android http post asynctask

Question

Please can anyone tell me how to make an http post to work in the background with AsyncTask and how to pass the parameters to the AsyncTask? All the examples that I found were not clear enough for me and they were about downloading a file.

I'm running this code in my main activity and my problem is when the code sends the info to the server the app slows down as if it is frozen for 2 to 3 sec's then it continues to work fine until the next send. This http post sends four variables to the server (book, libadd, and time) the fourth is fixed (name)

Thanks in advance

    public void  SticketFunction(double book, double libadd, long time){
        Log.v("log_tag", "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% SticketFunction()");
        //HttpClient
        HttpClient nnSticket = new DefaultHttpClient();
        //Response handler
        ResponseHandler<String> res = new BasicResponseHandler();

        HttpPost postMethod = new HttpPost("http://www.books-something.com");


        try {
            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(5);

            nameValuePairs.add(new BasicNameValuePair("book", book+""));

            nameValuePairs.add(new BasicNameValuePair("libAss", libass+""));

            nameValuePairs.add(new BasicNameValuePair("Time", time+""));

            nameValuePairs.add(new BasicNameValuePair("name", "jack"));
            //Encode and set entity
            postMethod.setEntity(new UrlEncodedFormEntity(nameValuePairs, HTTP.UTF_8));
            //Execute 
            //manSticket.execute(postMethod);
            String response =Sticket.execute(postMethod, res).replaceAll("<(.|\n)*?>","");
            if (response.equals("Done")){

                //Log.v("log_tag", "!!!!!!!!!!!!!!!!!! SticketFunction got a DONE!");

            }
            else Log.v("log_tag", "!!!!!!!?????????? SticketFunction Bad or no response: " + response);

        } catch (ClientProtocolException e) {  
            // TODO Auto-generated catch block 
            //Log.v("log_tag", "???????????????????? SticketFunction Client Exception");
        } catch (IOException e) {  
            // TODO Auto-generated catch block
            //Log.v("log_tag", "???????????????????? IO Exception");
        } 
    }

}

Mitsuaki Ishimoto · Answer 1 · 2016-02-01T13:05:58.987

At first, You put a class like following:

public class AsyncHttpPost extends AsyncTask<String, String, String> {
    interface Listener {
        void onResult(String result);
    }
    private Listener mListener;
    private HashMap<String, String> mData = null;// post data

    /**
     * constructor
     */
    public AsyncHttpPost(HashMap<String, String> data) {
        mData = data;
    }
    public void setListener(Listener listener) {
        mListener = listener;
    }

    /**
     * background
     */
    @Override
    protected String doInBackground(String... params) {
        byte[] result = null;
        String str = "";
        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost(params[0]);// in this case, params[0] is URL
        try {
            // set up post data
            ArrayList<NameValuePair> nameValuePair = new ArrayList<NameValuePair>();
            Iterator<String> it = mData.keySet().iterator();
            while (it.hasNext()) {
                String key = it.next();
                nameValuePair.add(new BasicNameValuePair(key, mData.get(key)));
            }

            post.setEntity(new UrlEncodedFormEntity(nameValuePair, "UTF-8"));
            HttpResponse response = client.execute(post);
            StatusLine statusLine = response.getStatusLine();
            if(statusLine.getStatusCode() == HttpURLConnection.HTTP_OK){
                result = EntityUtils.toByteArray(response.getEntity());
                str = new String(result, "UTF-8");
            }
        }
        catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        catch (Exception e) {
        }
        return str;
    }

    /**
     * on getting result
     */
    @Override
    protected void onPostExecute(String result) {
        // something...
        if (mListener != null) {
            mListener.onResult(result)
        }
    }
}

Now. You just write some lines like following:

HashMap<String, String> data = new HashMap<String, String>();
data.put("key1", "value1");
data.put("key2", "value2");
AsyncHttpPost asyncHttpPost = new AsyncHttpPost(data);
asyncHttpPost.setListener(new AsyncHttpPost.Listener(){
    @Override
    public void onResult(String result) {
        // do something, using return value from network
    }
});
asyncHttpPost.execute("http://example.com");

great solution! drop in your project in a java file and go. most painless way i've seen to do async posts. — StanleyZheng, Mar 10 '14 at 15:43
How to access result in the class has instance of AsyncHttpPost ? — yatanadam, Jul 26 '14 at 22:24
Work like charm thx, i have been following different examples her and there, this is the best one so far and it works thank you. — Maytham Fahmi, Apr 04 '15 at 17:58
Android 6.0 removes HttpClient, You should now use HttpURLConnection instead. — Pete, Jul 30 '16 at 14:54

score 3 · Answer 2 · answered Oct 22 '11 at 15:42

3

First i would not recommend do a Http request in a AsyncTask, you better try a Service instead. Going back to the issue on how to pass parameter into an AsyncTask when you declared it you can defined each Object class of the AsyncTask like this.

public AsyncTask <Params,Progress,Result> {

}

so in your task you should go like this

public MyTask extends<String,Void,Void>{

public Void doInBackground(String... params){//those Params are String because it's declared like that

}

}

To use it, it's quite simple

new MyTask().execute("param1","param2","param3")

answered Oct 22 '11 at 15:42

Necronet

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What is a a Service, and why do you recommend that instead? – aanders77 Nov 23 '12 at 13:00
There is plenty information regarding Servicec, the main difference is that a Service is not attach to an Activity, runs in background but still in the main Thread, there is another flavor of Service called IntentService which has a method that run in another Thread. Depends on the case I try to use Service whenever I do a Http request. – Necronet Nov 25 '12 at 16:58
Ok, but WHY do you prefer a service? Is it safer, quicker, easier or ?? – aanders77 Nov 25 '12 at 20:50
1

One of the main reason is that Async task are activity dependant this mean that one Task cannot leave without a context attach to it once the activity is finish() the task also will be remove, meaning that your HttpCalled may have succeed it or not but you just wasted user resources in something that you wont even use; as for the service you have to explicitly destroy it with stopSelf or stopService or unbind it from every context in order to do it so is safer. For more about this go to http://www.youtube.com/watch?v=xHXn3Kg2IQE – Necronet Nov 26 '12 at 09:39

android http post asynctask

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