I have a widget that gets title from a webpage which is :

Widget ref_box(BuildContext context,String reference){
  Future <String> scrap_title(url_received) async
  {
    print('response init');
    if (url_received =='' || url_received ==' ') return 'No reference';
    final url = Uri.parse(url_received);
    print('response parsed');
    final resp = await http.get(url);
    print('response on');
    var elements;
    if (resp.statusCode ==200){
      dom.Document doc = parser.parse(resp.body);
      elements = doc.querySelector('title');
      //    final linkElemnt=doc.getElementsByClassName('entry-title');
      //var html = dom.Document.html(resp.body).head!.text.trim();
    }

    return Future.value(elements!.text);
  }
  return Column(
    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
    crossAxisAlignment: CrossAxisAlignment.start,
    children: [
      Padding(padding: EdgeInsets.symmetric(vertical: 3)),

      FutureBuilder<String>(
        future: scrap_title(reference),
        builder: (BuildContext context, AsyncSnapshot snapshot){
          if (snapshot.hasData == false) {
            return CircularProgressIndicator();
          }
          else
            return Text(snapshot.data);
        },
      ),
      //Text(ref_title),
      Padding(padding: EdgeInsets.symmetric(vertical: 3))
    ],
  );
}

I called this ref_box two times, one in stateful class and one in dialog.

The dialog-calling code is as following :

void Function()? _showPost_Dialog(String content, String writer, int like,int shared,String ref) {

    showDialog(
      context: context,
      builder: (context) {
        String lls = like.toString();
        // return object of type Dialog
        return
          Dialog(
            shape: RoundedRectangleBorder(
                borderRadius:
                BorderRadius.circular(10.0)), //this right here

            child:
            Container(height: MediaQuery.of(context).size.height*0.7,
            padding: EdgeInsets.symmetric(horizontal: 10),
            child:GestureDetector(onTap: (){
                  if(ref==' ' ||ref=='') {
                    print('Reference 없음');
                    return;
                  }
                  _showWeb(writer, ref);
                },
                  child: ref_box(context, ref),
                ),
);

This _showPost_Dialog() is called when a GestureDetector is pressed.

I confirmed that ref_box() called at a class worked well however one called at _showPost_Dialog() did not. The print code told me that await http.get(url); does not work when it is called in _showPost_Dialog().

Why does this happen ? What should I do to make this work even in dialog?

CodePudding user response：

This function takes a builder which typically builds a Dialog widget. Content below the dialog is dimmed with a ModalBarrier. The widget returned by the builder does not share a context with the location that showDialog is originally called from. Use a StatefulBuilder or a custom StatefulWidget if the dialog needs to update dynamically.

So the easiest solution (and better anyway, even if it had worked) would be to take your ref_box method and make a proper StatefulWidget from it. Then you can store your Future in your state, too, instead of calling the producing method (potentially multiple times) in your build method.