how i can display data fetching from api in flutter

Use serializable class map with your responce object

Sample Json responce

{
  "glossary": {
    "title": "example glossary",
    "GlossDiv": {
      "title": "S",
      "GlossList": {
        "GlossEntry": {
          "ID": "SGML",
          "SortAs": "SGML",
          "GlossTerm": "Standard Generalized Markup Language",
          "Acronym": "SGML",
          "Abbrev": "ISO 8879:1986",
          "GlossDef": {
            "para": "A meta-markup language, used to create markup languages such as DocBook.",
            "GlossSeeAlso": [
              "GML",
              "XML"
            ]
          },
          "GlossSee": "markup"
        }
      }
    }
  }
}

Your sampleSerializable class

import 'dart:convert';

SampleSerializable sampleSerializableFromJson(String str) => SampleSerializable.fromJson(json.decode(str));

String sampleSerializableToJson(SampleSerializable data) => json.encode(data.toJson());

class SampleSerializable {
    SampleSerializable({
        this.glossary,
    });

    final Glossary glossary;

    factory SampleSerializable.fromJson(Map<String, dynamic> json) => SampleSerializable(
        glossary: json["glossary"] == null ? null : Glossary.fromJson(json["glossary"]),
    );

    Map<String, dynamic> toJson() => {
        "glossary": glossary == null ? null : glossary.toJson(),
    };
}

class Glossary {
    Glossary({
        this.title,
        this.glossDiv,
    });

    final String title;
    final GlossDiv glossDiv;

    factory Glossary.fromJson(Map<String, dynamic> json) => Glossary(
        title: json["title"] == null ? null : json["title"],
        glossDiv: json["GlossDiv"] == null ? null : GlossDiv.fromJson(json["GlossDiv"]),
    );

    Map<String, dynamic> toJson() => {
        "title": title == null ? null : title,
        "GlossDiv": glossDiv == null ? null : glossDiv.toJson(),
    };
}

class GlossDiv {
    GlossDiv({
        this.title,
        this.glossList,
    });

    final String title;
    final GlossList glossList;

    factory GlossDiv.fromJson(Map<String, dynamic> json) => GlossDiv(
        title: json["title"] == null ? null : json["title"],
        glossList: json["GlossList"] == null ? null : GlossList.fromJson(json["GlossList"]),
    );

    Map<String, dynamic> toJson() => {
        "title": title == null ? null : title,
        "GlossList": glossList == null ? null : glossList.toJson(),
    };
}

class GlossList {
    GlossList({
        this.glossEntry,
    });

    final GlossEntry glossEntry;

    factory GlossList.fromJson(Map<String, dynamic> json) => GlossList(
        glossEntry: json["GlossEntry"] == null ? null : GlossEntry.fromJson(json["GlossEntry"]),
    );

    Map<String, dynamic> toJson() => {
        "GlossEntry": glossEntry == null ? null : glossEntry.toJson(),
    };
}

class GlossEntry {
    GlossEntry({
        this.id,
        this.sortAs,
        this.glossTerm,
        this.acronym,
        this.abbrev,
        this.glossDef,
        this.glossSee,
    });

    final String id;
    final String sortAs;
    final String glossTerm;
    final String acronym;
    final String abbrev;
    final GlossDef glossDef;
    final String glossSee;

    factory GlossEntry.fromJson(Map<String, dynamic> json) => GlossEntry(
        id: json["ID"] == null ? null : json["ID"],
        sortAs: json["SortAs"] == null ? null : json["SortAs"],
        glossTerm: json["GlossTerm"] == null ? null : json["GlossTerm"],
        acronym: json["Acronym"] == null ? null : json["Acronym"],
        abbrev: json["Abbrev"] == null ? null : json["Abbrev"],
        glossDef: json["GlossDef"] == null ? null : GlossDef.fromJson(json["GlossDef"]),
        glossSee: json["GlossSee"] == null ? null : json["GlossSee"],
    );

    Map<String, dynamic> toJson() => {
        "ID": id == null ? null : id,
        "SortAs": sortAs == null ? null : sortAs,
        "GlossTerm": glossTerm == null ? null : glossTerm,
        "Acronym": acronym == null ? null : acronym,
        "Abbrev": abbrev == null ? null : abbrev,
        "GlossDef": glossDef == null ? null : glossDef.toJson(),
        "GlossSee": glossSee == null ? null : glossSee,
    };
}

class GlossDef {
    GlossDef({
        this.para,
        this.glossSeeAlso,
    });

    final String para;
    final List<String> glossSeeAlso;

    factory GlossDef.fromJson(Map<String, dynamic> json) => GlossDef(
        para: json["para"] == null ? null : json["para"],
        glossSeeAlso: json["GlossSeeAlso"] == null ? null : List<String>.from(json["GlossSeeAlso"].map((x) => x)),
    );

    Map<String, dynamic> toJson() => {
        "para": para == null ? null : para,
        "GlossSeeAlso": glossSeeAlso == null ? null : List<dynamic>.from(glossSeeAlso.map((x) => x)),
    };
}

And map your responce in getprofile method

 SampleSerializable sampleSerializableModel = SampleSerializable.fromJson(response);

Now you can access value as object

sampleSerializableModel.Glossary.title

fetching data from api

Future<TrueOrFalse > freeaccess() async {
  String userid = await getUserId();
  var map = new Map<String, String>();
  map['userid'] = userid;
  var response = await http
      .post(Constants.ApiBaseUrl + '/free_access_check.php', body: map);
  if (response.statusCode == 200) {
    print("freeaccess response userid $userid" + response.body);

    TrueOrFalse trueOrFalse = TrueOrFalse.fromJson(json.decode(response.body));

    if (trueOrFalse.status == "sucess") {
      return true;
    } else {
      return false;
    }
  } else {
    throw Exception('Failed to crate login session');
  }
}

TrueOrFalse is the data model. getting data from the api caling function

@override
  void initState() {
    freeaccess().then((value) => {
          print(value);
        });
    super.initState();
}