下面的代码（对不起，长度）在 iOS 4.3（也许其他版本）下显示了一个奇怪的行为。在此示例中，有 3 个UITextFields 具有三个不同大小的键盘。如果您开始编辑一个文本字段，然后触摸“返回”关闭键盘，则UIKeyboardWillShowNotification每次UIKeyboardDidShowNotification使用UIKeyboardFrameBeginUserInfoKey.
见下文：
- (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)
意外行为是，如果您开始编辑文本字段，则会报告（预期）第一个键盘的大小。当您触摸第二个文本字段（不触摸返回）时，将报告（意外）第一个键盘的大小而不是第二个键盘的大小。当您触摸第三个文本字段（不触摸返回）时，将报告（意外）第二个键盘大小的大小，而不是第三个的大小。第二次到第 n 次，它似乎在报告前一个键盘的大小，而不是将显示的大小。
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)
在我发送错误报告之前，我只是想确保我没有过度查看任何内容。
仅供参考，在移动视图时尝试做正确的事情（使用UIKeyboardWillShowNotification或获取键盘的大小）时，我发现了这一点UIKeyboardDidShowNotification，UIKeyboardFrameBeginUserInfoKey以便可以看到本应被键盘遮挡的文本字段。参考：
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
错误VC.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
错误VC.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