Popular Listview Shapes with Retrofit 2

Question

Although there is already a similar question, not clarified my doubt, my problem is the following, the code below is from onResponse of Retrofit, I’m starting now in Java, I would like to play the result of Response.body in listview, i managed by doing a for in stringlist.add(countryList.get(i) code. getNome()), however I would like to know if there would be a better way to do it, I saw some examples using Course, but my requests will return about 1400 lines so I do not know if using is can compromise performance, thought if there could not be another more elegant way to do, in the code below I tried to play the List with the direct Replay.body() in Arrayadapter, only that this way the app returns the data so:

public void onResponse(Call < List < Funcionarios >> call, Response < List < Funcionarios >> response) {
  try {

    List < String > stringList = new ArrayList < > ();
    ListView lista = (ListView)findViewById(R.id.ListView);
    TextView qtdtotal = (TextView) findViewById(R.id.textView);
    List < Funcionarios > countryList = response.body();

    ArrayAdapter adapter = new ArrayAdapter < > (getApplicationContext(), android.R.layout.simple_list_item_1, countryList);
     

lista.setAdapter(adapter)

} catch (Exception e) {
  Log.d("onResponse", "There is an error");
  e.printStackTrace();
}

@GET("/webservice/webservice.php")
Call < List < Funcionarios >> getFunc(@Query("empresa") String empresa);

public class Funcionarios{
    @SerializedName("NOME")
    private String nome;
    @SerializedName("MAT")
    private int matricula;
    @SerializedName("EMP")
    private int empresa;

    private List<Funcionarios> lsfunc = null;
    public List<Funcionarios> getFunc() {
        return lsfunc;
    }

    public void setFunc(List<Funcionarios> posts) {
        this.lsfunc = posts;
    }

    public int getMatricula() {return matricula ; }

    public int getEmpresa() {
        return empresa ;
    }

    public String getNome() {
        return nome;
    }

    public void setMatricula(){
        this.matricula = matricula;
    }
    public void setNome(){
        this.nome = nome;
    }
    public void setEmpresa(){
        this.empresa = empresa;
    }

}

Answer 1

Solving the problem of "1400 lines":

The ideal would be to work with paging. Instead of returning all results at once, make a request limiting the amount of items. As the scroll, you will be making a new request with another "package" of items.

See below for an example passing the limit and the page as parameter. The limit represents the amount of items you want returned to each request. The page represents which page you want to show.

@GET("/webservice/webservice.php)
Call <List<Funcionarios>> getFunc(
    @Query("empresa") String empresa,
    @Query("limit") int limit,
    @Query("page") int page,
    );

Therefore, you need to make a change to your webservice.php to recognize the parameters.

See below for an example of how to pass your query:

SELECT nome, matricula, empresa FROM tblEmpresas LIMIT 0,10

This query above, will return 10 items from the first page. See below 10 more items from the second page.

 SELECT nome, matricula, empresa FROM tblEmpresas LIMIT 1,10

So you use the received variables $_GET['limit'] and $_GET['page']:

 SELECT nome, matricula, empresa FROM tblEmpresas LIMIT $_GET['page'].','.$_GET['limit']

This is just an example on top based on what you want to do.

Solving of object printing:

The second problem is that you are printing an object in the list and not a single one string. To resolve you cannot enter response.body() directly to countryList. You have to wear something like:

List <Funcionarios> countryList = response.body().getFunc();

And there’s another thing, as it’s a list of objects, you would have to create a Adapter customized. See here an example how create a custom list: