calculate-keyboard-height.js

constructor(props) {
    super(props)
    this.state = {
        isKeyboardShow: false,
        keyboardHeight: 0,
    }
}

componentWillMount() {
    this.keyboardDidShowListener = Keyboard.addListener(
        'keyboardDidShow',
        this.keyboardDidShow
    )
    this.keyboardDidHideListener = Keyboard.addListener(
        'keyboardDidHide',
        this.keyboardDidHide
    )
}

componentWillUnmount() {
    this.keyboardDidShowListener.remove()
    this.keyboardDidHideListener.remove()
}

keyboardDidShow = (e) => {
    this.setState({
        isKeyboardShow: true,
        keyboardHeight: e.endCoordinates.height
    })
}

keyboardDidHide = () => {
    this.setState({
        isKeyboardShow: false
    })
}