// 监听键盘通知

        NotificationCenter.default.addObserver(self, selector: #selector(ComposeViewController.keyboardWillChangeFrame(note:)), name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)

    //监听键盘的事件

    func keyboardWillChangeFrame(note: Notification) {

        print(note.userInfo ?? "")

        // 1.获取动画执行的时间

        let duration = note.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! TimeInterval

        // 2.获取键盘最终 Y值

        let endFrame = (note.userInfo?[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

        let y = endFrame.origin.y

        //计算工具栏距离底部的间距

        let margin = UIScreen.main.bounds.height - y

        print(margin)

        // 更新约束,执行动画

        toolBarBottom.snp.updateConstraints { (make) in

            make.left.equalTo()

            make.right.equalTo()

            make.height.equalTo()

            make.bottom.equalTo(-margin)

        }

        UIView.animate(withDuration: duration) {

            self.view.layoutIfNeeded()

        }

    }