How to parse json in flutter

Question

I am trying to fetch the JSON data coming by the Http library. I would like to diplay only the "alert_description" value for the first object to user. How i can access to this attribut ?

My API respone :

{
    "code": 0,
    "message": " success",
    "data": {
        "data": {
            "current_page": 1,
            "data": [
                {
                    "id": 62,
                    "user_id": 53,
                    "boxIdentifiant": 1924589682265245,
                    "boxName": "Box Sfax",
                    "alert_date": "2021-05-30",
                    "alert_time": "09:40",
                    "alert_description": "Panne Pression",
                    "alert_level": "warning"
                },
                {
                    "id": 61,
                    "user_id": 53,
                    "boxIdentifiant": 1924589682265243,
                    "boxName": "Box Tunis",
                    "alert_date": "2021-05-30",
                    "alert_time": "09:40",
                    "alert_description": "Panne Pression Roux",
                    "alert_level": "info"
                },
                {
                    "id": 58,
                    "user_id": 53,
                    "boxIdentifiant": 1924589682265244,
                    "boxName": "Box Office",
                    "alert_date": "2021-05-30",
                    "alert_time": "09:40",
                    "alert_description": "Panne Pression Roux",
                    "alert_level": "warning"
                },

My code :

 var response =
        await http.get(Uri.parse(ApiUtil.GET_ALERT), headers: headers);
    print("here================");
    // print(response);
    var data = json.decode(response.body);
    print(data['data']['data']['data']);
    if (data['status'] == 200) {
      showNotification(data['message'], flp);
    } else {
      print("no message");
    }

    return Future.value(true);
  });
}

https://stackoverflow.com/questions/51601519/how-to-decode-json-in-flutter — SARVESH TANDON, Jun 06 '21 at 11:38
I strongly recomend using json.decode(). https://stackoverflow.com/questions/51601519/how-to-decode-json-in-flutter — SARVESH TANDON, Jun 06 '21 at 11:40

score 1 · Accepted Answer · answered Jun 06 '21 at 10:26

1

I dunno how Http library works, but in Dio library you don't need to do decode anything, it's pretty straight forward. See if this helps you:

var response = await Dio().post(yourUrl, data: { param1: value1, param2: value2 });

for (var item in response.data['data']['data']['data'])
{
    print(item['alert_description']);
}

Since you're using the GETmethod, use Dio().get() and queryParameters: instead of Dio().post() and data: respectively.

answered Jun 06 '21 at 10:26

Linesofcode

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I would like to display only the first value to user as Notification . this show me all value exist in the list . @Linesofcode – lucky Jun 06 '21 at 10:56
1

Try response.data['data']['data']['data'][0] – Muhtar Jun 06 '21 at 10:57
1

Just make sure your array length is at least 1 to avoid future problems. Follow the @AlperenBaskaya solution. – Linesofcode Jun 06 '21 at 10:58
if (data['status'] == 200) { showNotification(dataa[0]['alert_description'], flp); } else { print("no message"); } . the value display on console . i want to display it on screen as notification .@Linesofcode – lucky Jun 06 '21 at 11:03

score 0 · Answer 2 · answered Jun 06 '21 at 11:48

For decoding a JSON like this

{
"id":"xx888as88",
"timestamp":"2020-08-18 12:05:40",
"sensors":[
    {
     "name":"Gyroscope",
     "values":[
         {
          "type":"X",
          "value":-3.752716,
          "unit":"r/s"
         },
         {
           "type":"Y",
           "value":1.369709,
           "unit":"r/s"
         },
         {
           "type":"Z",
           "value":-13.085,
           "unit":"r/s"
         }
       ]
    }
  ]
}

You can do this:

void setReceivedText(String text) {
    Map<String, dynamic> jsonInput = jsonDecode(text);
    
    _receivedText = 'ID: ' + jsonInput['id'] + '\n';
    _receivedText += 'Date: ' +jsonInput['timestamp']+ '\n';
    _receivedText += 'Device: ' +jsonInput['sensors'][0]['name'] + '\n';
    _receivedText += 'Type: ' +jsonInput['sensors'][0]['values'][0]['type'] + '\n';
    _receivedText += 'Value: ' +jsonInput['sensors'][0]['values'][0]['value'].toString() + '\n';
    _receivedText += 'Type: ' +jsonInput['sensors'][0]['values'][1]['type'] + '\n';
    _receivedText += 'Value: ' +jsonInput['sensors'][0]['values'][1]['value'].toString() + '\n';
    _receivedText += 'Type: ' +jsonInput['sensors'][0]['values'][2]['type'] + '\n';
    _receivedText += 'Value: ' +jsonInput['sensors'][0]['values'][2]['value'].toString();
     _historyText = '\n' + _receivedText;
}

How to parse json in flutter

2 Answers2