Make stuff stick to the top or bottom of the screen in Corona SDK.

CoronaStickToTopAndBottom.lua

-- Putting a rectangle at the bottom of the screen and having it expand
-- all the way across the screen, like a status bar.
-- Important to note: I'm using "Letterbox" mode in my config.lua
local actualBottomY = display.contentHeight - display.screenOriginY
local actualTopY = display.screenOriginY
local deviceWidth = ( display.contentWidth - (display.screenOriginX * 2) ) / display.contentScaleX
local scaleFactor = deviceWidth / display.actualContentWidth
local actualWidth = (deviceWidth / scaleFactor)
local actualLeftX = (display.contentWidth - actualWidth) * .5

print ("screenOriginY:", display.screenOriginY)
print ("actualBottomY:", actualBottomY)
print ("actualTopY:", actualTopY)
print ("deviceWidth:", deviceWidth)
print ("scaleFactor:", scaleFactor )
print ("actualWidth:", actualWidth)
print ("actualContentWidth:", display.actualContentWidth)
print ("actualLeftX:", actualLeftX)


local topRect = display.newRect( 0, 0, actualWidth, 40)
topRect.anchorX = .5
topRect.anchorY = 0
topRect.x = halfW
topRect.y = actualTopY
topRect:setFillColor( 0, 0, 1)
topRect.strokeWidth = 2
topRect:setStrokeColor( 1 )
group:insert (topRect)

local bottomRect = display.newRect( 0, 0, actualWidth, 40)
bottomRect.anchorX = .5
bottomRect.anchorY = 1
bottomRect.x = halfW
bottomRect.y = actualBottomY
bottomRect:setFillColor( 1, 0, 0)
bottomRect.strokeWidth = 2
bottomRect:setStrokeColor( 1 )
group:insert (bottomRect)