Kivy中如何清除文本内容？登录GUI清除功能失效求助

问题根源 #

1. 属性拼写错误：resetType函数里错误使用了txt属性，Kivy的TextInput控件内容对应的属性是text，而非txt，这是导致输入框无法清空的核心原因。
2. 按钮事件冗余且调用错误：CreateWindow的按钮中重复设置了on_press: root.resetType，既没有加括号（无法触发函数执行），且createAccountButton方法里已经调用了resetType，属于冗余代码。

修正后的代码 #

Python代码部分

import kivy
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.floatlayout import FloatLayout
from kivy.properties import ObjectProperty
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang import Builder

class LoginWindow(Screen):
    username = ObjectProperty(None)
    password = ObjectProperty(None)

    def btn(self):
        print(self.username.text, self.password.text)
        # 后续登录验证失败时，可调用以下清除方法
        # self.clear_inputs()
    
    # 新增登录失败清除输入框的方法
    def clear_inputs(self):
        self.username.text = ""
        self.password.text = ""

class CreateWindow(Screen):
    createusername = ObjectProperty(None)
    createpassword = ObjectProperty(None)

    def createAccountButton(self):
        createdusername = str(self.createusername.text)
        createdpassword = str(self.createpassword.text)
        with open("database.txt", "a") as database:
            database.write(createdusername + "," + createdpassword + '\n')
            print("In file now")
            # with语句会自动关闭文件，无需手动调用close()
        self.resetType()
    
    def resetType(self):
        self.createusername.text = ""  # 修正为text属性
        self.createpassword.text = ""
        print("Working")

class RealWindow(Screen):
    pass

class WindowManager(ScreenManager):
    pass

kv = Builder.load_file("login.kv")

class TestApp(App):
    def build(self):
        return kv

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

KV文件部分

WindowManager:
    #: import NoTransition kivy.uix.screenmanager.NoTransition
    transition: NoTransition()
    LoginWindow:
    CreateWindow:
    RealWindow:

<LoginWindow>:
    name: "login"
    username: username
    password: password

    FloatLayout:
        Button:
            text:"Log In"
            size_hint: 0.5, 0.1
            pos_hint: {"x":0.25, "y":0.3}
            on_press: root.btn()
        
        Button:
            text:"Create Account"
            size_hint: 0.3, 0.05
            pos_hint: {"x":0.36, "y":0.20}
            on_release:
                app.root.current = "Create"
        
        TextInput:
            id: password
            size_hint: 0.25, 0.1
            pos_hint: {"x":0.5, "y":0.5}
        
        TextInput:
            id:username
            size_hint: 0.25, 0.1
            pos_hint: {"x":0.5, "y":0.6}
        
        Label:
            font_size: '40'
            text:"Log In"
            size_hint: 0.5, 0.5
            pos_hint: {"x":0.25, "y":0.6}
        
        Label:
            font_size: '25'
            text:"Username:"
            size_hint: 0.5, 0.1
            pos_hint:{"x":0.1,"y":0.6}
        
        Label:
            font_size: '25'
            text:"Password:"
            size_hint: 0.5, 0.1
            pos_hint:{"x":0.1,"y":0.5}

<CreateWindow>:
    name: "Create"

    createusername: createusername
    createpassword: createpassword

    FloatLayout:
        Button:
            text:"Login"
            size_hint: 0.5, 0.1
            pos_hint: {"x":0.25, "y":0.3}
            on_press: root.createAccountButton()
            on_release:
                app.root.current = "login"
        
        TextInput:
            id: createpassword
            size_hint: 0.25, 0.1
            pos_hint: {"x":0.5, "y":0.5}
        
        TextInput:
            id:createusername
            size_hint: 0.25, 0.1
            pos_hint: {"x":0.5, "y":0.6}
        
        Label:
            font_size: '40'
            text:"Create Account"
            size_hint: 0.5, 0.5
            pos_hint: {"x":0.25, "y":0.6}
        
        Label:
            font_size: '25'
            text:"Username:"
            size_hint: 0.5, 0.1
            pos_hint:{"x":0.1,"y":0.6}
        
        Label:
            font_size: '25'
            text:"Password:"
            size_hint: 0.5, 0.1
            pos_hint:{"x":0.1,"y":0.5}

<RealWindow>:
    name: "Real"

内容的提问来源于stack exchange，提问作者asp3ct