LandingScreen, self).__init__(**kwargs)
self.buttons = [] # add references to all buttons here
Clock.schedule_once(self._finish_init)
def _finish_init(self, dt):
self.grid_1.cols = 5
# Loop to make 20 different buttons on screen
for x in range(15):
self.buttons.append(Button(text='button{}'.format(x)))
self.grid_1.add_widget(self.buttons[x])
self.buttons[x].background_normal = 'star.png'
class MyKivyApp(App):
def build(self):
return MyScreenManager()
def main():
Builder.load_string(kv_text)
app = MyKivyApp()
app.run()
if __name__ == '__main__':
main()
关于python - 将 ScreeManager 与 Kivy- 按钮布局一起使用时的问题不再有效，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44837609/