Как обработать запрос с Android на Flask?

Question

oyshomusic @oyshomusic

Как обработать запрос с Android на Flask?

Здравствуйте, не могу обработать POST запрос.
При попытке отправить его на сервер, выдаёт ошибку (есть на скриншоте).
Помогите разобраться, в чём дело.

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.UnsupportedEncodingException;

public class MainActivity extends AppCompatActivity {

    private RequestQueue requestQueue;
    private EditText et_countid;
    private Button btn_submit;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        et_countid = (EditText)findViewById(R.id.et_countid);

        btn_submit = (Button) findViewById(R.id.btn_submit);

        btn_submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String data = "{"+
                        "\"countid\"" + "\"" + et_countid.getText().toString() + "\""+
                        "}";
                Submit(data);
            }
        });
    }

    private void Submit(String data)
    {
        final String savedata= data;
        String URL="http://10.0.2.2:5000/activation";

        requestQueue = Volley.newRequestQueue(getApplicationContext());
        StringRequest stringRequest = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                try {
                    JSONObject objres=new JSONObject(response);
                    Toast.makeText(getApplicationContext(),objres.toString(),Toast.LENGTH_LONG).show();


                } catch (JSONException e) {
                    Toast.makeText(getApplicationContext(),"Server Error",Toast.LENGTH_LONG).show();

                }
                //Log.i("VOLLEY", response);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {

                Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show();

                //Log.v("VOLLEY", error.toString());
            }
        }) {
            @Override
            public String getBodyContentType() {
                return "application/json; charset=utf-8";
            }

            @Override
            public byte[] getBody() throws AuthFailureError {
                try {
                    return savedata == null ? null : savedata.getBytes("utf-8");
                } catch (UnsupportedEncodingException uee) {
                    //Log.v("Unsupported Encoding while trying to get the bytes", data);
                    return null;
                }
            }

        };
        requestQueue.add(stringRequest);
    }
}

@app.route("/activation", methods=['POST', 'GET'])
def activation():
	if (request.method == "POST"):
		countid_ = request.form["countid"]
		discard = Data(countid_)
		db.session.add(discard)
		db.session.commit()
		return render_template("success.html")
	else:
		return render_template("activation.html")

<form class="contact100-form validate-form" method="POST">
				<span class="contact100-form-title">
					Активация карты
				</span>

				<div class="wrap-input100 validate-input" data-validate="Name is required">
					<input class="input100" type="number" min="100000" max="999999999" name="countid" required placeholder="Введите номер Вашей карты">
					<span class="focus-input100"></span>
				</div>

				<div class="container-contact100-form-btn">
					<div class="wrap-contact100-form-btn">
						<div class="contact100-form-bgbtn"></div>
							<button class="contact100-form-btn" type="submit">
								Подтвердить
							</button>
					</div>
				</div>
			</form>