iPad拆分键盘、浮动键盘的显示

常见的键盘通知

UIKeyboardWillShowNotification 显示键盘的时候立即发出该通知 
UIKeyboardDidShowNotification 显示键盘后才发出该通知 
UIKeyboardWillHideNotification 键盘即将消失的时候立即发出该通知 
UIKeyboardDidHideNotification 键盘消失后才发出该通知 
UIKeyboardWillChangeFrameNotification 键盘的frame值发生变化的时候立即发出该通知 
UIKeyboardDidChangeFrameNotification 键盘的frame值发生变化后才发出该通知

键盘动画的信息

notification.userInfo
{
    UIKeyboardAnimationCurveUserInfoKey = 7;//动画曲线类型  
    UIKeyboardAnimationDurationUserInfoKey = "0.25";//动画持续时间 
    UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {414, 226}}";//键盘的bounds
    UIKeyboardCenterBeginUserInfoKey = "NSPoint: {207, 849}";//键盘动画起始时的中心点  
    UIKeyboardCenterEndUserInfoKey = "NSPoint: {207, 623}";//键盘动画结束时的中心点  
    UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 736}, {414, 226}}";//键盘动画起始时的frame
    UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 510}, {414, 226}}";//键盘动画结束时的frame
    UIKeyboardIsLocalUserInfoKey = 1;//键盘是否显示，bool类型，1 show，2 hide
}

由于iPad有拆分键盘的功能，所以只能通过ChangeFrameNotification通知去判断键盘的显示与隐藏。
按照项目要求，还需加上一个输入条随着键盘的高度变化而变化。
目前做的不完美，还在完善：

//添加键盘相关的通知
- (void)handleKeyboardNotf
{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];
}

//删除键盘相关的通知
- (void)removeKeyboardNotf
{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillChangeFrameNotification object:nil];
}

- (void)handleKeyboardillChangeFrame:(NSNotification *)notification {
    CGRect keyboardBeginFrame = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
    CGRect keyboardEndFrame = [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGFloat keyboardBeginY = keyboardBeginFrame.origin.y;
    CGFloat keyboardEndY = keyboardEndFrame.origin.y;
    
    if(fabs(CGRectGetHeight(keyboardBeginFrame)-CGRectGetHeight(keyboardEndFrame))==55 || CGRectGetHeight(keyboardBeginFrame) == CGRectGetHeight(keyboardEndFrame))
    {
        BOOL isShow = (keyboardBeginY-keyboardEndY)>0;
        if (isShow) {//显示
            self.inputView.hidden = NO;
            self.maskView.hidden = NO;
            float animationDuration = [[[notification userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
            [UIView animateWithDuration:animationDuration animations:^{
                self.inputView.frame = CGRectMake(0, keyboardEndY-InputViewH, SCREEN_WIDTH, InputViewH);
            }];
        }else{//隐藏
            float animationDuration = [[[notification userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
            [UIView animateWithDuration:animationDuration animations:^{
                self.inputView.frame = CGRectMake(0, self.frame.size.height, self.frame.size.width, InputViewH);
            } completion:^(BOOL finished) {
                if (keyboardEndY>=SCREEN_HEIGHT) {
                    [self hidSendView];
                }
            }];
        }
    }else{//键盘切换状态
        float animationDuration = [[[notification userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
        [UIView animateWithDuration:animationDuration animations:^{
            self.inputView.hidden = NO;
            self.maskView.hidden = NO;
            if (keyboardEndY==0) {
                self.inputView.frame = CGRectMake(0, STATUSBAR_HEIGHT, SCREEN_WIDTH, InputViewH);
            }else{
                self.inputView.frame = CGRectMake(0, keyboardEndY-InputViewH, SCREEN_WIDTH, InputViewH);
            }
        } completion:^(BOOL finished) {
        }];
    }
}

参考资料：https://www.jianshu.com/p/0dc4e1b05c60