ProsesLogin

public class ProsesLogin extends AsyncTask<String,Void,String> {
    //url untuk memanggil link php-nya
    private String login_uri = "Your IP/latihan/Login.php";
    Context etx;
    ProgressDialog progressDialog;
    Activity activity;
    AlertDialog.Builder builder;

    public ProsesLogin(Context etx) {
        this.etx = etx;
        activity = (Activity) etx;
    }

    @Override
    protected void onPreExecute() {
        builder = new AlertDialog.Builder(activity);
        progressDialog = new ProgressDialog(etx);
        progressDialog.setTitle("Please Wait");
        progressDialog.setMessage("Connecting to server...");
        progressDialog.setIndeterminate(true);
        progressDialog.setCancelable(false);
        progressDialog.show();
    }

    @Override
    protected String doInBackground(String... voids) {
        String method = voids[0]; //memanggil String pertama
        if (method.equals("login")) {
            try {
                URL url = new URL(login_uri);
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setDoInput(true);
                OutputStream outStream = httpURLConnection.getOutputStream();
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outStream, "UTF-8"));
                String username, password;
                username = voids[1];  //memanggil String kedua
                password = voids[2];  //memanggil String ketiga
                String data = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&" +
                                URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");
                bufferedWriter.write(data);
                bufferedWriter.flush();
                outStream.close();
                bufferedWriter.close();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                InputStream inputStream = httpURLConnection.getInputStream();
                StringBuilder stringBuilder = new StringBuilder();
                String line = "";
                while ((line = bufferedReader.readLine()) != null) {
                    stringBuilder.append(line + "\n");
                }
                httpURLConnection.disconnect();
                Thread.sleep(10000);
                return stringBuilder.toString().trim();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (ProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    // proses untuk mengetahui login itu berhasil atau tidak
    @Override
    protected void onPostExecute(String json) {
        try {
            progressDialog.dismiss();
            JSONObject jsonObject = new JSONObject(json);
            JSONArray jsonArray = jsonObject.getJSONArray("server_response");
            JSONObject JO = jsonArray.getJSONObject(0);
            String code = JO.getString("code");
            String message = JO.getString("message");
            if (code.equals("login_true")) {
                Intent intent = new Intent(activity, HomeActivity.class);
                activity.startActivity(intent);
            } else if (code.equals("login_false")) {
                EditText useroremail, pass;
                useroremail = activity.findViewById(R.id.username);
                pass = activity.findViewById(R.id.password);
                useroremail.setText("");
                pass.setText("");
                Intent intent = new Intent(activity, MainActivity.class);
                activity.startActivity(intent);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}