UITextView有inputView 和 inputAccessoryView 两个属性，都指定了对应的视图。 inputAccessoryView 对象显示在 inputView 对象的上面。与输入相关的另一个 reloadInputViews 方法用来又一次加载输入视图。如图：UITextView自己定义键盘和系统键盘_加载

代码：

 if (bt.selected == YES) {
        bt.selected = NO;
        [m_textView setInputView:nil];
        [m_textView becomeFirstResponder];
    }else if(bt.selected == NO){
        addEmojiImgView = [AddEmojiImgView initEmojiImgView];
        [m_textView setInputView:addEmojiImgView];
        bt.selected = YES;
        [m_textView becomeFirstResponder];
    }
    [m_textView reloadInputViews];