Swift4 获取键盘高度

cocopods导入：

import RxSwift

import RxCocoa

import RxKeyboard

声明一个常量，storyboard拖拽一个UITextView：

let disposeBag = DisposeBag()

@IBOutlet weak var enterText: UITextView!

viewDidLoad()函数里面添加以下代码：

RxKeyboard.instance.frame

        .drive(onNext: { frame in

             if frame.origin.y == UIScreen.main.bounds.height {

                    UIView.animate(withDuration: 0.4, animations: {

                        enterText.frame = CGRect(x: 0, y: frame.origin.y, width: frame.width, height: 120)

             })

             } else {

                    UIView.animate(withDuration: 0.4, animations: {

                        enterText.frame = CGRect(x: 0, y: frame.origin.y - 120, width: frame.width, height: 120)

            })

            }

}

})

.disposed(by: disposeBag)