Android Volley JsonObject放置过程

Question

在数据库textview中拉数据 要打印。但值是空的。
请求处理中是否有错误？或请求过程应该如何？ php中有错误吗？ 下面是我的android和php代码。

    userTc = findViewById(R.id.tc_no);
    userName = findViewById(R.id.name);
    userSurname = findViewById(R.id.surname);
    userType = findViewById(R.id.type);

    JSONObject jsonObject=new JSONObject();
    try {
        jsonObject.put("tc",userTc);


    } catch (JSONException e) {
        e.printStackTrace();
    }

    final String url = "http:/database/show.php";
    JsonObjectRequest jsonObjectRequest = new JsonObjectRequest
            (Request.Method.GET, url, jsonObject, new 
    Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                        userTc.setText(response.getString("tc"));
                        userName.setText(response.getString("name"));
                        userSurname.setText(response.getString("surname"));
                        userType.setText(response.getString("type"));
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(getApplicationContext(), "error" + error, 
            Toast.LENGTH_SHORT).show();
                }
            });{

    }








    $tc=$_GET["tc"];
    $sql=$conn->prepare("SELECT tc,name,surname,type FROM personel");
    $sql->execute();
    $fetch=$sql->fetch(PDO::FETCH_ASSOC);
    echo json_encode(array("tc"=>$fetch["tc"],"name"=>$fetch["name"],"surname"=>$fetch["surname"],"type"=>$fetch["type"]));