iOS 系统数字键盘左下角加确定按钮

首先在 viewWillAppear 方法中注册监听相应的键盘通知，并且要在 viewWillDisappear 方法中注销通知
- (void)viewWillAppear:(BOOL)animated {

    [super viewWillAppear:animated];
    //注册键盘显示通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardDidShow:) name:UIKeyboardWillShowNotification object:nil];
    //注册键盘隐藏通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}

-(void)viewWillDisappear:(BOOL)animated{

    [super viewWillDisappear:animated];
    //注销键盘显示通知
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

处理键盘弹出和收起事件

// 键盘出现处理事件
- (void)handleKeyboardDidShow:(NSNotification *)notification
{
    // NSNotification中的 userInfo字典中包含键盘的位置和大小等信息
    NSDictionary *userInfo = [notification userInfo];
    // UIKeyboardAnimationDurationUserInfoKey 对应键盘弹出的动画时间
    CGFloat animationDuration = [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
    // UIKeyboardAnimationCurveUserInfoKey 对应键盘弹出的动画类型
    NSInteger animationCurve = [[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] integerValue];
    //数字彩,数字键盘添加“完成”按钮
    if (doneInKeyboardButton){

        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDuration:animationDuration];//设置添加按钮的动画时间
        [UIView setAnimationCurve:(UIViewAnimationCurve)animationCurve];//设置添加按钮的动画类型

        //设置自定制按钮的添加位置(这里为数字键盘添加“完成”按钮)
        doneInKeyboardButton.transform=CGAffineTransformMakeTranslation(, -);

        [UIView commitAnimations];
    }

}

// 键盘消失处理事件
- (void)handleKeyboardWillHide:(NSNotification *)notification
{
    // NSNotification中的 userInfo字典中包含键盘的位置和大小等信息
    NSDictionary *userInfo = [notification userInfo];
    // UIKeyboardAnimationDurationUserInfoKey 对应键盘收起的动画时间
    CGFloat animationDuration = [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];

    if (doneInKeyboardButton.superview)
    {
        [UIView animateWithDuration:animationDuration animations:^{
            //动画内容，将自定制按钮移回初始位置
            doneInKeyboardButton.transform=CGAffineTransformIdentity;
        } completion:^(BOOL finished) {
            //动画结束后移除自定制的按钮
            [doneInKeyboardButton removeFromSuperview];
        }];

    }
}

在textField代理中调用加载按钮方法

#pragma mark -- UITextFieldDelegate
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    //初始化数字键盘的“完成”按钮
    if(doneInKeyboardButton.superview==nil)
        [self configDoneInKeyBoardButton];
}

- (void) addDoneButton{
    //获得键盘所在的window视图
    NSArray *array= [[UIApplication sharedApplication]windows];

    for (UIWindow *window in array) {

        NSString *str=NSStringFromClass([window class]);

        if ([str isEqualToString:@"UIRemoteKeyboardWindow"]) {

            [window addSubview:doneInKeyboardButton];

        }

    }

}

//点击“完成”按钮事件，收起键盘
-(void)finishAction{
    [[[UIApplication sharedApplication] keyWindow] endEditing:YES];//关闭键盘
}

如果用户安装了其他输入法，会出错，因此在APPDelegate中禁止第三方的输入法

-(BOOL)application:(UIApplication *)application shouldAllowExtensionPointIdentifier:(NSString *)extensionPointIdentifier{

    return NO;
}