This solution is based on ComSubVie’s one.
Advantages:
- It supports device rotation – works for all orientations;
- It doesn’t hardcode the values for animation duration and curve, it reads them from the keyboard notification;
- It utilizes
UIKeyboardWillShowNotification
instead ofUIKeyboardDidShowNotification
to sync keyboard animation and custom actions; - It doesn’t use the deprecated
UIKeyboardBoundsUserInfoKey
; - It handles keyboard resize due to pressing the International key;
- Fixed memory leak by unregistering for keyboard events;
- All keyboard handling code is encapsulated in a separate class –
KBKeyboardHandler
; - Flexibility –
KBKeyboardHandler
class may be easy extended / modified to better suit specific needs;
Limitations:
- Works for iOS 4 and above, it needs small modifications to support older versions;
- It works for applications with a single
UIWindow
. If you use multiple UIWindows, you may need to modifyretrieveFrameFromNotification:
method.
Usage:
Include KBKeyboardHandler.h, KBKeyboardHandler.m and KBKeyboardHandlerDelegate.h in your project. Implement the KBKeyboardHandlerDelegate
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 KBKeyboardHandler
and set its delegate (typically self). See sample MyViewController
below.
KBKeyboardHandler.h:
#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
KBKeyboardHandler.m:
#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
KBKeyboardHandlerDelegate.h:
@protocol KBKeyboardHandlerDelegate
- (void)keyboardSizeChanged:(CGSize)delta;
@end
Sample MyViewController.h:
@interface MyViewController : UIViewController<KBKeyboardHandlerDelegate>
...
@end
Sample MyViewController.m:
@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;
}
UPDATE: Fixed iOS 7 warning, thanks @weienv.