How to get orientation-dependent height and width of the screen?

I'm trying to programmatically determine the current height and width of my application. I use this:

CGRect screenRect = [[UIScreen mainScreen] bounds];

But this yields a width of 320 and a height of 480, regardless of whether the device is in portrait or landscape orientation. How can I determine the current width and height (i.e. dependent upon the device orientation) of my main screen?

You can use something like UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation) to determine the orientation and then use the dimensions accordingly.

HOWEVER, during an orientation change like in UIViewController's

- (void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation 
                                 duration:(NSTimeInterval)duration

Use the orientation passed in toInterfaceOrientation since the UIApplication's statusBarOrientation will still point to the old orientation as it has not yet changed (since you're inside a will event handler).

Summary

There are several related posts to this, but each of them seem to indicate that you have to:

Look at [[UIScreen mainScreen] bounds] to get the dimensions,
Check what orientation you are in, and
Account for the status bar height (if shown)

Links

Iphone: Get current view dimensions or screen dimensions
IPhone/IPad: How to get screen width programmatically?
Objective C - how to get current screen resolution?
“Incorrect” frame / window size after re-orientation in iPhone or iPad
iPhone Dev SDK - get screen width

Working Code

I usually don't go this far, but you piqued my interest. The following code should do the trick. I wrote a Category on UIApplication. I added class methods for getting the currentSize or the size in a given orientation, which is what you would call in UIViewController's willRotateToInterfaceOrientation:duration:.

@interface UIApplication (AppDimensions)
+(CGSize) currentSize;
+(CGSize) sizeInOrientation:(UIInterfaceOrientation)orientation;
@end

@implementation UIApplication (AppDimensions)

+(CGSize) currentSize
{
    return [UIApplication sizeInOrientation:[UIApplication sharedApplication].statusBarOrientation];
}

+(CGSize) sizeInOrientation:(UIInterfaceOrientation)orientation
{
    CGSize size = [UIScreen mainScreen].bounds.size;
    UIApplication *application = [UIApplication sharedApplication];
    if (UIInterfaceOrientationIsLandscape(orientation))
    {
        size = CGSizeMake(size.height, size.width);
    }
    if (application.statusBarHidden == NO)
    {
        size.height -= MIN(application.statusBarFrame.size.width, application.statusBarFrame.size.height);
    }
    return size;
}

@end

To use the code simple call [UIApplication currentSize]. Also, I ran the above code, so I know it works and reports back the correct responses in all orientations. Note that I factor in the status bar. Interestingly I had to subtract the MIN of the status bar's height and width.

Hope this helps. :D

Other thoughts

You could go about getting the dimensions by looking at the UIWindow's rootViewController property. I've looked at this in the past and it similarly reports the same dimensions in both portrait and landscape except it reports having a rotate transform:

(gdb) po [[[[UIApplication sharedApplication] keyWindow] rootViewController] view]

<UILayoutContainerView: 0xf7296f0; frame = (0 0; 320 480); transform = [0, -1, 1, 0, 0, 0]; autoresize = W+H; layer = <CALayer: 0xf729b80>>

(gdb) po [[[[UIApplication sharedApplication] keyWindow] rootViewController] view]

<UILayoutContainerView: 0xf7296f0; frame = (0 0; 320 480); autoresize = W+H; layer = <CALayer: 0xf729b80>>

Not sure how your app works, but if you aren't using a navigation controller of some kind, you could have a UIView under your main view with the max height / width of parent and grows / shrinks with parent. Then you could do: [[[[[[[UIApplication sharedApplication] keyWindow] rootViewController] view] subviews] objectAtIndex:0] frame]. That looks pretty intense on one line, but you get the idea.

However... It would still be better to do the above 3 steps under the summary. Start messing with UIWindows and you'll find out weird stuff, like showing a UIAlertView will change UIApplication's keywindow to point at a new UIWindow that the UIAlertView created. Who knew? I did after finding a bug relying on keyWindow and discovering that it changed like that!

This is my solution code !This method can add to NSObject class's Categroy , or you can define a Top custom UIViewController class , and let all of your other UIViewControllers to inherit it .

-(CGRect)currentScreenBoundsDependOnOrientation
{  

    CGRect screenBounds = [UIScreen mainScreen].bounds ;
    CGFloat width = CGRectGetWidth(screenBounds)  ;
    CGFloat height = CGRectGetHeight(screenBounds) ;
    UIInterfaceOrientation interfaceOrientation = [UIApplication sharedApplication].statusBarOrientation;

    if(UIInterfaceOrientationIsPortrait(interfaceOrientation)){
        screenBounds.size = CGSizeMake(width, height);
    }else if(UIInterfaceOrientationIsLandscape(interfaceOrientation)){
        screenBounds.size = CGSizeMake(height, width);
    }
    return screenBounds ;
}

Note, after IOS8 , as Apple Document of UIScreen's bounds property says :

Discussion

This rectangle is specified in the current coordinate space, which takes into account any interface rotations in effect for the device. Therefore, the value of this property may change when the device rotates between portrait and landscape orientations.

so for the consideration of compatibility , we should detect the IOS version and make the change as below:

#define IsIOS8 (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_7_1)

-(CGRect)currentScreenBoundsDependOnOrientation
{  

    CGRect screenBounds = [UIScreen mainScreen].bounds ;
    if(IsIOS8){
        return screenBounds ;
    }
    CGFloat width = CGRectGetWidth(screenBounds)  ;
    CGFloat height = CGRectGetHeight(screenBounds) ;
    UIInterfaceOrientation interfaceOrientation = [UIApplication sharedApplication].statusBarOrientation;

    if(UIInterfaceOrientationIsPortrait(interfaceOrientation)){
        screenBounds.size = CGSizeMake(width, height);
    }else if(UIInterfaceOrientationIsLandscape(interfaceOrientation)){
        screenBounds.size = CGSizeMake(height, width);
    }
    return screenBounds ;
}

Here's a handy macro:

#define SCREEN_WIDTH (UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation) ? [[UIScreen mainScreen] bounds].size.width : [[UIScreen mainScreen] bounds].size.height)
#define SCREEN_HEIGHT (UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation) ? [[UIScreen mainScreen] bounds].size.height : [[UIScreen mainScreen] bounds].size.width)

In iOS 8+ you should use the viewWillTransitionToSize:withTransitionCoordinator method:

-(void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];

    // You can store size in an instance variable for later
    currentSize = size;

    // This is basically an animation block
    [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {

        // Get the new orientation if you want
        UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];

        // Adjust your views
        [self.myView setFrame:CGRectMake(0, 0, size.width, size.height)];

    } completion:^(id<UIViewControllerTransitionCoordinatorContext> context) {
        // Anything else you need to do at the end
    }];
}

This replaces the deprecated animation method that gave no information about size:

-(void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)orientation duration:(NSTimeInterval)duration

How to get orientation-dependent height and width of the screen?

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