IOS中检测键盘出现和消失的消息

IOS中键盘是在编辑控件获得第一响应者时出现，编辑控件有UITextField，UITextView等，这里以UITextField做为例子。

首先实现UITextFieldDelegate中的几个方法：

#pragma mark - UITextFieldDelegate


-(BOOL)textFieldShouldBeginEditing:(UITextField*)textField
{
   //注册键盘出现和消失的通知中心
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
    // 键盘高度变化通知，ios5.0新增的
#ifdef __IPHONE_5_0
    float version = [[[UIDevice currentDevice] systemVersion] floatValue];
    if (version >= 5.0) 
    {
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillChangeFrameNotification object:nil];
    }
#endif
	return YES;
}

-(void)textFieldDidEndEditing:(UITextField*)textField
{
#ifdef __IPHONE_5_0
    float version = [[[UIDevice currentDevice] systemVersion] floatValue];
    if (version >= 5.0) 
    {
        [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillChangeFrameNotification object:nil];
    }
#endif 
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

　　然后实现接收通知的方法：

　

- (void)keyboardWillShow:(NSNotification *)notification
{  
    NSDictionary *userInfo = [notification userInfo];
    NSValue* aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGRect keyboardRect = [aValue CGRectValue];
    NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
    [animationDurationValue getValue:&animationDuration];
	
	[UIView beginAnimations:nil context:nil];
	[UIView setAnimationDuration:animationDuration];
	//这里可以实现你想做的事情，比如聊天页面中聊天窗口的向上移动，以及编辑控件的移动等等。
	[UIView setAnimationDidStopSelector:@selector(animationStopForEndEditing)];
	[UIView setAnimationDelegate:self];
	
	[UIView commitAnimations];
}

- (void)keyboardWillHide:(NSNotification *)notification 
{    
    NSDictionary* userInfo = [notification userInfo];
    NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration;
    [animationDurationValue getValue:&animationDuration];
    
   	[UIView beginAnimations:nil context:nil];
	[UIView setAnimationDuration:animationDuration];
	//这里可以实现你想做的事情，比如聊天页面中聊天窗口的向上移动，以及编辑控件的移动等等。
	[UIView commitAnimations];
}