Android Insert CheckBox value into mysql

I am programming an android app and I want to insert some String data into my mysql database. There is a CheckBox in my MainActivity. If it is checked i want to insert "Yes" to my mysql-databse and if it is unchecked I want to insert "No". Curently it don't work. I think my main problem is, that it says str_cb_gesdeutsch is never used. Why I can`t use it in "public void OnAnghinzu"?

MainActivity.java

public class MainActivity extends AppCompatActivity {
  CheckBox cb_gesdeutsch;

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

        cb_gesdeutsch = (CheckBox) findViewById(R.id.cb_gesdeutsch);
        }


  public void CheckboxUpload() {

        boolean cb_checked = ((CheckBox) cb_gesdeutsch).isChecked();
            if(cb_checked){
                Toast.makeText(AnghinzuActivity.this,"Checkbox is checked",Toast.LENGTH_SHORT).show();
                 String str_cb_gesdeutsch = "Yes";
        } else {
                Toast.makeText(AnghinzuActivity.this,"Checkbox is unchecked",Toast.LENGTH_SHORT).show();
                String str_cb_gesdeutsch = "No";
        }
    }


  public void OnAnghinzu(View view) {
    CheckboxUpload();
    String type = "add";
        BackgroundWorker backgroundWorker = new BackgroundWorker(this);
        backgroundWorker.execute(type, str_cb_gesdeutsch);
    
  }
}

BackgroundWorker.java

public class BackgroundWorker extends AsyncTask<String,Void,String> {

    Context context;
    AlertDialog alertDialog;
    BackgroundWorker(Context ctx) {
        context = ctx;
    }
  if(type.equals("add")) {
            try {
                String gesdeutsch = params[1];
                URL url = new URL("*******");
                HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setDoInput(true);
                OutputStream outputStream = httpURLConnection.getOutputStream();
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
                String post_data = URLEncoder.encode("Gesamtdeutschland", "UTF-8")+"="+URLEncoder.encode(gesdeutsch, "UTF-8");
                bufferedWriter.write(post_data);
                bufferedWriter.flush();
                bufferedWriter.close();
                outputStream.close();
                InputStream inputStream = httpURLConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));//iso-8859-1
                String result = "";
                String line = "";
                while((line = bufferedReader.readLine()) != null){
                    result += line;
                }
                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();
                return result;
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    protected void onPreExecute() {
        alertDialog = new AlertDialog.Builder(context).create();
        alertDialog.setTitle("Status");
    }

    @Override
    protected void onPostExecute(String result) {
        alertDialog.setMessage(result);
        alertDialog.show();
    }
}