55. FileChooser

If an application requires user data, we might display the FileChooser.

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Since this is an application, we need the App class. The root is based on BoxLayout. The root has one function, select(). This will be called from the kv file, when the user selects any file. If a filename has been passed to select(), it will pass it to the label. label is defined in the kv file and is an attribute.

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In the app class, we have to return the root class.

# ex55.py
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout

class Ex55(BoxLayout):
    def select(self, *args):
        try: self.label.text = args[1][0]
        except: pass

class Ex55App(App):
    def build(self):
        return Ex55()
    
if __name__ == '__main__':
    Ex55App().run()

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In the kv file, we define the outer BoxLayout to have a 'vertical' orientation, and then we start the inner BoxLayout.

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The inner BoxLayout has a default orientation of 'horizontal'. The first element is a FileChooserListView. We first set a background color. The on_selection is called, when the user selects a particular file, by clicking it. It will call the select() function.

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The next element in the Boxlayout is FileChooserIconView. We set a background color, and route the selected filename, to the select() function.

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Finally, we have a Label. It has an ID of label, which was used earlier in the attribute definition. It has a small size_hint in y direction as it will occupy a small portion of the screen at the bottom. We then set a background color.

# ex55.kv
<Ex55>:
    label: label
    orientation: 'vertical'
    BoxLayout:
        FileChooserListView:
            canvas.before:
                Color:
                    rgb: .4,.5,.5
                Rectangle:
                    pos: self.pos
                    size: self.size
            on_selection: root.select(*args)
        FileChooserIconView:
            canvas.before:
                Color:
                    rgb: .5,.4,.5
                Rectangle:
                    pos: self.pos
                    size: self.size
            on_selection: root.select(*args)
    Label:
        id: label
        size_hint_y: .1
        canvas.before:
            Color:
                rgb: .5,.5,.4
            Rectangle:
                pos: self.pos
                size: self.size
        

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In the result, we can see the two FileChooser views, on the top-left, and top-right, which together, are about 90% of the screen area. These have different background colors, set in the kv file. The label on the bottom, indicates currently selected file.

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