How to execute requests in order?

Question

I make 3 requests in a row, but they are fired in processing order, not synchronously, how can I resolve this?

...

//botão pressionado
// primeira requisição

ivUpload.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

             /* auto completes */

            txt_estados = (AutoCompleteTextView)
                    findViewById(R.id.txt_estado);
            txt_cidades = (AutoCompleteTextView)
                    findViewById(R.id.txt_cidade);
            txt_bairros = (AutoCompleteTextView)
                    findViewById(R.id.txt_bairro);

            final String estado = txt_estados.getText().toString().trim();
            final String cidade = txt_cidades.getText().toString().trim();
            final String bairro = txt_bairros.getText().toString().trim();
            final String metrosQ = txt_metrosQ.getText().toString().trim();
            final String quartos = txt_quartos.getText().toString().trim();
            final String garagens = txt_garagens.getText().toString().trim();
            final String cep = txt_cep.getText().toString().trim();
            final String complemento = txt_complemento.getText().toString().trim();
            final String preco = txt_preco.getText().toString().trim();
            final String descricao = txt_descricao.getText().toString().trim();
            final String map = txt_map.getText().toString().trim();

            final RadioGroup Rdtipo = (RadioGroup) findViewById(R.id.rd_tipo);
            int ntipo = Rdtipo.getCheckedRadioButtonId();


            if (ntipo == R.id.Apartamento) {
                tipo = "Apartamento";
            } else if (ntipo == R.id.Barracao) {
                tipo = "Barracão";
            }else if (ntipo == R.id.Residencial) {
                tipo = "Residêncial";
            }else if (ntipo == R.id.Terreno) {
                tipo = "Terreno";
            }else if (ntipo == R.id.Kitinete) {
                tipo = "Kitinete";
            }

            final RadioGroup RdtipoNeg = (RadioGroup) findViewById(R.id.rd_tipoNeg);
            int ntipoNeg = Rdtipo.getCheckedRadioButtonId();


            if (ntipoNeg == R.id.A) {
                tipoNeg = "A";
            } else if (ntipoNeg == R.id.C) {
                tipoNeg = "C";
            }

            final String idUser = "51"; // <-- aqui o id do usuario

            final MyCommand myCommander = new MyCommand(getApplicationContext());

            try{

                String url = "http://a4da1ea4.ngrok.io/upVariasImgs/solicitarAvaliacao.php";
                StringRequest stringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        Toast.makeText(getApplicationContext(), response, Toast.LENGTH_SHORT).show();


                        idImovel = response;


                        responseList.add(response);

                        cadImgs(); <-- chamo a segunda requisição

                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getApplicationContext(), "Erro ao fazer upload da imagem", Toast.LENGTH_SHORT).show();
                    }
                }) {
                    @Override
                    protected Map<String, String> getParams() throws AuthFailureError {
                        Map<String, String> params = new HashMap<>();
                        params.put("metrosQ", metrosQ);
                        params.put("quartos", quartos);
                        params.put("garagens", garagens);
                        params.put("cep", cep);
                        params.put("complemento", complemento);
                        params.put("descricao", descricao);
                        params.put("mapa", map);
                        params.put("estado", estado);
                        params.put("cidade", cidade);
                        params.put("bairro", bairro);
                        params.put("tipo", tipo);
                        params.put("tipoNeg", tipoNeg);
                        params.put("preco", preco);
                        params.put("idUser", idUser);
                        return params;
                    }
                };

                myCommander.add(stringRequest);

            } catch (NullPointerException e) {
                Toast.makeText(getApplicationContext(), "Erro ao fazer upload da imagem", Toast.LENGTH_SHORT).show();
            }


            myCommander.execute();








        }
    });
}

when pressing the ivUpload button, the first request is triggered, where the property is saved in the database and returned its id by json

//segunda requisição
public void cadImgs() {
    final MyCommand myCommand = new MyCommand(getApplicationContext());


    for(String imagePath: imageList){
        try {
            Bitmap bitmap = PhotoLoader.init().from(imagePath).requestSize(512, 512).getBitmap();
            final String encodedString = ImageBase64.encode(bitmap);


            String url = "http://a4da1ea4.ngrok.io/upVariasImgs/upload.php";
            StringRequest stringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    Toast.makeText(getApplicationContext(), response, Toast.LENGTH_SHORT).show();


                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(getApplicationContext(), "Erro ao fazer upload da imagem", Toast.LENGTH_SHORT).show();
                }
            }){
                @Override
                protected Map<String, String> getParams() throws AuthFailureError {
                    Map<String, String> params = new HashMap<>();
                    params.put("image", encodedString);
                    params.put("idImo", idImovel);
                    return params;
                }
            };

            myCommand.add(stringRequest);

        } catch (FileNotFoundException e) {
            Toast.makeText(getApplicationContext(), "Erro ao fazer upload da imagem", Toast.LENGTH_SHORT).show();
        }
    }


    myCommand.execute();
    somaId(); <-- está executando antes do loop acima
}


//terceira requisição
public void somaId(){
    ...
}

soon after I pick up this id for the second request, cadImgs() method, which is fired in the json response of the first request, until then it follows the order, but the second request is within a loop

for this reason I did not call the third function somaId() in the server response but after the loop ended, which causes it to break this order, and perform the function somaId, before the loop

Answer 1

From what is perceived then, one request is dependent on the other. In order to work correctly, you must call the next request only if the first request has already returned some result. As it is working asynchronously, running in processing mode, it does not have a set time to finish any kind of query.

An example of problem solving is you calling a second request within your StringRequest, which in this case will only be executed at the end of the first request. See

StringRequest stringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String> () {
   @Override
   public void onResponse(String response) {

   // só será chamada a segunda requisição aqui dentro, pois já terá obtido a  resposta
   // da primeira requisição
   chamaSegundaRequisicao();
   }
}