监听键盘的事件

//监听键盘出现和消失
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

#pragma mark 键盘出现
-(void)keyboardWillShow:(NSNotification *)note
{
CGRect keyBoardRect=[note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
self.mainTableView.contentInset = UIEdgeInsetsMake(0, 0, keyBoardRect.size.height, 0);
}
#pragma mark 键盘消失
-(void)keyboardWillHide:(NSNotification *)note
{
self.mainTableView.contentInset = UIEdgeInsetsMake(0, 0,-10, 0);
}