【iPhoneXR,Xs,XsMaxの判別対応】Nativeコード内での判別方法（解像度での判別） ref: https://qiita.com/yoshiki-0428/items/30151967574791a02a0c

Device.m

#define ScreenHeight [UIScreen mainScreen].nativeBounds.size.height
#define ScreenWidth [UIScreen mainScreen].nativeBounds.size.width
#define ScreenScale [UIScreen mainScreen].scale

// iphoneX以上の端末を判別
+ (BOOL)isIphoneXOver {
    return (Device.isIphoneX || Device.isIphoneXs || Device.isIphoneXR || UIDevice.isIphoneXsMax);
}

+ (BOOL)isIphoneX {
    return [self checkIPhoneSize:1125.0 height:2436.0 scale:3.0];
}

+ (BOOL)isIphoneXs {
    return [self checkIPhoneSize:1125.0 height:2436.0 scale:3.0];
}

+ (BOOL)isIphoneXR {
    return [self checkIPhoneSize:828.0 height:1792.0 scale:2.0];
}

+ (BOOL)isIphoneXsMax {
    return [self checkIPhoneSize:1242.0 height:2688.0 scale:3.0];
}

+ (BOOL)checkIphoneSize:(CGFloat)width height:(CGFloat)height scale:(CGFloat)scale {
    static BOOL result = NO;
    if (@available(iOS 11.0, *)) {
        if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {
            result = ((ScreenWidth == width && ScreenHeight == height) && ScreenScale == scale);
        }
    }
    return result;
}