customwidget.kv

'''
<CustButton@Button>:
    font_size : 32
    color: 0, 0, 0, 1
    size: 150, 50
    background_normal:''
    background_down:'disk.png'
    background_color:.88, .88, .88, 1

<CustomWidget>:
    CustButton:
        text: "Random"
        pos: root.x, 200

    CustButton:
        text: "Random"
        pos: 200, root.y

    CustButton:
        text: "Buttons"
        pos: 200, 400
'''


<CustButton@Button>:
    font_size : 32
    color: 0, 0, 0, 1
    size: 150, 50
    background_normal:''
    background_down:'disk.png'
    background_color:.88, .88, .88, 1
    size_hint: .4, .3

<FloatLayout>:
    CustButton:
        text: "Top Left"
        pos_hint: {"x":0, "top": 1}

    CustButton:
        text: "Bottom Left"
        pos_hint: {"right":1, "y": 0}

    CustButton:
        text: "Top Right"
        pos_hint: {"right":1, "top": 1}

    CustButton:
        text: "Bottom Left"
        pos_hint: {"left":1, "bottom": 0}

    CustButton:
        text: "Center"
        pos_hint: {"center_x":.5, "center": .5}