Flutter if-else statement

Question

{"data":[{"id":"32f","regionName":"Korea","companyName":"Machine","catDealerCode":null},{"id":"cbb","regionName":"Korea","companyName":"KR","catDealerCode":null},{"id":"b6125b0e-5ec9",,"regionName":"China","companyName":"CHN","catDealerCode":null}],"code":0,"message":null}

I have data like the one you see above. I extract data according to the companyName. but some countries don't have data. I want to create an if else case within this.but no matter what I do when I say element == null it doesn't accept. Does anyone know where I am doing wrong? How should I create an if else for empty data?

  onTap: () async {
        List<Country> country =
            await fetchList(
              snapshot.data.code);
    
   country.forEach((element) {
         if(element.companyName == null){
       print('element is empty');
     }else{
          print('Here ${element.companyName}');
                                        }
         });
            },

And here's my country list data;

{"data":[{{"code":"KR","name":"Korea","isActive":true,"id":"71"},{"code":"RU","name":"Rusia","isActive":true,"id":"3c"},{"code":"Ch","name":"China","isActive":true,"id":"86"}],"code":0,"message":null}

 class Country {
  String id;
  String companyCode;
  String countryCode;
  String countryId;
  String regionName;
  String companyName;
  Null catDealerCode;

  Country(
      {this.id,
        this.companyCode,
        this.countryCode,
        this.countryId,
        this.regionName,
        this.companyName,
        this.catDealerCode});

  Couuntry.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    companyCode = json['companyCode'];
    countryCode = json['countryCode'];
    countryId = json['countryId'];
    regionName = json['regionName'];
    companyName = json['companyName'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['companyCode'] = this.companyCode;
    data['countryCode'] = this.countryCode;
    data['countryId'] = this.countryId;
    data['regionName'] = this.regionName;
    data['companyName'] = this.companyName;
    return data;

} }

Please format and indent your code correctly otherwise no one will help you. — user10191234
– user10191234, Commented Sep 6, 2020 at 22:23
sorry, i'm new here. I still can't get used to it,is it more organized this way? I didn't want to copy the whole page because this is where the relevant part. Sometimes I get a warning like 'extend the description' when I write too much code, — kimSoo
– kimSoo, Commented Sep 6, 2020 at 22:28
Is the companyName really null or it is just an empty string ? Can you add an example where a Company doesn't have a companyName ? @kimSoo — timilehinjegede
– timilehinjegede, Commented Sep 6, 2020 at 22:42
actually if there is no companyName it is not included in the data — kimSoo
– kimSoo, Commented Sep 6, 2020 at 22:45

Mike · Accepted Answer · 2020-09-06 22:27:28Z

1

I would go with null-aware operator:

onTap: () async {
                              List<Country> country =
                                        await fetchList(
                                            snapshot.data.code);
    
                                      country?.forEach((element) {
                                        if(element?.companyName == null){
                                          print('element is empty');
                                        }else{
                                          print('Here ${element.companyName}');
                                        }
                                      });
                          },

answered Sep 6, 2020 at 22:27

Mike

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5 Comments

kimSoo Over a year ago

I tried this solution but it doesn't work:/. It prints as 'Here....', but when pressing the empty item it does not say 'element is empty'

kimSoo Over a year ago

I'm pulling it from a different data but I added it to my question

Mike Over a year ago

Add your country class to your question too please.

kimSoo Over a year ago

I added my country class

Mike Over a year ago

My guess here is that you are using json_serializable package, with nullable set to default(which is true), which must return you an empty string for your element.companyName when null. Pretty sure you could do if(element?.companyName == null || element?.companyName?.isEmpty) (But i don't like this solution so much...)

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