如何简单地更改 kivy 中标签的文本？

Question

如何更新标签中的文本？

a=Label(text='60')
self.add_widget(a)

虽然代码是运行我如何将 60 更改为另一个数字，例如 50。

我试过这样更改文本：

a=Label(text='60')
self.add_widget(a)
time.sleep(5)
a=Label(text='50')
self.add_widget(a)

但这似乎不起作用。

Answer 1

您的代码创建了两个不同的 Label 小部件并将它们添加到小部件树中。如果您想更改以前创建的小部件的特定属性：

# Create Label and reference it to var 'a'
a = Label(text='60')
self.add_widget(a)
time.sleep(5)
# You can use the 'a' var to access the previously created Label
# and modify the text attribute
a.text = '50'

编辑：为了延迟更改标签文本属性，请使用 Clock 而不是 time（最后一个会在计时器结束时冻结您的应用程序）

from kivy.clock import Clock

def update_label(label_widget, txt):
     label_widget.text = txt

# Create Label and reference it to var 'a'
a = Label(text='60')
self.add_widget(a)

# In five seconds, the update_label function will be called 
# changing the text property of the 'a' Label to "50"
Clock.schedule_once(lambda x: update_label(a, "50"), 5)

EDIT2：带倒计时的标签

要定期更改标签，您可以使用 Clock.schedule_interval

from kivy.clock import Clock

def countdown(label_widget):
     # Convert label text to int. Make sure the first value
     # is always compliant
     num = int(label_widget.text)

     # If the counter has not reach 0, continue the countdown
     if num >= 0:
         label_widget.text = str(num - 1)
     # Countdown reached 0, unschedulle this function using the 
     # 'c' variable as a reference 
     else:
         Clock.unschedule(c)

# Create Label and reference it to var 'a'
a = Label(text='60')
self.add_widget(a)

# Every 1 second, call countdown with the Label instance
# provided as an argument
c = Clock.schedule_interval(lambda x: countdown(a), 1)

如何简单地更改 kivy 中标签的文本？

How to simply change text of a label in kivy?

kivy

kivy-language