每当我选择微调器值时如何隐藏标签？

Question

1. {实际上每当我点击微调器值（官方）标签时 创建，当时我点击另一个微调器值“正常” 创建的标签被隐藏。这种情况工作正常，但来到我的 第二种情况——每当我首先点击微调器值（正常）时 时间，显示错误}

   进口kivy kivy.require('1.10.0') 从 kivy.core.window 导入窗口 从 kivy.app 导入应用程序 从 kivy.uix.floatlayout 导入 FloatLayout 从 kivy.uix.label 导入标签 从 kivy.graphics 导入颜色、矩形 从 kivy.uix.textinput 导入 TextInput 从 kivy.uix.spinner 导入微调器

   Window.size = (500, 400) Window.clearcolor = (0.1, 0.1, 0.3, 0.2)

   def show_selected_value（微调器，文本）： print('选定进程', spinner, '有文本', text)

   类 LRefConfigAutomation(App): 配置=无

   def build_config(self, config):
       config.setdefaults('LefConfigWindowSection', {
           'PartInputLabel': 'Please Enter your Part No',
           'TypeOfProcessLabel': 'Select Type Of Process',
           'NormalFolderName': 'Enter Normal Folder Name',
   
       })
       self.config = config
   
   def build(self):
       config = self.config
       root = FloatLayout()
       lbl = config.get('LefConfigWindowSection', 'PartInputLabel')
       self.label01 = Label(text=lbl, pos_hint={"center_x": .66, "center_y": .90}, size_hint=(1.0, 1.0), halign="left",
                            valign="middle", font_name='Georgia')
       self.label01.bind(size=self.label01.setter('text_size'))
       self.label01.font_size = '14.5dp'  # something that'll give texture bigger than phone's screen size
       root.add_widget(self.label01)
       with self.label01.canvas:
           Color(0, 0, 0, 0)
           Rectangle(pos=self.label01.pos, size=self.label01.size)
       self.txtKemNo = TextInput(pos_hint={"center_x": .66, "center_y": .90}, size_hint=(None, None),
                                 font_name="Georgia", size=(100, 30), multiline=False, hint_text="Part Number")
       root.add_widget(self.txtKemNo)
       lbl = config.get('LefConfigWindowSection', 'TypeOfProcessLabel')
       self.label02 = Label(text=lbl, pos_hint={"center_x": .66, "center_y": .75}, size_hint=(1.0, 1.0), halign="left",
                            valign="middle", font_name='Georgia')
       self.label02.bind(size=self.label02.setter('text_size'))
       self.label02.font_size = '14.5dp'  # something that'll give texture bigger than phone's screen size
       root.add_widget(self.label02)
       with self.label02.canvas:
           Color(0, 0, 0, 0)
           Rectangle(pos=self.label02.pos, size=self.label02.size)
       self.requestsspinner = Spinner(
           # default value shown
           text='Select Process',
           # available values will be binded to the combo
           values=("Normal", "Official"),
           # just for positioning in our example
           size_hint=(None, None),
           size=(110, 20),
           pos_hint={'center_x': .66, 'center_y': .75}, font_name='Georgia')
       self.requestsspinner.font_size = '14.5dp'
       self.requestsspinner.bind(text=show_selected_value)
       self.requestsspinner.bind(text=self.CreateLable)
       root.add_widget(self.requestsspinner)
   
       return root
   
   def CreateLable(self, spinner, text):
       config = self.config
       if text == "Official":
           lbl = config.get('LefConfigWindowSection', 'NormalFolderName')
           self.label03 = Label(text=lbl, pos_hint={"center_x": .66, "center_y": .65}, size_hint=(1.0, 1.0),
                                halign="left", valign="middle", font_name='Georgia')
           self.label03.bind(size=self.label03.setter('text_size'))
           self.label03.font_size = '14.5dp'
           self.root.add_widget(self.label03)
           with self.label03.canvas:
               Color(0, 0, 0, 0)
               Rectangle(pos=self.label03.pos, size=self.label03.size)
       elif text == "Normal":
           self.label03.text = ""
   

   如果 name == "ma​​in"： LRefConfigAutomation().run()

Answer 1

在 CreateLabel 中，您需要将创建部分移到 if 条件之外： 所以这部分

lbl = config.get('LefConfigWindowSection', 'NormalFolderName')
        self.label03 = Label(text=lbl, pos_hint={"center_x": .66, "center_y": .65}, size_hint=(1.0, 1.0),
                                 halign="left", valign="middle", font_name='Georgia')
        self.label03.bind(size=self.label03.setter('text_size'))
        self.label03.font_size = '14.5dp'
        self.root.add_widget(self.label03)

应该在if text == "Official": 之前。 否则，您会收到错误消息，因为您尚未创建 self.label03。 完成 CreateLabel：

def CreateLable(self, spinner, text):
        config = self.config
        lbl = config.get('LefConfigWindowSection', 'NormalFolderName')
        self.label03 = Label(text=lbl, pos_hint={"center_x": .66, "center_y": .65}, size_hint=(1.0, 1.0),
                                 halign="left", valign="middle")
        self.label03.bind(size=self.label03.setter('text_size'))
        self.label03.font_size = '14.5dp'
        self.root.add_widget(self.label03)
        if text == "Official":            
            with self.label03.canvas:
                Color(0, 0, 0, 0)
                Rectangle(pos=self.label03.pos, size=self.label03.size)
        elif text == "Normal":
            self.label03.text = ""

---

CreateLabel 中还有一个问题：

self.label03 = Label(...)

每次调用 CreateLabel 时，都会为 self.label03 分配一个新标签，而不是第一个。所以不是隐藏第一个，而是创建一个新的并隐藏它。有多种解决方法，但这里有一种：

def build(self):
    ... # add these two lines to create the Label once
    self.CreateLabel()  
    root.add_widget(self.label03)
    # Use another function (UpdateLabel) to update the value
    self.requestsspinner.bind(text=show_selected_value)
    self.requestsspinner.bind(text=self.UpdateLable)
    ...

# Only called once to create the Label
def CreateLabel(self):
    self.label03 = Label(text="", pos_hint={"center_x": .66, "center_y": .65}, size_hint=(1.0, 1.0),
                             halign="left", valign="middle")
    self.label03.bind(size=self.label03.setter('text_size'))
    self.label03.font_size = '14.5dp' 
    with self.label03.canvas:
        Color(0, 0, 0, 0)
        Rectangle(pos=self.label03.pos, size=self.label03.size)

# Changes the Label 
def UpdateLable(self, spinner, text):        
    if text == "Official":
        config = self.config
        self.label03.text =  config.get('LefConfigWindowSection', 'NormalFolderName')            
    elif text == "Normal":
        self.label03.text = ""