凌空：JsonObjectRequest中的onResponse延迟请求

Question

Am a newbie to the Volley library, I'm creating a simple Android app that takes data from an API that generates in JSON. After debugging, only this particular function fetchAccD mentioned below have delay issues with Android Volley. Other functions within this Activity and other Activities which implies the JsonObjectRequest works perfectly fine.

{
    "Account": {
        "remarks": "NIL"
        "uname": "admin"
        "pword": null // value not to be shown
        "key": 1316451
        "name": "msummons sudo"
    }
}

Here's my current code

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dashboard);
    uName = getIntent().getStringExtra("username");
    // reset session
    authidCoDe = 0;

    // invoke session
    Account account = fetchAccD(uName);

    if (account != null) {
        authidCoDe = account.getKey();
        ...


// init user details before loading
private final Account fetchAccD (String userN) {
    final Account account = new Account();
    requestQueue = null;
    requestQueue = Volley.newRequestQueue(this);
    String urlConstruct = *json url*;

    JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, urlConstruct,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                        JSONArray jsonArray = response.getJSONArray("Account");
                        JSONObject jsonObject = jsonArray.getJSONObject(0);
                        account.setUname(jsonObject.optString("uname"));
                     // account.setPword(jsonObject.optString("pword"));
                        account.setKey(jsonObject.optInt("key"));
                        account.setName(jsonObject.optString("name"));
                        account.setRemarks(jsonObject.optString("remarks"));
                        requestQueue.stop();
                    }
                    catch (JSONException e) {
                        Toast.makeText(getApplicationContext(), "Fetch failed!", Toast.LENGTH_SHORT).show();
                        requestQueue.stop();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Toast.makeText(getApplicationContext(), "Fetch failed!", Toast.LENGTH_SHORT).show();
            requestQueue.stop();
        }
    });
    requestQueue.add(jsonObjectRequest);
    return account;
}

When invoking fetchAccD , the code runs perfect up to

JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, urlConstruct,
        new Response.Listener<JSONObject>()

Then it proceeds to onCreate where it runs after the fetchAccD method

if (account != null) {
    authidCoDe = account.getKey();
    ...

Before it goes back to the rest of the onResponse method in the fetchAccD method.

@Override
public void onResponse(JSONObject response) {
    try {
        JSONArray jsonArray = response.getJSONArray("Account");
        ...

I've used JsonObjectRequest GET for most of my functions to fetch JSON, this problem only happens just for the fetchAccD function. Thanks!

Answer 1

onResponse is asynchronous, it will be invoked when the server returns a response.

So you should wait the response before doing this:

if (account != null) {
    authidCoDe = account.getKey();
    ...
}

---

onCreate should do:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dashboard);
    uName = getIntent().getStringExtra("username");
    // reset session
    authidCoDe = 0;

    // invoke session
    fetchAccD(uName);
}

In onResponse you can do:

public void onResponse(JSONObject response) {

    try {
        JSONArray jsonArray = response.getJSONArray("Account");
        JSONObject jsonObject = jsonArray.getJSONObject(0);
        account.setUname(jsonObject.optString("uname"));
     // account.setPword(jsonObject.optString("pword"));
        account.setKey(jsonObject.optInt("key"));
        account.setName(jsonObject.optString("name"));
        account.setRemarks(jsonObject.optString("remarks"));
        useAccount(account);
        requestQueue.stop();
    }
    catch (JSONException e) {
        Toast.makeText(getApplicationContext(), "Fetch failed!", Toast.LENGTH_SHORT).show();
        requestQueue.stop();
    }
}

Define a method useAccount :

private void useAccount(Account account) {
    if (account != null) {
        authidCoDe = account.getKey();
        ...
    }
}

And fetchAccD does not need to return a value, you can make it void .