Python 3.4 tkinter实时温度控制

Question

我用python3.4（用tkintergui）编写了复杂的程序。它是实时的温度转换器（摄氏度到华氏度并反转）。它的效果几乎很好，但有一个问题。每次输入值后都要加一个空格。有人知道这个节目出了什么问题吗？在

from tkinter import *

def cel_na_fahr(event):
    e = ".0"
    a = float(ent1.get())
    a = round((32+9/5*a),2)
    a = str(a)
    if a.endswith(e):
        a=a.replace(".0","")
        ent2.delete(0,END)
        ent2.insert(0,a+event.char)
    else:
        ent2.delete(0,END)
        ent2.insert(0,a+event.char)

def fahr_na_cel(event):
    e = ".0"
    a = float(ent2.get())
    a = round(5/9*(a-32),2)
    a = str(a)
    if a.endswith(e):
        a=a.replace(".0","")
        ent1.delete(0,END)
        ent1.insert(0,a+event.char)
    else:
        ent1.delete(0,END)
        ent1.insert(0,a+event.char)

root = Tk()

root.geometry("300x180+400+400")

fr1 = Frame(root, padx=5, pady=40)
fr1.pack(side=TOP)

fr2 = Frame(root)
fr2.pack(side=TOP)

lbl1 = Label(fr1, text="cel to fahr   ")
lbl1.pack(side=LEFT)

ent1 = Entry(fr1) 
ent1.pack(side=RIGHT)

lbl2 = Label(fr2, text="fahr to cel   ")
lbl2.pack(side=LEFT)

ent2 = Entry(fr2) 
ent2.pack(side=RIGHT)

ent1.bind('<Key>', cel_na_fahr)
ent2.bind('<Key>', fahr_na_cel) 

root.mainloop()

Answer 1

必须键入空格，因为当<Key>回调触发时，用户最近按下的键还没有添加到条目中。这可能是您试图通过添加event.char来弥补的，尽管您在错误的地方这样做了。在

将绑定更改为KeyRelease，这样回调会在更新条目之后触发，并删除{}内容，因为您不再需要它了。在

from tkinter import *

def cel_na_fahr(event):
    print(ent1.get())
    e = ".0"
    a = float(ent1.get())
    a = round((32+9/5*a),2)
    a = str(a)
    if a.endswith(e):
        a=a.replace(".0","")
        ent2.delete(0,END)
        ent2.insert(0,a)
    else:
        ent2.delete(0,END)
        ent2.insert(0,a)

def fahr_na_cel(event):
    print(ent2.get())
    e = ".0"
    a = float(ent2.get())
    a = round(5/9*(a-32),2)
    a = str(a)
    if a.endswith(e):
        a=a.replace(".0","")
        ent1.delete(0,END)
        ent1.insert(0,a)
    else:
        ent1.delete(0,END)
        ent1.insert(0,a)

root = Tk()

root.geometry("300x180+400+400")

fr1 = Frame(root, padx=5, pady=40)
fr1.pack(side=TOP)

fr2 = Frame(root)
fr2.pack(side=TOP)

lbl1 = Label(fr1, text="cel to fahr   ")
lbl1.pack(side=LEFT)

ent1 = Entry(fr1) 
ent1.pack(side=RIGHT)

lbl2 = Label(fr2, text="fahr to cel   ")
lbl2.pack(side=LEFT)

ent2 = Entry(fr2) 
ent2.pack(side=RIGHT)

ent1.bind('<KeyRelease>', cel_na_fahr)
ent2.bind('<KeyRelease>', fahr_na_cel) 

root.mainloop()