ios --- 动态获取键盘高度

需要手动调用 registerForKeyboardNotifications 方法，其他两个会自动调用，弹出的键盘高 216(输入英文时候)，ios 5 系统的

@implementation ViewController

- (void)viewDidLoad
{
[super viewDidLoad];
[self registerForKeyboardNotifications];
UITextView *tv = [[UITextView alloc] initWithFrame:CGRectMake(100, 100, 100, 50)];
[self.view addSubview:tv];
[tv release];
}
- (void) registerForKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasShown:) name:UIKeyboardDidShowNotification object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasHidden:) name:UIKeyboardDidHideNotification object:nil];
}

- (void) keyboardWasShown:(NSNotification *) notif
{
NSDictionary *info = [notif userInfo];
NSValue *value = [info objectForKey:UIKeyboardFrameBeginUserInfoKey];
CGSize keyboardSize = [value CGRectValue].size;

NSLog(@"keyBoard:%f", keyboardSize.height); //216
///keyboardWasShown = YES;
}
- (void) keyboardWasHidden:(NSNotification *) notif
{
NSDictionary *info = [notif userInfo];

NSValue *value = [info objectForKey:UIKeyboardFrameBeginUserInfoKey];
CGSize keyboardSize = [value CGRectValue].size;
NSLog(@"keyboardWasHidden keyBoard:%f", keyboardSize.height);
// keyboardWasShown = NO;

}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end