具体思路

通过UIKeyboardWillChangeFrameNotification通知，监听键盘的改变，同时可以得到键盘的Frame和动画的持续时间，

新建键盘顶部工具条YSComposeToolBar,默认在底部，Y值随着键盘的改变而改变，会一直显示在键盘的最上面，动画持续时间使用步骤一通知得到的时间

新建一个存放表情的YSEmoticonKeyboard（由YSEmoticonListView + YSEmoticonTabBar）整体View，替换掉原生的键盘。其中YSEmoticonListView指的是表情列表，YSEmoticonTabBar指的是表情类型，如：浪小花、默认表情、QQ表情等。

YSEmoticonListView由UIScrollView+UIPageController 组成。UIScrollView存放着由YSEmoticonPageView装着很多表情（Button）的列表组成。

所有的界面控制操作，都封装在YSComposeViewController的控制器中里。

部分代码说明

1.键盘通知

打印一下键盘的UIKeyboardWillChangeFrameNotification通知，我们可以得到键盘的Frame和动画的持续时间。

{name = UIKeyboardWillChangeFrameNotification; userInfo = {    UIKeyboardAnimationCurveUserInfoKey = 7;    UIKeyboardAnimationDurationUserInfoKey = 0;    UIKeyboardBoundsUserInfoKey = "NSRect: {
    {0, 0}, {320, 252}}";    UIKeyboardCenterBeginUserInfoKey = "NSPoint: {160, 441.5}";    UIKeyboardCenterEndUserInfoKey = "NSPoint: {160, 442}";    UIKeyboardFrameBeginUserInfoKey = "NSRect: {
    {0, 315}, {320, 253}}";    UIKeyboardFrameEndUserInfoKey = "NSRect: {
    {0, 316}, {320, 252}}";    UIKeyboardIsLocalUserInfoKey = 1;}}

键盘的Frame和动画的持续时间

NSDictionary *userInfo = notification.userInfo;    // 动画的持续时间    double duration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];    // 键盘的frame    CGRect keyboardF = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

2.替换掉原来的键盘

self.textView.inputView == nil : 使用的是系统自带的键盘

self.textView.inputView = self.emoticonKeyboard; 指的是用表情view替换掉原来的键盘

懒加载一个View

#pragma mark - 懒加载- (YSEmoticonKeyboard *)emoticonKeyboard{    if (!_emoticonKeyboard) {        self.emoticonKeyboard = [[YSEmoticonKeyboard alloc] init];        // 键盘的宽度        self.emoticonKeyboard.width = self.view.width;        self.emoticonKeyboard.height = 216;    }    return _emoticonKeyboard;}

替换掉原来的键盘

/** *  切换键盘 */- (void)switchKeyboard{    // self.textView.inputView == nil : 使用的是系统自带的键盘    if (self.textView.inputView == nil) { // 切换为自定义的表情键盘        self.textView.inputView = self.emoticonKeyboard;        // 显示键盘按钮        self.toolbar.showKeyboardButton = YES;    } else { // 切换为系统自带的键盘        self.textView.inputView = nil;                // 显示表情按钮        self.toolbar.showKeyboardButton = NO;    }        // 开始切换键盘    self.switchingKeybaord = YES;        // 退出键盘    [self.textView endEditing:YES];        // 结束切换键盘    self.switchingKeybaord = NO;        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{        // 弹出键盘        [self.textView becomeFirstResponder];    });}