使用url_launcher打开App

dependencies:
  url_launcher: ^5.4.11

_launchURL() async {
    const url = 'http://it200.cn/';
    if (await canLaunch(url)) {
      await launch(url);
    } else {
      throw 'Could not launch $url';
    }
  }

_openMap() async {
    if (Platform.isAndroid) {
      // schema
      const url = 'geo:52.32,4.917';
      if (await canLaunch(url)) {
        await launch(url);
      }
    } else if (Platform.isIOS) {
      const url = 'http://maps.apple.com/?ll=52.32,4.917';
      if (await canLaunch(url)) {
        await launch(url);
      }
    } else {
      throw '暂不支持当前平台';
    }
  }