HOST = listing[0]
SUBJECT = listing[1]
FROM = listing[2]

userName = listing[3]
passWord = listing[4]
fileText = listing[5]

s_email = listing[6].split()
server = smtplib.SMTP_SSL(HOST, 465)
server.login(userName, passWord)

max_email = len(s_email)

for i in s_email:
    msg = MIMEMultipart()
    msg['From'] = FROM
    msg['Subject'] = SUBJECT
    msg['To'] = str(i)
    msg.attach(MIMEText(fileText, 'plain'))
    server.send_message(msg)
    v_pb +=1

server.quit()

def build(self):

    gl = GridLayout()

    host_txt = TextInput(multiline=False)
    sub_txt = TextInput(multiline=False)
    from_txt = TextInput(multiline=False)
    user_txt = TextInput(multiline=False)
    pass_txt = TextInput(multiline=False)
    msg_txt = TextInput(font_size=24)
    mail_txt = TextInput(font_size=24)

    btn_start = Button(text="Start",on_press=lambda *a: sendMail(
    listing=(host_txt.text, sub_txt.text, from_txt.text, user_txt.text, pass_txt.text, msg_txt.text, mail_txt.text)))



    progress_bar = ProgressBar(max=max_email, size_hint=(1, .1)) # получить доступ к этой переменной из def sendMail(listing):
    progress_bar.value = v_pb                                    # получить доступ к этой переменной из def sendMail(listing):

    gl.add_widget(host_txt)
    gl.add_widget(sub_txt)
    gl.add_widget(from_txt)
    gl.add_widget(user_txt)
    gl.add_widget(pass_txt)
    gl.add_widget(msg_txt)
    gl.add_widget(mail_txt)
    bl2.add_widget(btn_start)

    gl.add_widget(progress_bar)

    return gl