如何得到与方向相关的屏幕高度和宽度？

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:

1. Look at [[UIScreen mainScreen] bounds] to get the dimensions,
2. Check what orientation you are in, and
3. 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)

if you want the orientation dependent size and you have a view, you can just use:

view.bounds.size

As of iOS 8 screen bounds are now returned correct for current orientation. This means an iPad in landscape orientation [UIScreen mainScreen].bounds would return 768 on iOS <=7 and 1024 on iOS 8.

The following returns the correct height and width on all versions released.

-(CGRect)currentScreenBoundsDependOnOrientation
{
NSString *reqSysVer = @"8.0";
NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
if ([currSysVer compare:reqSysVer options:NSNumericSearch] != NSOrderedAscending)
return [UIScreen mainScreen].bounds;


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);
NSLog(@"Portrait Height: %f", screenBounds.size.height);
}else if(UIInterfaceOrientationIsLandscape(interfaceOrientation)){
screenBounds.size = CGSizeMake(height, width);
NSLog(@"Landscape Height: %f", screenBounds.size.height);
}


return screenBounds ;
}

float msWidth = [[UIScreen mainScreen] bounds].size.width*(IS_RETINA?2.0f:1.0f);
float msHeight = [[UIScreen mainScreen] bounds].size.height*(IS_RETINA?2.0f:1.0f);
if ( UIInterfaceOrientationIsPortrait(self.interfaceOrientation) ) {
os->setWidth(MIN(msWidth, msHeight));
os->setHeight(MAX(msWidth, msHeight));
} else {
os->setWidth(MAX(msWidth, msHeight));
os->setHeight(MIN(msWidth, msHeight));
}


NSLog(@"screen_w %f", os->getWidth());
NSLog(@"screen_h %f", os->getHeight());

However, on iOS 8.0.2:

+ (NSUInteger)currentWindowWidth
{
NSInteger width = 0;
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
CGSize size = [UIScreen mainScreen].bounds.size;
// if (UIInterfaceOrientationIsLandscape(orientation)) {
//     width = size.height;
// } else {
width = size.width;
//  }


return width;
}

I wrote category for UIScreen, that works on all iOS versions, so you can use it like this:
[[UIScreen mainScreen] currentScreenSize].

@implementation UIScreen (ScreenSize)


- (CGSize)currentScreenSize {
CGRect screenBounds = [[UIScreen mainScreen] bounds];
CGSize screenSize = screenBounds.size;


if ( NSFoundationVersionNumber <= NSFoundationVersionNumber_iOS_7_1 ) {
UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];
if ( UIInterfaceOrientationIsLandscape(interfaceOrientation) ) {
screenSize = CGSizeMake(screenSize.height, screenSize.width);
}
}


return screenSize;
}


@end

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

Here is a Swift way to get orientation dependent screen sizes:

var screenWidth: CGFloat {
if UIInterfaceOrientationIsPortrait(screenOrientation) {
return UIScreen.mainScreen().bounds.size.width
} else {
return UIScreen.mainScreen().bounds.size.height
}
}
var screenHeight: CGFloat {
if UIInterfaceOrientationIsPortrait(screenOrientation) {
return UIScreen.mainScreen().bounds.size.height
} else {
return UIScreen.mainScreen().bounds.size.width
}
}
var screenOrientation: UIInterfaceOrientation {
return UIApplication.sharedApplication().statusBarOrientation
}

These are included as a standard function in a project of mine:

https://github.com/goktugyil/EZSwiftExtensions

use -> setNeedsDisplay() for the view you want to resize.

Some improvements on the answers offered here, in Swift:

    let interfaceOrientation = UIApplication.shared.statusBarOrientation // (< iOS 13)
let screenSize = UIScreen.main.bounds.size
let screenWidth = interfaceOrientation.isPortrait ? screenSize.width : screenSize.height
let screenHeight = interfaceOrientation.isPortrait ? screenSize.height : screenSize.width