在constants.h文件中，你可以添加以下定义语句:

 #define IS_IPAD UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad 
 #define IS_IPHONE UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone
 #define IS_WIDESCREEN (fabs((double)[[UIScreen mainScreen] bounds].size.height - (double)568) < DBL_EPSILON) 
 #define IS_IPHONE_5 (!IS_IPAD && IS_WIDESCREEN)

通过xib .........很容易迁移iPhone5和iPhone4

UIViewController *viewController3;
if ([[UIScreen mainScreen] bounds].size.height == 568)
{
    UIViewController *viewController3 = [[[mainscreenview alloc] initWithNibName:@"iphone5screen" bundle:nil] autorelease];               
}    
else
{
     UIViewController *viewController3 = [[[mainscreenview alloc] initWithNibName:@"iphone4screen" bundle:nil] autorelease];
}

在这里你可以找到一个很好的教程(MonoTouch，但你也可以使用非MonoTouch项目的信息): http://redth.info/get-your-monotouch-apps-ready-for-iphone-5-ios-6-today/

为你的splash/default屏幕创建一个新图像(640 x 1136像素)，名称为Default-568h@2x.png 在iOS模拟器中，转到硬件->设备菜单，并选择“iPhone(视网膜4英寸)” 创建其他图像，例如背景图像 检测iPhone 5加载你的新图像:

public static bool IsTall
{
    get {
        return UIDevice.currentDevice.userInterfaceIdiom
                    == UIUserInterfaceIdiomPhone
                && UIScreen.mainScreen.bounds.size.height
                    * UIScreen.mainScreen.scale >= 1136;
    }
}

private static string tallMagic = "-568h@2x";
public static UIImage FromBundle16x9(string path)
{
    //adopt the -568h@2x naming convention
    if(IsTall())
    {
        var imagePath = Path.GetDirectoryName(path.ToString());
        var imageFile = Path.GetFileNameWithoutExtension(path.ToString());
        var imageExt = Path.GetExtension(path.ToString());
        imageFile = imageFile + tallMagic + imageExt;
        return UIImage.FromFile(Path.Combine(imagePath,imageFile));
    }
    else
    {
        return UIImage.FromBundle(path.ToString());
    }
}

Peter，你真的应该看看Canappi，它为你做了所有这些，你所要做的就是指定这样的布局:

button mySubmitButton 'Sumbit' (100,100,100,30 + 0,88,0,0) { ... }

从那里Canappi将生成正确的objective-c代码，检测应用程序正在运行的设备，并将使用:

(100,100,100,30) for iPhone4
(100,**188**,100,30) for iPhone 5

Canappi的工作原理类似于界面生成器和故事板的结合，除了它是文本形式。如果已经有XIB文件，可以转换它们，这样就不必从头重新创建整个UI。

你可以手动检查屏幕大小来确定你在哪个设备上:

#define DEVICE_IS_IPHONE5 ([[UIScreen mainScreen] bounds].size.height == 568)

float height = DEVICE_IS_IPHONE5?568:480;
if (height == 568) {
    // 4"

} else {

    // 3"

}

I never faced such an issue with any device as I've had one codebase for all, without any hardcoded values. What I do is to have the maximum sized image as resource instead of one for each device. For example, I would have one for retina display and show it as aspect fit so it will be views as is on every device. Coming to deciding the frame of button, for instance, at run time. For this I use the % value of the patent view, example , if I want the width to be half of parent view take 50 % of parent and same applies for height and center.

有了这个，我甚至不需要xib。