在 kivy 中滚动查看和清除小部件

Question

I'm new to Kivy and don't know everything yet. I've been struggling for days now to finish this little app that takes an xlsx file and uses it as a search base.

But my problem is that I don't know how to clear the results widget after pressing "Search" again and I am also trying to add scrolling for the search results. I simplified the program, but the principle remains the same. If you can tell me what I did wrong or how I should Google it.

   import kivy


    from kivy.app import App
    from kivy.uix.label import Label
    from kivy.uix.gridlayout import GridLayout
    from kivy.uix.textinput import TextInput
    from kivy.uix.button import Button

    from kivy.app import runTouchApp

    class MyGrid(GridLayout):
        def __init__(self, **kwargs):
            super(MyGrid, self).__init__(**kwargs)

            self.cols = 1

            self.inside  = GridLayout()
            self.inside.cols = 2

            self.inside.add_widget(Label(text="Label Name: "))
            self.label_name = TextInput(multiline=False)
            self.inside.add_widget(self.label_name)

            self.add_widget(self.inside)

            self.search = Button(text="Search", font_size=30)
            self.search.bind(on_press=self.pressed)
            self.add_widget(self.search)

            self.print = GridLayout()
            self.print.cols = 1
        
            self.add_widget(self.print)

        
       

    #Here a problem:

        def pressed(self, result):
            self.print.clear_widgets()
            # file = load_xlsx(self.label_name.text)
            for info in range(10):
                btn = Button(text=str(info), size_hint_y=None, height=40)
                self.print.add_widget(btn)
            
    class MyApp(App):
        def build(self):
            return MyGrid()

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

Answer 1

The example below allows you to clear widgets when you click the search button again, it is best to implement similar logic using RecycleView , because it dynamically loads content, which will allow you to display an almost unlimited number of widgets on the screen. When you enter a number in TextInput , the program will add widgets to the screen if they contain a digit passed in the input field. Tip, use .kv , it's convenient, and there is also syntax highlighting, use dp for dimensions - this is an abstract unit of measurement based on the physical density of the screen, allows you to keep the size of widgets the same on all screens and platforms.

from kivy.app import App
from kivy.lang.builder import Builder
from kivy.metrics import dp

KV = """
Screen:
    BoxLayout:
        orientation: 'vertical'
        
        BoxLayout:
            size_hint_y: None
            height: self.minimum_height
            
            Label:
                text: "Label Name: "
                
            TextInput:
                id: search_text
                multiline: False
                size_hint_y: None
                height: dp(50)
                
        Button:
            text: "Search"
            font_size: sp(30)
            pos_hint: {'center_x': 0.5}
            size_hint_y: None
            height: dp(50)
            on_release: app.pressed(search_text.text)
                
        RecycleView:
            id: rv_result
            key_size: "height"
            bar_width: dp(4)
            always_overscroll: False
            key_viewclass: "viewclass"
    
            RecycleGridLayout:
                id: result
                default_size_hint: 1, None
                size_hint_y: None
                height: self.minimum_height
                padding: dp(5)
                spacing: dp(7)
                cols: 1
                default_size: None, dp(48)
"""


class MyApp(App):
    def build(self):
        return Builder.load_string(KV)

    def pressed(self, result):
        if self.root.ids.rv_result.data:
            self.root.ids.rv_result.data = []
            self.root.ids.rv_result.refresh_from_layout()

        for info in range(100):
            info = str(info)

            if result in info:
                item = {
                    'viewclass': 'Button',
                    'text': info,
                    'size_hint_y': None,
                    'height': dp(40),
                }

                self.root.ids.rv_result.data.append(item)


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