以下代码（很抱歉长度较长）在iOS 4.3（或其他版本）下表现出奇怪的行为。在这个例子中，有三个UITextField，具有三种不同大小的键盘。如果你开始编辑一个文本框，然后点击“return”关闭键盘，每次键盘大小在UIKeyboardWillShowNotification和UIKeyboardDidShowNotification中会正确地返回，使用UIKeyboardFrameBeginUserInfoKey。
请参见下面：
- (void) keyboardWillShowNotification:(NSNotification *)aNotification
和
- (void) keyboardDidShowNotification:(NSNotification *)aNotification
请注意，这是预期的行为。
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)
如果您开始编辑一个文本字段，将报告第一个键盘的大小（预期的行为），但是当您触摸第二个文本字段（不点击返回键）时，会报告第一个键盘的大小（意外的行为），而不是第二个键盘的大小。当您触摸第三个文本字段（不点击返回键）时，会报告第二个键盘的大小（意外的行为），而不是第三个键盘的大小。对于第二次到第n次，似乎会报告先前键盘的大小，而不是将要显示的键盘的大小。
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)
在提交错误报告之前，我只想确保我没有忽略任何东西。
顺便提一下，我在尝试通过使用 UIKeyboardWillShowNotification 或 UIKeyboardDidShowNotification 以及 UIKeyboardFrameBeginUserInfoKey 来获取键盘大小来移动视图，以使被键盘遮挡的文本字段可见。 参考文献：
iOS库：iOS 的文本、 Web 和编辑编程指南-->管理键盘
iOS库：iOS 的滚动视图编程指南-->创建和配置滚动视图
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