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copied!<p>This solution is based on ComSubVie's one.</p> <p>Advantages:</p> <ul> <li>It supports device rotation - works for all orientations;</li> <li>It doesn't hardcode the values for animation duration and curve, it reads them from the keyboard notification;</li> <li>It utilizes <code>UIKeyboardWillShowNotification</code> instead of <code>UIKeyboardDidShowNotification</code> to sync keyboard animation and custom actions;</li> <li>It doesn't use the deprecated <code>UIKeyboardBoundsUserInfoKey</code>;</li> <li>It handles keyboard resize due to pressing the International key;</li> <li>Fixed memory leak by unregistering for keyboard events;</li> <li>All keyboard handling code is encapsulated in a separate class - <code>KBKeyboardHandler</code>;</li> <li>Flexibility - <code>KBKeyboardHandler</code> class may be easy extended / modified to better suit specific needs;</li> </ul> <p>Limitations:</p> <ul> <li>Works for iOS 4 and above, it needs small modifications to support older versions;</li> <li>It works for applications with a single <code>UIWindow</code>. If you use multiple UIWindows, you may need to modify <code>retrieveFrameFromNotification:</code> method.</li> </ul> <p>Usage:</p> <p>Include KBKeyboardHandler.h, KBKeyboardHandler.m and KBKeyboardHandlerDelegate.h in your project. Implement the <code>KBKeyboardHandlerDelegate</code> protocol in your view controller - it consists of a single method, which will be called when keyboard is shown, hidden or its size is changed. Instantiate the <code>KBKeyboardHandler</code> and set its delegate (typically self). See sample <code>MyViewController</code> below.</p> <p><strong>KBKeyboardHandler.h</strong>:</p> <pre><code>#import <Foundation/Foundation.h> #import <UIKit/UIKit.h> @protocol KBKeyboardHandlerDelegate; @interface KBKeyboardHandler : NSObject - (id)init; // Put 'weak' instead of 'assign' if you use ARC @property(nonatomic, assign) id<KBKeyboardHandlerDelegate> delegate; @property(nonatomic) CGRect frame; @end </code></pre> <p><strong>KBKeyboardHandler.m</strong>:</p> <pre><code>#import "KBKeyboardHandler.h" #import "KBKeyboardHandlerDelegate.h" @implementation KBKeyboardHandler - (id)init { self = [super init]; if (self) { [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil]; } return self; } - (void)dealloc { [[NSNotificationCenter defaultCenter] removeObserver:self]; [super dealloc]; } @synthesize delegate; @synthesize frame; - (void)keyboardWillShow:(NSNotification *)notification { CGRect oldFrame = self.frame; [self retrieveFrameFromNotification:notification]; if (oldFrame.size.height != self.frame.size.height) { CGSize delta = CGSizeMake(self.frame.size.width - oldFrame.size.width, self.frame.size.height - oldFrame.size.height); if (self.delegate) [self notifySizeChanged:delta notification:notification]; } } - (void)keyboardWillHide:(NSNotification *)notification { if (self.frame.size.height > 0.0) { [self retrieveFrameFromNotification:notification]; CGSize delta = CGSizeMake(-self.frame.size.width, -self.frame.size.height); if (self.delegate) [self notifySizeChanged:delta notification:notification]; } self.frame = CGRectZero; } - (void)retrieveFrameFromNotification:(NSNotification *)notification { CGRect keyboardRect; [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardRect]; self.frame = [[UIApplication sharedApplication].keyWindow.rootViewController.view convertRect:keyboardRect fromView:nil]; } - (void)notifySizeChanged:(CGSize)delta notification:(NSNotification *)notification { NSDictionary *info = [notification userInfo]; UIViewAnimationOptions curve; [[info objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&curve]; NSTimeInterval duration; [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&duration]; void (^action)(void) = ^{ [self.delegate keyboardSizeChanged:delta]; }; [UIView animateWithDuration:duration delay:0.0 options:curve animations:action completion:nil]; } @end </code></pre> <p><strong>KBKeyboardHandlerDelegate.h</strong>:</p> <pre><code>@protocol KBKeyboardHandlerDelegate - (void)keyboardSizeChanged:(CGSize)delta; @end </code></pre> <p>Sample <strong>MyViewController.h</strong>:</p> <pre><code>@interface MyViewController : UIViewController<KBKeyboardHandlerDelegate> ... @end </code></pre> <p>Sample <strong>MyViewController.m</strong>:</p> <pre><code>@implementation MyViewController { KBKeyboardHandler *keyboard; } - (void)dealloc { keyboard.delegate = nil; [keyboard release]; [super dealloc]; } - (void)viewDidLoad { [super viewDidLoad]; keyboard = [[KBKeyboardHandler alloc] init]; keyboard.delegate = self; } - (void)viewDidUnload { [super viewDidUnload]; keyboard.delegate = nil; [keyboard release]; keyboard = nil; } - (void)keyboardSizeChanged:(CGSize)delta { // Resize / reposition your views here. All actions performed here // will appear animated. // delta is the difference between the previous size of the keyboard // and the new one. // For instance when the keyboard is shown, // delta may has width=768, height=264, // when the keyboard is hidden: width=-768, height=-264. // Use keyboard.frame.size to get the real keyboard size. // Sample: CGRect frame = self.view.frame; frame.size.height -= delta.height; self.view.frame = frame; } </code></pre> <p>UPDATE: Fixed iOS 7 warning, thanks @weienv.</p>

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