iPhone 6 / iPhone 6+ launch screen size issue - ios

Question

I want to optimize my app for iPhone 6 and iPhone 6+
But I have a launch screen size problem.
I created a simple project, and AppDelegate's code is:
#import "AppDelegate.h"
#import "ViewControllerOne.h" //xib screen size is 4 inch.
#import "ViewControllerTwo.h" // xib screen size is 4.7 inch.
#import "ViewControllerThree.h" // xib screen size is 5.5 inch.
#implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {
if ([UIScreen mainScreen].bounds.size.height == 568.0) {//4 inch
ViewControllerOne *first = [[ViewControllerOne alloc]init];
UINavigationController *navigation = [[UINavigationController alloc]initWithRootViewController:first];
self.window.rootViewController = navigation;
}
else if ([UIScreen mainScreen].bounds.size.height == 667.0){//4.7inch
ViewControllerTwo * second = [[ViewControllerTwo alloc]init];
UINavigationController *navigation = [[UINavigationController alloc]initWithRootViewController:second];
self.window.rootViewController = navigation;
}
else if ([UIScreen mainScreen].bounds.size.height == 736.0){//5.5inch
ViewControllerThree *third = [[ViewControllerThree alloc]init];
UINavigationController *navigation = [[UINavigationController alloc]initWithRootViewController:third];
self.window.rootViewController = navigation;
}
}
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
#end
When I run iPhone 6 or iPhone 6+ simulator, it always appears 4inch screen when I run this project.(I included three launch image(Default-667h#2x.png, Default-736#3x.png, Default-568#2x.png) also.
What I have to do to resolve this problem.
I checked others question that similar to mine, and used their code, but all of those not works. That is maybe my technical skills relatively row.

Answer 1

Once you specify the images in Assets Catalog you will see the right images
Go to YourAppTarget> General> App Icons and Launch Images> Launch Image Source > Use asset Catalog
and then drag the appropriate size for each device.

Answer 2

In addition to adding images you can also add a Launch Screen File. This is a .XIB file that allows you to specify constraints in addition of launch images. It only works on iOS8. To support iPhone 6 and 6+, we only add this file and specify constraints:
To set the Launch Screen File add it to your project:
File > New > User Interface > Launch Screen
Then go to: YourAppTarget > General > App Icons and Launch Image s> Launch Screen File > Set your newly created image
You will still need launch images for Retina 4" and 3.5", if you are supporting iOS 7.