如何使用 if 语句从一个页面重定向到另外两个页面

Question

我想让这个程序从数据库中读取信息，如果正确的话，转到程序的主页否则说信息有误

如何使用 if 语句从一个页面重定向到另外两个页面如果用户输入和密码为 True 按下按钮返回主页否则打印密码或用户错误

应该是从数据库中读取数据

.py

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager,Screen
from kivy.lang import Builder
from kivy import Config


Builder.load_file("kivy.kv")

class AddUser(Screen):
    def changeScreen(self):
        self.ids.Gotologin.on_press = self.manager.transition.direction = 'up'
    def getUserInfo(self):
        name = self.ids.addusername.text
        paswd = self.ids.addpassword.text
        phone = self.ids.addphone.text
        gmail = self.ids.addgmial.text
        if len(paswd) == 0 and len(name) == 0:
            self.ids.passwordles.text = "Enter your name & Password !"
        elif len(paswd) <= 0:
            self.ids.passwordles.text = "Add a Pssword !"
        elif len(paswd) <= 6:
            self.ids.passwordles.text = "Password is too small"
        elif len(name) <= 0:
            self.ids.passwordles.text = "Enter your Name !"


class Home(Screen):

    def add(self):
        name = self.ids.Name.text
        number = self.ids.Number.text
        ID = self.ids.Id.text
        Buy = self.ids.Buy.text
        sale = self.ids.Sale.text
        ex_date = self.ids.exdate.text
        usage = self.ids.Usage.text
        medicine = self.ids.Medicine.text
        Category = self.ids.Catigory.text


class LogIn(Screen):
    def get(self):
        cr.execute("SELECT * FROM login")
        log = cr.fetchall()
        user = self.ids.username.text
        paswd = self.ids.password.text

Screen_Manager = ScreenManager()

Screen_Manager.add_widget(AddUser(name="Adduser"))
Screen_Manager.add_widget(LogIn(name="Login"))
Screen_Manager.add_widget(Home(name="Home"))

# main class to run application
class MainApp(App):
    def build(self):
        return Screen_Manager

if __name__ == "__main__":
    MainApp().run()

.kv

<AddUser>:
    BoxLayout:
        canvas.before:
            Color:
                rgba:0,0,1,1
            Rectangle:
                size:self.size
                pos:self.pos
        orientation:"vertical"
        BoxLayout:
            Label:
                id:passwordles
                text:""
        BoxLayout:
            orientation:'vertical'
            BoxLayout:
                Label:
                    size_hint_x:.22
                    text:""
                Label: 
                    text:"User Name *"
                Label:
                    text:"Password *"
                Label:
                    text:"Phone Number"
                Label:
                    text:"Gmail"
                Label:
                    size_hint_x:.22
            BoxLayout:
                Label:
                    size_hint_x:.22
                    text:""
                TextInput:
                    id:addusername
                    size_hint_y:.5
                    hint_text:"User Name"
                TextInput:
                    id:addpassword
                    size_hint_y:.5
                    password:True
                    hint_text:"Password"
                TextInput:
                    id:addphone
                    size_hint_y:.5
                    hint_text:"Phone Number"
                TextInput:
                    id:addgmial
                    size_hint_y:.5
                    hint_text:"Gmail"
                Label:
                    size_hint_x:.22
            BoxLayout:
                Label:
                    text:""
                Button:
                    id:Gotologin
                    radius: 100, 100, 100, 100
                    font_name:"fonts/MTCORSVA.TTF"
                    color:1,1,0,1
                    outline:0,0,0,1
                    outline_width:4
                    font_size:32
                    bolde:True
                    size_hint_y:.8
                    text:"Login"
                    on_press:
                        root.getUserInfo()
                        root.manager.transition.direction = 'up'
                        root.manager.transition.duration = .9
                        root.manager.current = 'Login'
                Label:
                    text:""
        BoxLayout:
            Label:
                text:""
<LogIn>:
    BoxLayout:
        orientation:'vertical'
        canvas.before:
            Color:
                rgba:0,0,1,1
            Rectangle:
                size:self.size
                pos:self.pos
        BoxLayout:
            Label:
                text:""
        BoxLayout:
            orientation:'horizontal'
            BoxLayout:
                size_hint_x:.4
                Label:
                    text:""
            BoxLayout:
                orientation:"vertical"
                TextInput:
                    id:username
                    size_hint_y:.3
                    hint_text:"User Name"
                TextInput:
                    id:password
                    size_hint_y:.3
                    hint_text:"Password"
                BoxLayout:
                    orientation:"horizontal"
                    Label:
                        size_hint_x:.3
                        text:""
                    Button:
                        id:LoginFromButton
                        on_press:
                            root.manager.transition.direction='left'
                            root.manager.transition.duration = .9
                            root.manager.current = 'Home'
                        text:'Login'
                        font_name:"fonts/MTCORSVA.TTF"
                        color:1,1,0,1
                        outline:0,0,0,1
                        outline_width:4
                        font_size:32
                        bolde:True
                        size_hint_y:.5
                    Label:
                        size_hint_x:.3
                        text:""
            BoxLayout:
                size_hint_x:.4
                Label:
                    text:""

        BoxLayout:
            Label:
                text:""

<Home>:
    Button:
        text:"Home"

Answer 1

在您的 kv 中，将 on_press 设置为方法，如下所示：

                Button:
                    id:LoginFromButton
                    on_press:
                        root.do_login()

然后，在 LogIn 屏幕中 class:

def check_login(self):
    # do your check for legal login and return True or False
    return True

def do_login(self):
    if self.check_login():
        self.manager.current = 'Home'

如何使用 if 语句从一个页面重定向到另外两个页面

how to redirect from one page two other page with an if statement

python

kivy

login-page