gistfile1.py

#:kivy 1.0.9                                                                                                                                                   
TestWidget:

<RectangleWidget@Widget>:
    source: ''
    canvas:
	Color:
            rgba: 1, 1, 1, 1
        Rectangle:
            pos: self.pos
            size: self.size
            source: root.source

<TestWidget>:
    orientation: 'vertical'

    BoxLayout:
	orientation: 'horizontal'  # This is actually the default                                                                                              
	size_hint_y: None
	height: 88

        RectangleWidget:
        RectangleWidget:
            size_hint_x: None
            width: 160
            source: 'logo-slim.png'
        RectangleWidget:
            size_hint_x: None
            width: 35
    GridLayout:
        cols: 2
        rows: 10
        pos: 0, 114
        size: root.width, root.height-114-88
        Button:
            text: "Check"
            font_size: 14
            #pos: 50, 27                                                                                                                                       
            size: 75, 55
            id: checkbutton
            on_press: app.chk_btn_callback(self)

        Label:
            #font_size: 14                                                                                                                                     
            #pos: checkbutton.center_x, checkbutton.center_y                                                                                                   
            size: 75, 55
            text: "Disconnected"

        Button:
            text: "Text"
        Label:
            text: "Abc"

    BoxLayout:
        orientation: 'horizontal'
	size_hint_y: None
	height: 88
        Widget:  # I'm using this just as a spacer, since you have nothing here                                                                                
        RectangleWidget:
            size_hint_x: None
            width: 425