[ios] in iPhone App How to detect the screen resolution of the device

In iPhone App, while running the App on device How to detect the screen resolution of the device on which App is running?

For iOS 8 we can just use this [UIScreen mainScreen].nativeBounds , like that:

- (NSInteger)resolutionX
{
    return CGRectGetWidth([UIScreen mainScreen].nativeBounds);
}

- (NSInteger)resolutionY
{
    return CGRectGetHeight([UIScreen mainScreen].nativeBounds);
}

See the UIScreen Reference: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIScreen_Class/Reference/UIScreen.html

if([[UIScreen mainScreen] respondsToSelector:NSSelectorFromString(@"scale")])
{
    if ([[UIScreen mainScreen] scale] < 1.1)
        NSLog(@"Standard Resolution Device");

    if ([[UIScreen mainScreen] scale] > 1.9)
        NSLog(@"High Resolution Device");
}

Use this code it will help for getting any type of device's screen resolution

 [[UIScreen mainScreen] bounds].size.height
 [[UIScreen mainScreen] bounds].size.width

UIScreen class lets you find screen resolution in Points and Pixels.

Screen resolutions is measured in Points or Pixels. It should never be confused with screen size. A smaller screen size can have higher resolution.

UIScreen's 'bounds.width' return rectangular size in Points

UIScreen's 'nativeBounds.width' return rectangular size in Pixels.This value is detected as PPI ( Point per inch ). Shows the sharpness & clarity of the Image on a device.

You can use UIScreen class to detect all these values.

Swift3

// Normal Screen Bounds - Detect Screen size in Points.
let width = UIScreen.main.bounds.width
let height = UIScreen.main.bounds.height
print("\n width:\(width) \n height:\(height)")

// Native Bounds - Detect Screen size in Pixels.
let nWidth = UIScreen.main.nativeBounds.width
let nHeight = UIScreen.main.nativeBounds.height
print("\n Native Width:\(nWidth) \n Native Height:\(nHeight)")

Console

width:736.0 
height:414.0

Native Width:1080.0 
Native Height:1920.0

Swift 2.x

//Normal Bounds - Detect Screen size in Points.
    let width  = UIScreen.mainScreen.bounds.width
    let height = UIScreen.mainScreen.bounds.height

// Native Bounds - Detect Screen size in Pixels.
    let nWidth  = UIScreen.mainScreen.nativeBounds.width
    let nHeight = UIScreen.mainScreen.nativeBounds.height

ObjectiveC

// Normal Bounds - Detect Screen size in Points.
CGFloat *width  = [UIScreen mainScreen].bounds.size.width;
CGFloat *height = [UIScreen mainScreen].bounds.size.height;

// Native Bounds - Detect Screen size in Pixels.
CGFloat *width  = [UIScreen mainScreen].nativeBounds.size.width
CGFloat *height = [UIScreen mainScreen].nativeBounds.size.width

Use it in App Delegate: I am using storyboard

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

if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {

    CGSize iOSDeviceScreenSize = [[UIScreen mainScreen] bounds].size;

    //----------------HERE WE SETUP FOR IPHONE 4/4s/iPod----------------------

    if(iOSDeviceScreenSize.height == 480){          

        UIStoryboard *iPhone35Storyboard = [UIStoryboard storyboardWithName:@"iPhone" bundle:nil];

        // Instantiate the initial view controller object from the storyboard
        UIViewController *initialViewController = [iPhone35Storyboard instantiateInitialViewController];

        // Instantiate a UIWindow object and initialize it with the screen size of the iOS device
        self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

        // Set the initial view controller to be the root view controller of the window object
        self.window.rootViewController  = initialViewController;

        // Set the window object to be the key window and show it
        [self.window makeKeyAndVisible];

        iphone=@"4";

        NSLog(@"iPhone 4: %f", iOSDeviceScreenSize.height);

    }

    //----------------HERE WE SETUP FOR IPHONE 5----------------------

    if(iOSDeviceScreenSize.height == 568){

        // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone4
        UIStoryboard *iPhone4Storyboard = [UIStoryboard storyboardWithName:@"iPhone5" bundle:nil];

        // Instantiate the initial view controller object from the storyboard
        UIViewController *initialViewController = [iPhone4Storyboard instantiateInitialViewController];

        // Instantiate a UIWindow object and initialize it with the screen size of the iOS device
        self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

        // Set the initial view controller to be the root view controller of the window object
        self.window.rootViewController  = initialViewController;

        // Set the window object to be the key window and show it
        [self.window makeKeyAndVisible];

         NSLog(@"iPhone 5: %f", iOSDeviceScreenSize.height);
        iphone=@"5";
    }

} else if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
    // NSLog(@"wqweqe");
    storyboard = [UIStoryboard storyboardWithName:@"iPad" bundle:nil];

}

 return YES;
 }