如何使用php将适配器上的字符串解析为数据库

Question

嗨，我是新来的人，在我的android编程中有些卡住了，我无法使用php将购物车列表中的数据插入数据库。

pro.php

<?php require_once 'connect1.php'; if ($_SERVER['REQUEST_METHOD'] =='POST'){

$products = $_POST['products'];

$decoded = json_decode($products, true);

for($i = 0; $i < sizeof($decoded); $i = $i + 1) {
    $sql = "INSERT INTO product_table (product, price) VALUES (\"".$decoded[$i]['product']."\", ".$decoded[$i]['price'] .")";
    if ( mysqli_query($conn, $sql) ) {
        $result["success"] = "1";
        $result["message"] = "success";
    } else {

        $result["success"] = "0";
        $result["message"] = mysqli_error($conn);
        break;
    }

    mysqli_close($conn);
}

echo json_encode($result);}?>

我的json： krnjfrag.class

private void placeorder() {
    final ProgressDialog pDial = new ProgressDialog(getActivity());
    pDial.setMessage("Loading...");
    pDial.show();

    Map<String,String> params = new HashMap<>();
    params.put("product", String.valueOf(title));
    params.put("price", String.valueOf(price));

    JSONObject parameters = new JSONObject();
    JSONArray products = new JSONArray();
    for(Product p:example){
        JSONObject prod = new JSONObject();
        try {
            prod.put("product",p.getTitle());
            prod.put("price",p.getPrice());
            products.put(prod);
            parameters.put("products",products);
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

   JsonObjectRequest keranjang = new JsonObjectRequest(Request.Method.POST,URL_pesan,parameters,  new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response)
        {
            System.out.println();
            try{
                String success = response.getString("success");
                    /*Intent intent = new Intent(getActivity(),CheckfinalActivity.class);
                    intent.putExtra("product", title);
                    intent.putExtra("price",price);
                    startActivity(intent);
                    String title = response.getString("product");
                    String price = response.getString("price");*/
                Toast.makeText(getActivity(), "Tersimpan", Toast.LENGTH_SHORT).show();
                madapter.notifyDataSetChanged();
                pDial.dismiss();
                    /*Product product = new Product();
                    product.setTitle(jsonObject.getString("product"));
                    product.setPrice(jsonObject.getDouble("price"));
                    example.add(product);
                    total.setText((int) jsonObject.getDouble("total"));*/
            } catch (JSONException e) {
                e.printStackTrace();
                Toast.makeText(getActivity(), "Gagal", Toast.LENGTH_SHORT).show();
            }
        }
   },new Response.ErrorListener() {
       @Override
       public void onErrorResponse(VolleyError error) {
           error.printStackTrace();
           Toast.makeText(getActivity(), "Tidak dapat menyimpan", Toast.LENGTH_SHORT).show();
           pDial.dismiss();
       }
   });
    Volley.newRequestQueue(getActivity()).add(keranjang);

}

我只希望可以将recyclerview上的数据插入数据库，因此，如果我在管理员端打开，我可以知道用户想购买哪个。

我总是在解析错误时出错