According to me the best way of dealing with such problems and avoiding couple of condition required for checking the the height of device, is using the relative frame for views or any UI element which you are adding to you view for example: if you are adding some UI element which you want should at the bottom of view or just above tab bar then you should take the y origin with respect to your view's height or with respect to tab bar (if present) and we have auto resizing property as well. I hope this will work for you

使用xCode 5，在项目>General上选择“迁移到资产目录”。

然后使用“Show in finder”找到你的启动图像，你可以模拟编辑它为640x1136，然后拖到资产目录，如下图所示。

确保iOS7和iOS6 R4部分都有一个640x1136的图像。下次你启动应用程序时，黑条将消失，你的应用程序将使用4英寸的屏幕

首先，创建两个xib并将所有委托，main类附加到xib，然后你可以在你的appdelegate中放入下面提到的条件。M文件在

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 

    if ([[UIScreen mainScreen] bounds].size.height == 568)
        {

        self.ViewController = [[ViewController alloc] initWithNibName:@"ViewControlleriphone5" bundle:nil];
        }

        else
        {
             self.ViewController = [[ViewController alloc] initWithNibName:@"ViewControlleriphone4" bundle:nil];

        }

你可以在程序的任何地方使用它，这取决于你的需求，甚至在你的ViewController类中。最重要的是，您已经为iphone 4(320*480)和iphone 5(320*568)分别创建了两个xib文件。

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。

我解决了这个问题。只需要在图像中添加~568h@2x后缀，在xib的图像中添加~568h。不需要更多的运行时检查或代码更改。

你可以添加以下代码:

if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone){
        if ([[UIScreen mainScreen] respondsToSelector: @selector(scale)]) {
            CGSize result = [[UIScreen mainScreen] bounds].size;
            CGFloat scale = [UIScreen mainScreen].scale;
            result = CGSizeMake(result.width * scale, result.height * scale);

            if(result.height == 960) {
                NSLog(@"iPhone 4 Resolution");
            }
            if(result.height == 1136) {
              NSLog(@"iPhone 5 Resolution");
            }
        }
        else{
            NSLog(@"Standard Resolution");
        }
    }