在Swift 4.2和Xcode 10中

if UIDevice().userInterfaceIdiom == .phone {
    //This is iPhone
} else if UIDevice().userInterfaceIdiom == .pad { 
    //This is iPad
} else if UIDevice().userInterfaceIdiom == .tv {
    //This is Apple TV
}

如果你想检测特定的设备

let screenHeight = UIScreen.main.bounds.size.height
if UIDevice().userInterfaceIdiom == .phone {
    if (screenHeight >= 667) {
        print("iPhone 6 and later")
    } else if (screenHeight == 568) {
        print("SE, 5C, 5S")
    } else if(screenHeight<=480){
        print("4S")
    }
} else if UIDevice().userInterfaceIdiom == .pad { 
    //This is iPad
}

if(UI_USER_INTERFACE_IDIOM () == UIUserInterfaceIdiom.pad)
 {
            print("This is iPad")
 }else if (UI_USER_INTERFACE_IDIOM () == UIUserInterfaceIdiom.phone)
 {
            print("This is iPhone");
  }

UI_USER_INTERFACE_IDIOM()只返回iPad如果应用程序是iPad或通用。如果这是一款运行在iPad上的iPhone应用，那么它就不会这么做。所以你应该检查模型。

在Swift中有很多方法可以做到这一点:

我们检查下面的模型(这里我们只能进行区分大小写的搜索):

class func isUserUsingAnIpad() -> Bool {
    let deviceModel = UIDevice.currentDevice().model
    let result: Bool = NSString(string: deviceModel).containsString("iPad")
    return result
}

我们检查下面的模型(我们可以在这里进行区分大小写的搜索):

    class func isUserUsingAnIpad() -> Bool {
        let deviceModel = UIDevice.currentDevice().model
        let deviceModelNumberOfCharacters: Int = count(deviceModel)
        if deviceModel.rangeOfString("iPad",
                                     options: NSStringCompareOptions.LiteralSearch,
                                     range: Range<String.Index>(start: deviceModel.startIndex,
                                                                end: advance(deviceModel.startIndex, deviceModelNumberOfCharacters)),
                                     locale: nil) != nil {
            return true
        } else {
            return false
        }
   }

UIDevice.currentDevice()。下面的userInterfaceIdiom只返回iPad，如果应用程序是iPad或Universal。如果这是一款在iPad上运行的iPhone应用，那么它就不会这么做。所以你应该检查模型。：

    class func isUserUsingAnIpad() -> Bool {
        if UIDevice.currentDevice().userInterfaceIdiom == UIUserInterfaceIdiom.Pad {
            return true
        } else {
            return false
        }
   }

如果类没有继承UIViewController，下面的代码段不会编译，否则它就可以正常工作。无论如何，UI_USER_INTERFACE_IDIOM()只返回iPad，如果应用程序是iPad或通用。如果这是一款在iPad上运行的iPhone应用，那么它就不会这么做。所以你应该检查模型。：

class func isUserUsingAnIpad() -> Bool {
    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiom.Pad) {
        return true
    } else {
        return false
    }
}

在Swift 4.2和Xcode 10中

if UIDevice().userInterfaceIdiom == .phone {
    //This is iPhone
} else if UIDevice().userInterfaceIdiom == .pad { 
    //This is iPad
} else if UIDevice().userInterfaceIdiom == .tv {
    //This is Apple TV
}

如果你想检测特定的设备

let screenHeight = UIScreen.main.bounds.size.height
if UIDevice().userInterfaceIdiom == .phone {
    if (screenHeight >= 667) {
        print("iPhone 6 and later")
    } else if (screenHeight == 568) {
        print("SE, 5C, 5S")
    } else if(screenHeight<=480){
        print("4S")
    }
} else if UIDevice().userInterfaceIdiom == .pad { 
    //This is iPad
}

*

在swift 3.0中

*

 if UIDevice.current.userInterfaceIdiom == .pad {
        //pad
    } else if UIDevice.current.userInterfaceIdiom == .phone {
        //phone
    } else if UIDevice.current.userInterfaceIdiom == .tv {
        //tv
    } else if UIDevice.current.userInterfaceIdiom == .carPlay {
        //CarDisplay
    } else {
        //unspecified
    }