UIScreen MainScreen Bounds returning wrong size

问题

So I created a new project with the latest version of XCode and tried to log the screen size of my app (to determine the device type for UI). I ran the following code from my iPhone 5:

NSLog(@"%f", [[UIScreen mainScreen] bounds].size.height);

This returned 480, which is the screen size for the old iPhone family. I tried in the simulator and the same thing happened. Is there some property I have to enable in the project for it to recognize the screen size?

This only happens for 5+ devices; if I run the game on my iPad, it recognizes the 1024 screen size.

I know for a fact that this code has worked in the past. I made a game a while back using the exact same method and it had no problem detecting the screen size, but this was built in XCode 4.x.

Additional Info:

I am using a custom View Controller, which I create in the App Delegate with the following code:

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

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

    if([Global getDevice] == 1)
    {
        //iPhone 5+
        self.window.rootViewController = [[FivePlus alloc] initWithNibName:nil bundle:nil];

    }
    else if([Global getDevice] == 2)
    {
        //iPhone 4S-
        self.window.rootViewController = [[FourSMinus alloc] initWithNibName:nil bundle:nil];
    }
    else
    {
        //iPad
        self.window.rootViewController = [[iPad alloc] initWithNibName:nil bundle:nil];
    }

    [[self window] makeKeyAndVisible];

    // Override point for customization after application launch.
    return YES;
}

The getDevice method from Global.h:

+ (int)getDevice
{
if([[UIScreen mainScreen] bounds].size.height == 568 || [[UIScreen mainScreen] bounds].size.width == 568)
    {
        return 1;
    }
    else if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
    {
        return 3;
    }
    else
    {
        return 2;
    }
}

回答1:

Apparently, iOS relies solely on the presence of a launch image in the resolution of an iPhone 5+ in order to let the app run in that resolution.

There are two solutions to this problem:

1. Use Asset Catalogs

When you create a new project, there's this thing called an asset catalog which stores your launch image files. Add one of these to your project and presto!

2. Dig out some old files

If you've been around XCode for a while, you'll know that in one of the later versions of XCode 4.x, the app automatically created three default launch image files for your app called Default.png, Default@2x.png, and Default-568h@2x.png. You need these files in your app, which are essentially just black images with the resolutions 480x320, 960x640, and 1136x640, respectively (note that these are in HxW, not WxH).

Add these files to your "Supporting Files" group
Go to the project properties and select "Don't Use Asset Catalogs" from the Launch Image section
Delete the Asset Catalog.

Hopefully this helps someone else who encounters this ridiculous problem.

回答2:

iOS will often "pretend" what screen size you have. Apple assumes for example that if you don't have the right launch image for some resolution, then you haven't designed your app to work properly in that resolution, so it will run your app in a different size. In an extreme case, an iPhone only app running on an iPad will return 320 x 480.

As far as your application is concerned, the screen size reported is the screen size available to your application. If it reports 320 x 480 then that is what your application can use. Anything drawn below 480 pixels will not be visible.

You convince iOS to run your app in the resolution that you want for example by supplying a launch image in the right size. In the case of iPhone 6 and 6+, the user can run them in "Zoom" mode so they behave as if they had the screen of an iPhone 5 or 6 (just physically bigger).

回答3:

In XCode6 having no splash screen image for iPhone5 screen size will trigger a warning. XCode will add a default one (just plain black) if you press the warning.

This will enable the 'normal' simulator size.