Developing same UI for 3.5, 4.0 (updated 4.7 and 5.5) inches screens in Xcode 5.0.1 (updated xcode 6), no landscape, no iPad and no storyboard

Question

1. I have developed app considering 3.5 inch with .xib files and not storyboard.
2. I am unable to find any tutorial or guide which will help me in designing app si

Answer 1

SWIFT:

if(DeviceType.IS_IPHONE_4_OR_LESS)
{
//DO THIS 
}
//*********************************************************************
    enum UIUserInterfaceIdiom : Int
    {
        case Unspecified
        case Phone
        case Pad
    }

    struct ScreenSize
    {
        static let SCREEN_WIDTH         = UIScreen.mainScreen().bounds.size.width
        static let SCREEN_HEIGHT        = UIScreen.mainScreen().bounds.size.height
        static let SCREEN_MAX_LENGTH    = max(ScreenSize.SCREEN_WIDTH, ScreenSize.SCREEN_HEIGHT)
        static let SCREEN_MIN_LENGTH    = min(ScreenSize.SCREEN_WIDTH, ScreenSize.SCREEN_HEIGHT)
    }

    struct DeviceType
    {
        static let IS_IPHONE_4_OR_LESS  = UIDevice.currentDevice().userInterfaceIdiom == .Phone && ScreenSize.SCREEN_MAX_LENGTH < 568.0
        static let IS_IPHONE_5          = UIDevice.currentDevice().userInterfaceIdiom == .Phone && ScreenSize.SCREEN_MAX_LENGTH == 568.0
        static let IS_IPHONE_6          = UIDevice.currentDevice().userInterfaceIdiom == .Phone && ScreenSize.SCREEN_MAX_LENGTH == 667.0
        static let IS_IPHONE_6P         = UIDevice.currentDevice().userInterfaceIdiom == .Phone && ScreenSize.SCREEN_MAX_LENGTH == 736.0
        static let IS_IPAD              = UIDevice.currentDevice().userInterfaceIdiom == .Pad && ScreenSize.SCREEN_MAX_LENGTH == 1024.0
    }