//首先注册通知，监听键盘：

- (void)viewDidLoad {    [super viewDidLoad];    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillAppear:) name:UIKeyboardWillShowNotification object:nil];    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillDisAppear:) name:UIKeyboardWillHideNotification object:nil];}

 //在键盘弹出和收起的方法中做以下操作

- (void)keyboardWillAppear:(NSNotification *)noti {    NSDictionary *userInfo = noti.userInfo;    //获取键盘的frame    CGRect keyboardFrame = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];    //获取键盘弹出的动画时间    NSTimeInterval animationDuration = [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey ] doubleValue];    //让输入框跟随变化    [UIView animateWithDuration:animationDuration animations:^{       [_ctv mas_updateConstraints:^(MASConstraintMaker *make) {           make.bottom.equalTo(@(-keyboardFrame.size.height));       }];    }];    //设置tableview的contentInset属性，改变tableview的显示范围    _tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardFrame.size.height, 0);    _tableView.scrollEnabled = YES;}- (void)keyboardWillDisAppear:(NSNotification *)noti {    NSDictionary *userInfo = noti.userInfo;    NSTimeInterval animationDuration = [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey ] doubleValue];    [UIView animateWithDuration:animationDuration animations:^{        [_ctv mas_updateConstraints:^(MASConstraintMaker *make) {            make.bottom.equalTo(@0);            make.height.equalTo(@52);        }];    }];    UIEdgeInsets contentInsets = UIEdgeInsetsZero;    _tableView.contentInset = contentInsets;}