如何在kivy中簡單地更改標籤的文字？

Question

我如何更新標籤中的文字？

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

同時運行代碼如何將我60變到另一號碼，例如50

我試圖改變這樣的文字：

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

但這似乎並不上班。

Answer 1

您的代碼創建兩個不同的Label小部件並將它們添加到小部件樹中。如果你想改變以前創建的窗口小部件的特定屬性：

# 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' 

編輯：爲了延緩標籤文本屬性的變化，使用Clock代替time（最後一個將會凍結您的應用程序，而計時器結束）

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：標籤倒計時

要更改您定期的標籤，你可以使用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)