What is the most efficient way on Android to call

问题:

I'm the perfectionist type, I already got web API calls working fine with Google Places API (just as an example), but I feel it's sometimes slow or maybe I'm not doing it right. Some blogs are saying I should use AndroidHttpClient, but I'm not, should I ?

The web API calls i'm using return json and I don't run them on the UI thread, hence using AsyncTask (is AsyncTask the most efficient way to run on background thread or should I use something else ?)

Please see my code and tell me how could it be more efficient in anyway

public static class NearbySearchRequest extends AsyncTask<String, Void, JSONObject>
{
    Exception mException = null;

    @Override
    protected void onPreExecute()
    {
        super.onPreExecute();
        this.mException = null;
    }

    @Override
    protected JSONObject doInBackground(String... params)
    {
        StringBuilder urlString = new StringBuilder();
        urlString.append("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
        urlString.append("key=").append(Constants.GOOGLE_SIMPLE_API_KEY);
        urlString.append("&location=").append(params[0]);
        urlString.append("&sensor=").append("true");
        urlString.append("&language=").append("en-GB");
        urlString.append("&name=").append(params[1]);
        urlString.append("&rankby=").append("distance");

        LogHelper.Log(urlString.toString());

        HttpURLConnection urlConnection = null;
        URL url = null;
        JSONObject object = null;

        try
        {
            url = new URL(urlString.toString());
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.setDoOutput(true);
            urlConnection.setDoInput(true);
            urlConnection.connect();
            InputStream inStream = null;
            inStream = urlConnection.getInputStream();
            BufferedReader bReader = new BufferedReader(new InputStreamReader(inStream));
            String temp, response = "";
            while ((temp = bReader.readLine()) != null)
                response += temp;
            bReader.close();
            inStream.close();
            urlConnection.disconnect();
            object = (JSONObject) new JSONTokener(response).nextValue();
        }
        catch (Exception e)
        {
            this.mException = e;
        }

        return (object);
    }

    @Override
    protected void onPostExecute(JSONObject result)
    {
        super.onPostExecute(result);

        if (this.mException != null)
            ErrorHelper.report(this.mException, "Error # NearbySearchRequest");
    }
}

回答1:

The Http engine you're using seems the best choice. Actually any other 3-rd party engines are based either on Apache, either on HttpUrlConnection. I prefer to use Spring for Android as that API provide an abstraction over Http Engine and you don't really need to care how about what API to use based on API level. Or you can use Volley - a very fashionable library.

I would touch however some of your code:

1. What if there is an exception while reading the stream? Then the stream remains open and also the connection. So I would suggest to have a finally block where the streams and connection is closed no matter if you get an exception or not:

   HttpURLConnection urlConnection = null;
   URL url = null;
   JSONObject object = null;
   InputStream inStream = null;
   try {
       url = new URL(urlString.toString());
       urlConnection = (HttpURLConnection) url.openConnection();
       urlConnection.setRequestMethod("GET");
       urlConnection.setDoOutput(true);
       urlConnection.setDoInput(true);
       urlConnection.connect();
       inStream = urlConnection.getInputStream();
       BufferedReader bReader = new BufferedReader(new InputStreamReader(inStream));
       String temp, response = "";
       while ((temp = bReader.readLine()) != null) {
           response += temp;
       }
       object = (JSONObject) new JSONTokener(response).nextValue();
   } catch (Exception e) {
       this.mException = e;
   } finally {
       if (inStream != null) {
           try {
               // this will close the bReader as well
               inStream.close();
           } catch (IOException ignored) {
           }
       }
       if (urlConnection != null) {
           urlConnection.disconnect();
       }
   }
   

2. JSON parsing: you're using the Android standard way of parsing JSON, but that's not the fastest and easiest to work with. GSON and Jackson are better to use. To make a comparison when it comes for JSON parsers, I would go for Jackson. Here's another SO topic on this comparison.

3. Don't concatenate strings like that as concatenating strings will create each time another string. Use a StringBuilder instead.

4. Exception handling (this is anyway a long-debate subject in all programming forums). First of all you have to log it (Use Log class not System.out.printXXX). Then you need to either inform the user: either you toast a message, either you show a label or notification. The decision depends on the user case and how relevant is the call you're making.

These are the topics I see in you code.

EDIT I realize I didn't answer this: is AsyncTask the most efficient way to run on background thread or should I use something else?

The short answer I would give is: if you're supposed to perform a short time lived request, then AsyncTask is perfect. However, if you need to get some data and display it - but you don't want to worry about whether to download again if the screen is rotated and so on, I would strongly recommend using an AsyncTaskLoader and Loaders in general.

If you need to download some big data, then either you use an IntentService or, for heavy-weight operations, DownloadManager.

Enjoy coding!

回答2:

------Create a Service Handler Class to your Project--------

public class ServiceHandler {

static String response = null;
public final static int GET = 1;
public final static int POST = 2;

public ServiceHandler() {
}

/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * */
public String makeServiceCall(String url, int method) {
    return this.makeServiceCall(url, method, null);
}

/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * @params - http request params
 * */
public String makeServiceCall(String url, int method,
        List<NameValuePair> params) {
    try {
        // http client
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpEntity httpEntity = null;
        HttpResponse httpResponse = null;

        // Checking http request method type
        if (method == POST) {
            Log.e("in POST","in POST");
            HttpPost httpPost = new HttpPost(url);
            // adding post params
            if (params != null) {
                Log.e("in POST params","in POST params");
                httpPost.setEntity(new UrlEncodedFormEntity(params));
            }
            Log.e("url in post service",url);
            httpResponse = httpClient.execute(httpPost);

        } else if (method == GET) {
            // appending params to url
            Log.e("in GET","in GET");
            if (params != null) {
                Log.e("in GET params","in GET params");
                String paramString = URLEncodedUtils
                        .format(params, "utf-8");
                url += "?" + paramString;
            }
            Log.e("url in get service",url);
            HttpGet httpGet = new HttpGet(url);

            httpResponse = httpClient.execute(httpGet);

        }
        httpEntity = httpResponse.getEntity();
        response = EntityUtils.toString(httpEntity);

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    return response;

}
public String makeServiceCallIMAGE(String url, int method,
        List<NameValuePair> params) {
    try {
        // http client
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpEntity httpEntity = null;
        HttpResponse httpResponse = null;

        // Checking http request method type
        if (method == POST) {
            HttpPost httpPost = new HttpPost(url);
            // adding post params
            if (params != null) {
                httpPost.setEntity(new UrlEncodedFormEntity(params));

            }

            httpResponse = httpClient.execute(httpPost);

        } else if (method == GET) {
            // appending params to url
            if (params != null) {
                String paramString = URLEncodedUtils
                        .format(params, "utf-8");
                url += "?" + paramString;
            }
            HttpGet httpGet = new HttpGet(url);

            httpResponse = httpClient.execute(httpGet);

        }
        httpEntity = httpResponse.getEntity();
        response = EntityUtils.toString(httpEntity);

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return response;
}
}

--------------AsyncTask For Login------------------

public class Login_Activity extends ActionBarActivity {

//Internet Service
NetworkConnection nw;
ProgressDialog prgDialog;
Boolean netConnection = false;
//

//Login API
String loginURL ="url";
//

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    nw = new NetworkConnection(getApplicationContext());
    prgDialog = new ProgressDialog(this);
    // Set Cancelable as False
    prgDialog.setCancelable(false);

    new LoginOperation().execute();
}

private class LoginOperation  extends AsyncTask<String, Void, Void> {

    String status, message;
    @Override
    protected void onPreExecute() {
        // Set Progress Dialog Text
        prgDialog.setMessage("Logging...");
        prgDialog.show();
    }

    @Override
    protected Void doInBackground(String... urls) {

        if(nw.isConnectingToInternet() == true)
        {
            try
            {
                List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
                nameValuePairs.add(new BasicNameValuePair("method", "ClientesLogin"));
                nameValuePairs.add(new BasicNameValuePair("Email", str_Email));
                nameValuePairs.add(new BasicNameValuePair("Senha", str_Password));
                ServiceHandler sh  = new ServiceHandler();
                String response = sh.makeServiceCall(loginURL, ServiceHandler.GET,
                        nameValuePairs);

                Log.e("response", response);

                JSONObject js = new JSONObject(response);
                status = js.getString("status");
                Log.e("status",status);

                if(status.contains("Fail"))
                {
                    message = js.getString("message");
                }
                /*else
                {
                    JSONObject jslogin=js.getJSONObject("user_list");
                    for (int i = 0; i < jslogin.length(); i++) {
                    }
                }*/

            }catch(Exception ex){

            }
            netConnection = true;
        }else
        {
            netConnection = false;
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        prgDialog.dismiss();

        if(netConnection == false)
        {
            Toast toast = Toast.makeText(getApplicationContext(),"Internet is not available. Please turn on and try again.", Toast.LENGTH_LONG);
            toast.setGravity(Gravity.CENTER, 0, 0);
            toast.show();
        }
        else
        {
            if(status.contains("Success"))
            {
                Toast toast = Toast.makeText(getApplicationContext(), "Login Successful", Toast.LENGTH_SHORT);
                toast.setGravity(Gravity.CENTER, 0, 0);
                toast.show();

                Intent i=new Intent(Login_Activity.this,home_page_activity.class);
                startActivity(i);
            }
            else{
                Toast toast = Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT);
                toast.setGravity(Gravity.CENTER, 0, 0);
                toast.show();
            }
        }
        super.onPostExecute(result);
    }
}
}

---------------Network Connection class---------------------

public class NetworkConnection {

Context context;

public NetworkConnection(Context context){
    this.context = context;
}

public boolean isConnectingToInternet(){
    ConnectivityManager connectivity = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
      if (connectivity != null) 
      {
          NetworkInfo[] info = connectivity.getAllNetworkInfo();
          if (info != null) 
              for (int i = 0; i < info.length; i++) 
                  if (info[i].getState() == NetworkInfo.State.CONNECTED)
                  {
                      return true;
                  }
      }
      return false;
}
}

---

JSONArray main1 = js.getJSONArray("Test 1");

  for (int i = 0; i < main1.length(); i++) {

    JSONObject jsonObject = main1.getJSONObject(i);