Close modal and update display field with custom button

[BilalBudhani]

Right button in Navigator has a very low visibility so I was thinking of adding a custom button in Modal view to close the modal and select the value. So far I'm able to close the modal but not able to update the display value of the field. Any suggestion?

        <GiftedForm.ModalWidget
          title='Recorded At'
          displayValue='recorded_at'
          scrollEnabled={false}>

          <GiftedForm.SeparatorWidget/>
          <GiftedForm.DatePickerIOSWidget
            name='recorded_at'
            mode='datetime'
            timeZoneOffsetInMinutes={this._getTimezoneOffset()}
            getDefaultDate={() => new Date() }
          />
          <Button
            onPress={() => this.props.navigator.pop()}
            style={{
              backgroundColor: '#3F5C7A',
              margin: 10,
            }}
            textStyle={{color: '#fff'}}>
            Done
          </Button>
        </GiftedForm.ModalWidget>

[dev-vinoth]

+1