UIKeyboardWillShowNotification & UIKeyboardDidShowNotification report wrong keyboard height

Question

The following code (sorry for the length) displays an odd behavior under iOS 4.3 (maybe others version too). In this example, there are three UITextFields that have three different sized keyboards. If you start editing one text field and then touch "return" dismissing the keyboard, each time the keyboard size is returned correctly in UIKeyboardWillShowNotification and UIKeyboardDidShowNotification using UIKeyboardFrameBeginUserInfoKey.

see below:

- (void) keyboardWillShowNotification:(NSNotification *)aNotification

and

- (void) keyboardDidShowNotification:(NSNotification *)aNotification

Note that this is the expected behavior.

action                 reported keyboard size  expected keyboard size  
---------------------  ----------------------  ----------------------
touch one    & return  100                     100
touch two    & return  200                     200
touch normal & return  216                     216
n            & return  keyboard size(n)        keyboard size(n)

The unexpected behavior is if you start editing a text field the size of the first keyboard is reported (expected). When you touch the second text field (without touching return), the size of first keyboard is reported (unexpected) instead of the size of the second. When you touch the third text field (without touching return), the size of the second keyboard size is reported (unexpected) instead of the size of the third. For the second to nth times, it seems like it is reporting the previous keyboard's size not the one that will be displayed.

action        reported keyboard size  expected keyboard size  
------------  ----------------------  ----------------------
touch one     100                     100
touch two     100                     200
touch normal  200                     216
touch one     216                     100
n             keyboard size(n-1)      keyboard size(n)

Before I send in a bug report, I just want to make sure that I have not over looked anything.

FYI I stubbled upon this while trying to do the right thing (using UIKeyboardWillShowNotification or UIKeyboardDidShowNotification and UIKeyboardFrameBeginUserInfoKey to get the keyboard's size) when shifting a view so that a text field that would have been obscured by a keyboard is visible. Reference:

How to make a UITextField move up when keyboard is present?

iOS Library: Text, Web, and Editing Programming Guide for iOS --> Managing the Keyboard

iOS Library: Scroll View Programming Guide for iOS --> Creating and Configuring Scroll Views

BugVC.h

#import <UIKit/UIKit.h>

@interface BugVC : UIViewController <UITextFieldDelegate> {
    UITextField *oneTF;
    UITextField *twoTF;
    UITextField *normalTF;
    UILabel *keyboardWillShowNotificationL;
    UILabel *keyboardDidShowNotificationL;
}

- (void) oneReturnTouchDown:(id)sender;
- (void) twoReturnTouchDown:(id)sneder;
- (void) keyboardWillShowNotification:(NSNotification *)aNotification;
- (void) keyboardDidShowNotification:(NSNotification *)aNotification;

@end

BugVC.m

#import "BugVC.h"

@implementation BugVC

- (id) init
{
    if ( !(self = [super init]) )
    {
        return self;
    }

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // One text field with 100 height keyboard
    oneTF = [[UITextField alloc] initWithFrame:CGRectMake(10, 10, 300, 30)];
    oneTF.borderStyle = UITextBorderStyleRoundedRect;
    oneTF.text = @"100";
    oneTF.delegate = self;
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // Custom input view for the above text field
    UIView *oneInputView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
    oneInputView.backgroundColor = [UIColor redColor];
    UIButton *oneReturnB = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    oneReturnB.frame = CGRectMake(10, 10, 300, 30);
    [oneReturnB setTitle:@"return" forState:UIControlStateNormal];
    [oneReturnB addTarget:self
                   action:@selector(oneReturnTouchDown:)
         forControlEvents:UIControlEventTouchDown];
    [oneInputView addSubview:oneReturnB];
    oneTF.inputView = oneInputView;
    [oneInputView release];
    [self.view addSubview:oneTF];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Two text field with 200 height keyboard
    twoTF = [[UITextField alloc] initWithFrame:CGRectMake(10, 50, 300, 30)];
    twoTF.borderStyle = UITextBorderStyleRoundedRect;
    twoTF.text = @"200";
    twoTF.delegate = self;
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // Custom input view for the above text field
    UIView *twoInputView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 200)];
    twoInputView.backgroundColor = [UIColor blueColor];
    UIButton *twoReturnB = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    twoReturnB.frame = CGRectMake(10, 10, 300, 30);
    [twoReturnB setTitle:@"return" forState:UIControlStateNormal];
    [twoReturnB addTarget:self
                   action:@selector(twoReturnTouchDown:)
         forControlEvents:UIControlEventTouchDown];
    [twoInputView addSubview:twoReturnB];
    twoTF.inputView = twoInputView;
    [twoInputView release];
    [self.view addSubview:twoTF];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // normal text field with normal keyboard (216 height keyboard)
    normalTF = [[UITextField alloc] initWithFrame:CGRectMake(10, 90, 300, 30)];
    normalTF.borderStyle = UITextBorderStyleRoundedRect;
    normalTF.text = @"normal";
    normalTF.delegate = self;
    [self.view addSubview:normalTF];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Label that displays the keyboard height from keyboardWillShowNotification
    keyboardWillShowNotificationL = [[UILabel alloc] initWithFrame:CGRectMake(10, 130, 300, 30)];
    keyboardWillShowNotificationL.font = [UIFont systemFontOfSize:14];
    keyboardWillShowNotificationL.text = @"keyboardWillShowNotification kbHeight:";
    [self.view addSubview:keyboardWillShowNotificationL];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Label that displays the keyboard height from keyboardDidShowNotification
    keyboardDidShowNotificationL = [[UILabel alloc] initWithFrame:CGRectMake(10, 170, 300, 30)];
    keyboardDidShowNotificationL.font = [UIFont systemFontOfSize:14];
    keyboardDidShowNotificationL.text = @"keyboardDidShowNotification kbHeight:";
    [self.view addSubview:keyboardDidShowNotificationL];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Register for keyboard notifications.
    [[NSNotificationCenter defaultCenter]
     addObserver:self
        selector:@selector(keyboardWillShowNotification:)
            name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter]
     addObserver:self
        selector:@selector(keyboardDidShowNotification:)
            name:UIKeyboardDidShowNotification object:nil];

    return self;
}

- (void) dealloc
{
    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Deregister for keyboard notifications
    [[NSNotificationCenter defaultCenter]
     removeObserver:self
               name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter]
     removeObserver:self
               name:UIKeyboardDidShowNotification object:nil];

    [oneTF release];
    [twoTF release];
    [normalTF release];
    [keyboardWillShowNotificationL release];
    [keyboardDidShowNotificationL release];

    [super dealloc];
}

- (BOOL) textFieldShouldReturn:(UITextField *)textField
{
    [textField resignFirstResponder];

    return YES;
}

- (void) oneReturnTouchDown:(id)sender
{
    [oneTF.delegate textFieldShouldReturn:oneTF];
}

- (void) twoReturnTouchDown:(id)sneder
{
    [twoTF.delegate textFieldShouldReturn:twoTF];
}

- (void) keyboardWillShowNotification:(NSNotification *)aNotification
{
    NSDictionary *info = [aNotification userInfo];
    CGFloat kbHeight =
        [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;

    NSString *string = [[NSString alloc] initWithFormat:@"keyboardWillShowNotification kbHeight: %.2f", kbHeight];
    NSLog(@"%@", string);
    keyboardWillShowNotificationL.text = string;
    [string release];
}

- (void) keyboardDidShowNotification:(NSNotification *)aNotification
{
    NSDictionary *info = [aNotification userInfo];
    CGFloat kbHeight =
        [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;

    NSString *string = [[NSString alloc] initWithFormat:@"keyboardDidShowNotification kbHeight: %.2f", kbHeight];
    NSLog(@"%@", string);
    keyboardDidShowNotificationL.text = string;
    [string release];
}

@end

Answer 1

As reported in this question, the start frame (keyed by UIKeyboardFrameBeginUserInfoKey) is where the keyboard is at the beginning of the animation. UIKeyboardFrameEndUserInfoKey should get you the end frame instead. Presumably the size is also different between the frames.

Key reference: http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIWindow_Class/UIWindowClassReference/UIWindowClassReference.html#//apple_ref/doc/constant_group/Keyboard_Notification_User_Info_Keys