运行时kinter窗口是空白的

Question

当我运行用Adafruit测量温度的tkinter代码时。当我运行代码时，tkinter打开一个窗口，但窗口上没有显示任何内容。我以前用过一些tkinter，我让应该出现的东西出现了，但不是在这个特定的代码中。

#!/usr/bin/python
# -*- coding: latin-1 -*-
import Adafruit_DHT as dht
import time
from Tkinter import *
root = Tk()
k= StringVar()
num = 1
thelabel = Label(root, textvariable=k)
thelabel.pack
def READ():
    h,t = dht.read_retry(dht.DHT22, 4)
    newtext = "Temp=%s*C Humidity=%s" %(t,h)
    k.set(str(newtext))
    print newtext #I added this line to make sure that newtext actually had the values I wanted
def read30seconds():
    READ()
    root.after(30000, read30seconds)
read30seconds()
root.mainloop()

并且为了澄清READ中的打印行确实按预期每30秒运行一次

Answer 1

这是因为您没有将其打包在窗口中，而是在python shell中打印。

你应该将print newtext替换为:

w = Label(root, text=newtext)
w.pack() 

工作代码应该是这样的:

#!/usr/bin/python
# -*- coding: latin-1 -*-
import Adafruit_DHT as dht
import time
from Tkinter import *
root = Tk()
k= StringVar()
num = 1
thelabel = Label(root, textvariable=k)
thelabel.pack
def READ():
    h,t = dht.read_retry(dht.DHT22, 4)
    newtext = "Temp=%s*C Humidity=%s" %(t,h)
    k.set(str(newtext))
    w = Label(root, text=newtext)
    w.pack() 

def read30seconds():
    READ()
    root.after(30000, read30seconds)
read30seconds()
root.mainloop()

注意，这是一个非常基本的图形化代码。要了解有关此主题的更多信息，请访问此tkinter标签教程要了解更多关于tkinter本身的信息，请访问tkinter的介绍

如果你想让标签每次刷新时都被覆盖，你应该使用destroy()方法来删除，然后像这样替换标签:

#!/usr/bin/python
# -*- coding: latin-1 -*-
import Adafruit_DHT as dht
import time
from Tkinter import *
root = Tk()
k= StringVar()
num = 1
thelabel = Label(root, textvariable=k)
thelabel.pack
def READ():
    global w
    h,t = dht.read_retry(dht.DHT22, 4)
    newtext = "Temp=%s*C Humidity=%s" %(t,h)
    k.set(str(newtext))
    print newtext #I added this line to make sure that newtext actually had the values I wanted
def read30seconds():
    READ()
    try: w.destroy()
    except: pass
    root.after(30000, read30seconds)
read30seconds()
root.mainloop()