Detect and Remove duplicates in ArrayList?

Question

I have an array with 2 positions, each one contains a list of "ids_alunos", the first position has ids_alunos: "1,2,3" and the second:"4,5" but what is happening when I add the ids in my array is this, the first position gets "1,2,3" values and the second: "1,2,3,4,5". why is this happening?

public ArrayList<CadastraEscolas> getFilhos(String mToken) throws Exception {

        String[] resposta = new WebService().get("filhos", mToken);


        if (resposta[0].equals("200")) {

            JSONObject mJSONObject = new JSONObject(resposta[1]);
            JSONArray dados = mJSONObject.getJSONArray("data");



            mArrayList = new ArrayList<CadastraEscolas>();
            mGPSList = new ArrayList<GPSEscolas>();


            for (int i = 0; i < dados.length(); i++) {


                JSONObject item = dados.getJSONObject(i).getJSONObject("escolas");
                JSONArray escolas = item.getJSONArray("data");

                for (int j = 0; j < escolas.length(); j++) {

                    JSONObject jItens = escolas.getJSONObject(j);
                    mCadastraEscolas = new CadastraEscolas();
                    mGPSEscolas = new GPSEscolas();

                    mCadastraEscolas.setId_escola(jItens.optInt("id_escola"));


                    mGPSEscolas.setId_escola(jItens.optInt("id_escola"));



                    JSONObject alunos = jItens.optJSONObject("alunos");

                    JSONArray data = alunos.getJSONArray("data");

                    if (data != null) {

                        ArrayList<Filhos> arrayalunos = new ArrayList<Filhos>();

                        for (int a = 0; a < data.length(); a++) {

                            mFilhos = new Filhos();

                            JSONObject clientes = data.getJSONObject(a);

                            mFilhos.setId_aluno(clientes.optInt("id_aluno"));



                            arrayalunos.add(mFilhos);

                            idsAlunos  += ";" + arrayalunos.get(a).getId_aluno().toString();

                            mGPSEscolas.setIds_alunos(idsAlunos);

                        }


                        mCadastraEscolas.setalunos(arrayalunos);

                    }



                    mArrayList.add(mCadastraEscolas);
                    mGPSList.add(mGPSEscolas);



                }
            }

            return mArrayList;

        } else {
            throw new Exception("[" + resposta[0] + "] ERRO: " + resposta[1]);
        }

    }

Where is the declaration of idsAlunos ? If this has a global scope, the values from the first iteration will remain for the second iteration and therefore appended to the first value. If you want to avoid this, either give idsAlunos local scope or clear the value at the beginning of each iteration — Catalina
– Catalina, Commented Jun 3, 2015 at 15:09

ci_ · Accepted Answer · 2015-06-03 15:11:03Z

1

You probably want to initialize idsAlunos at the same time as mGPSEscolas, so where you do:

mGPSEscolas = new GPSEscolas();

you could also do:

idsAlunos = "";

otherwise idsAlunos gets appended to with every new mGPSEscolas.

answered Jun 3, 2015 at 15:11

ci_

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1 Comment

AND4011002849 Over a year ago

could you take a look at my other question please? stackoverflow.com/questions/30715299/…

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