在kivy的Python中，如何确定布局管理器的Dropdown的位置？

如何解决在kivy的Python中，如何确定布局管理器的Dropdown的位置？

在基辅1.11.1中。和python3。我在根类中有一个FloatLayout，其中包含一个Label和一个dropdown [text input + RecycleView]，但是当在文本输入中编写示例时，文本输入会向上并隐藏我的标签，我希望它修复后，下拉菜单将下降。我尝试进入refresh_view_layout方法，但没有成功。有任何想法吗 ？？谢谢您的帮助:)。这是我的python文件：

from kivy.app import App
from kivy.uix.textinput import TextInput
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.properties import NumericProperty,ListProperty,BooleanProperty,ObjectProperty,StringProperty
from kivy.uix.recycleview import RecycleView
from kivy.uix.recyclegridlayout import RecycleGridLayout
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.label import Label
from kivy.uix.recycleboxlayout import RecycleBoxLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior

class SelectableRecycleBoxLayout(FocusBehavior,LayoutSelectionBehavior,RecycleBoxLayout):
    ''' Adds selection and focus behaviour to the view. '''

class SelectableLabel(RecycleDataViewBehavior,Label):
    ''' Add selection support to the Label '''
    index = None
    selected = BooleanProperty(False)
    selectable = BooleanProperty(True)

    def refresh_view_attrs(self,rv,index,data):
        ''' Catch and handle the view changes '''
        self.index = index
        return super(SelectableLabel,self).refresh_view_attrs(
            rv,data)

    def on_touch_down(self,touch):
        ''' Add selection on touch down '''
        if super(SelectableLabel,self).on_touch_down(touch):
            return True
        if self.collide_point(*touch.pos) and self.selectable:
            self.parent.parent.parent.children[1].text = self.text # ajout test
            return self.parent.select_with_touch(self.index,touch)
        
    def apply_selection(self,is_selected):
        ''' Respond to the selection of items in the view. '''
        self.selected = is_selected
        if is_selected:
            print("selection changed to {0}".format(rv.data[index]))
    
class RV(RecycleView):
    def __init__(self,**kwargs):
        super(RV,self).__init__(**kwargs)

class DropDownWidget(BoxLayout):
    txt_input = ObjectProperty()
    rv = ObjectProperty()
    
class MyTextInput(TextInput):
    txt_input = ObjectProperty()
    flt_list = ObjectProperty()
    word_list = ListProperty()
    #this is the variable storing the number to which the look-up will start
    starting_no = NumericProperty(1)
    suggestion_text = ''

    def __init__(self,**kwargs):
        super(MyTextInput,self).__init__(**kwargs)
        
    def on_text(self,instance,value):
        #find all the occurrence of the word
        self.parent.ids.rv.data = []
        matches = [self.word_list[i] for i in range(len(self.word_list)) if self.word_list[i][:self.starting_no] == value[:self.starting_no]]
        
        #display the data in the recycleview
        display_data = []
        for i in matches:
            display_data.append({'text':i})
        self.parent.ids.rv.data = display_data
        
        #ensure the size is okay
        if len(matches) <= 10:
            self.parent.height = (50 + (len(matches)*20))
        else:
            self.parent.height = 240
        
    def keyboard_on_key_down(self,window,keycode,text,modifiers):
        if self.suggestion_text and keycode[1] == 'tab':
            self.insert_text(self.suggestion_text + ' ')
            return True
        return super(MyTextInput,self).keyboard_on_key_down(window,modifiers)

class Body(FloatLayout):
    def __init__(self,**kwargs):
        super(Body,self).__init__(**kwargs)
        self.add_widget(Label(text = 'This Label is hidden by the dropdown if you type in the text input : "row" or "example" \n and I would like the Text Input to be fixed and not going up when changing text',pos_hint = {'center_x':.5,'center_y':.6},color = [100,100,1]))
        widget_1 = DropDownWidget(pos_hint = {'center_x':.5,'center_y':.5},\
                               size_hint = (None,None),size = (600,60))
        widget_1.ids.txt_input.word_list = ['row1','row2','row3','row4','row5','line1','line2','example1','example2','example3','example4','example5','example6','example7','example8','example9','example10']
        self.add_widget(widget_1)
        
class MyApp(App):
    
    def build(self):
        return Body()

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

和我的kv文件：

<Body>:
    canvas:
        Color:
            rgba:(1,1,1) # white
        Rectangle:
            pos: self.pos
            size: self.size
            
<DropDownWidget>:
    canvas:
        Color:
            rgba:(1,1)
        Rectangle:
            pos: self.pos
            size: self.size
            
    orientation: 'vertical'
    spacing: 2
    txt_input: txt_input
    rv: rv

    MyTextInput:
        id: txt_input
        size_hint_y: None
        height: 50
        
    RV:
        id: rv
    
<MyTextInput>:
    readonly: False
    multiline: False

<SelectableLabel>:
    # Draw a background to indicate selection
    id: selabel
    color: 0,1
    canvas.before:
        Color:
            rgba: (0,.5) if self.selected else (1,1)
        Rectangle:
            pos: self.pos
            size: self.size
<RV>:
    canvas:
        Color:
            rgba: 0,.2

        Line:
            rectangle: self.x +1,self.y,self.width - 2,self.height -2
         
    bar_width: 10
    scroll_type:['bars']
    viewclass: 'SelectableLabel'
    SelectableRecycleBoxLayout:
        default_size: None,dp(20)
        default_size_hint: 1,None
        size_hint_y: None
        height: self.minimum_height
        orientation: 'vertical'
        multiselect: False

解决方法

实际上，当我运行您的代码时，看不到您描述的行为。但是，如果将Label和DropDownWidget添加到kv，则可以利用kv为您设置的绑定。这是我可能的操作方法（有很多选择）。首先，我在ListProperty上添加了DropDownWidget以容纳word_list：

class DropDownWidget(BoxLayout):
    txt_input = ObjectProperty()
    rv = ObjectProperty()
    word_list = ListProperty([])

Body类可以是：

class Body(FloatLayout):
    pass

然后，kv的开头可以是：

<Body>:
    canvas:
        Color:
            rgba:(1,1,1) # white
        Rectangle:
            pos: self.pos
            size: self.size
    Label:
        id: lab
        text: 'This Label is hidden by the dropdown if you type in the text input : "row" or "example"'
        pos_hint: {'center_x':.5,'center_y':.6}
        color: [100,100,1]
        size_hint: None,None
        size: self.texture_size  # use minimal size for the Label
    DropDownWidget:
        pos_hint: {'center_x':.5}
        y: lab.y - self.height  # position DropDownWidget just below the Label
        size_hint: None,None
        size: 600,60
        word_list: ['row1','row2','row3','row4','row5','line1','line2','example1','example2','example3','example4','example5','example6','example7','example8','example9','example10']
            
<DropDownWidget>:
    canvas:
        Color:
            rgba:(1,1)
        Rectangle:
            pos: self.pos
            size: self.size

    orientation: 'vertical'
    spacing: 2
    txt_input: txt_input
    rv: rv

    MyTextInput:
        id: txt_input
        size_hint_y: None
        height: 50
        word_list: root.word_list  # use the word_list from DropDownWidget
        
    RV:
        id: rv

kv的其余部分保持不变。