HTTP请求和线程

Question

First of all I apologize for my English.

I have 2 questions about this method would be responsible for making requests POST to a PHP server.

The first question is that I have an error and the application crash. First it was because I had to create a thread and put my logic inside, but now the APP closes without showing anything.

The second problem is that I don't know how to return as something in the thread. Should to write in a variable and then return that value. To show the code I put a fixed return true.

public boolean hacerPeticion(final String servicio, final Map params){
    new Thread(new Runnable()
    {
        @Override
        public void run()
        {
            String requestURL = R.string.http_base_url + servicio;

            try {
                HttpUtility.sendPostRequest(requestURL, params);
                String response = HttpUtility.readSingleLineRespone();

                JSONObject jsonObj = parsearJSON(response);

                if(jsonObj != null){
                    int error_code;
                    try {
                        error_code = Integer.parseInt(jsonObj.getString("error"));
                    } catch(NumberFormatException nfe) {
                        error_code = 99;
                    }

                    if(error_code == 0){
                        // true;
                    }else{
                        // false;
                    }
                }else{
                    // false;
                }
            } catch (IOException ex) {
                // false;
            } catch (JSONException e) {
                // false;
            }
            HttpUtility.disconnect();
        }
    }).start();

    return true;
}

Thanks!

Answer 1

First problem

You are completely ignoring your errors. Actually print the Exception so you can see what is going wrong.

catch (IOException ex) {
    ex.printStackTrace();
} 

---

Second problem

Your error is most likely coming from this line because R.string.http_base_url returns an int , not a String.

String requestURL = R.string.http_base_url + servicio;

To fix that specific problem, you need a Context to get the actual string value. For example, you could do something like this

String requestURL = getApplicationContext().getString(R.string.http_base_url) + servicio;

---

Third problem

You are using a low-level Thread instead of an AsyncTask (or some other network library like Volley or OkHttp which make network requests easy).

There is almost never a reason to use a Java Thread in Android code. Handler is the more correct class to use in that scenario, anyways.

---

Fourth problem

Since you are using asynchronous code, you can't simply expect a return value to comeback immediately. Your method will always return true (maybe before the Thread even starts).

The approach I recommend is to use a callback , like I've already answered before.

Answer 2

It sounds like you are talking about some kind of callback pattern. I guess the reason for the crash is you were blocking the UI thread causing the app to freeze , become unresponsive to the user. This is a guess as you only give a smigit of code. Implementing a callback or better yet use one built into the framework. If this is android onActivityResult is one example of a callback.