使用 GSON 在 Volley 中发送参数

Question

我知道的 我可以在JsonObjectRequest 的帮助下使用Volley 而不使用GSON 来提出请求。现在我正在学习GSON，所以我可以在没有参数的情况下发出请求。

示例代码

    HashMap<String, String> params = new HashMap<String, String>();
        params.put("user",userId);

        Log.d(TAG + "pp", String.valueOf(params));




        String Url = Constants.Base_URL + "getcoupons/";

        JsonObjectRequest request = new JsonObjectRequest(Url,  new JSONObject(params),
                response -> {
                    Log.d(TAG, "respCoupan" + String.valueOf(response));

                    try {
                        String statusResponseObject = response.getString("status");
                        String msgObject = response.getString("msg");

                        if (statusResponseObject.equals("200")){

                            JSONArray jsonArray = response.getJSONArray("response");

                            for (int i = 0; i < jsonArray.length(); i++) {
                                JSONObject pendingFragResponse = jsonArray.getJSONObject(i);

                                String codeObject = pendingFragResponse.getString("code");
                                String typeObject = pendingFragResponse.getString("type");
                                String amountObject = pendingFragResponse.getString("amount");
                                String descriptionObject = pendingFragResponse.getString("description");
                                String leagueObject = pendingFragResponse.getString("league");
                                String expireObject = pendingFragResponse.getString("expire");

                                //

                                couponArrayList.add(new Coupon(codeObject, typeObject, amountObject,
                                        descriptionObject, leagueObject, expireObject));
                                couponAdapter = new CouponAdapter( couponArrayList, CoupanActivity.this);
                                recyclerView.setAdapter(couponAdapter);
                                wp10ProgressBar.hideProgressBar();
                                wp10ProgressBar.setVisibility(View.GONE);

                            }
                            couponAdapter.notifyDataSetChanged();
//                            wp10ProgressBar.hideProgressBar();
                        }else {
                            wp10ProgressBar.hideProgressBar();
                            wp10ProgressBar.setVisibility(View.GONE);
                            Toast.makeText(CoupanActivity.this, msgObject, Toast.LENGTH_SHORT).show();
                        }

                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(this, "Server didn't response, Try after some time", Toast.LENGTH_LONG).show();
                    }



                }, error -> {
            error.printStackTrace();
            Log.d(TAG + "error", String.valueOf(error.getMessage()));
            Toast.makeText(this, "Server didn't response, Try after some time", Toast.LENGTH_LONG).show();

        });

        MySingleton.getInstance(CoupanActivity.this).addToRequestQueue(request);

JSON

{
"status": "200",
"msg": "Successfully",
"response": [
    {
        "code": "YUDH20",
        "type": "Flat",
        "amount": "2",
        "description": "Flat 20% credit Discount",
        "league": "0",
        "league_name": "",
        "expire": "2019-08-22"
    }
]

}

我想要什么

我想要一个清晰的示例来使用 GSON 和参数发出请求（意味着使用 GSON 在请求中发送 Hashmap 值）。
我可以使用GSON 作为 java 类的参数吗？
如何将 GSON 用于标头？

Answer 1

您必须创建数据类“ModelClass”和ResponseClass gson 转换“ModelClass”中的数据，您可以简单地使用这个类：

      public class ModelClass {
       private String status;
       private String msg;
       private JSONArray response;
        ...

    }

并创建一个ResponseClass.class

    public class ResponseClass {
    private String code;
    private String type;
    private int amount;
    private String description;
    private String league;
    private String league_name;
    private String expire;
        ...

}

并将您的代码更改为：

  HashMap<String, String> params = new HashMap<String, String>();
        params.put("user", userId);

        Log.d(TAG + "pp", String.valueOf(params));


        String Url = SyncStateContract.Constants.Base_URL + "getcoupons/";

        JsonObjectRequest request = new JsonObjectRequest(Url, new JSONObject(params),
                response -> {
                    Log.d(TAG, "respCoupan" + String.valueOf(response));

                    try {

                        Gson gson = new GsonBuilder()
                                .serializeNulls()
                                .create();
                        Type type = new TypeToken<ModelClass>() {
                        }.getType();

                        ModelClass result = gson.fromJson(response.toString(), type);


                        if (result.getMsg().equals("200")) {
                            for (int i = 0; i < result.getResponse().size(); i++) {

                        result.getResponse().get(i).getAmount()
                        result.getResponse().get(i).getCode()
                        result.getResponse().get(i).getExpire()
                                ...
                        }}

                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(this, "Server didn't response, Try after some time", Toast.LENGTH_LONG).show();
                    }


                }, error -> {
            error.printStackTrace();
            Log.d(TAG + "error", String.valueOf(error.getMessage()));
            Toast.makeText(this, "Server didn't response, Try after some time", Toast.LENGTH_LONG).show();

        });

        MySingleton.getInstance(CoupanActivity.this).addToRequestQueue(request);