Using Google Books API in Android

Question

Hi I\'m new to Android and using web APIs. I\'m currently writing an application that can scan a barcode from a book and then search Google Books for it.

So far I i

Answer 1

I just finished doing this myself. This is how I implemented it using an HttpURLConnection and an AsyncTask (I just call "https://www.googleapis.com/books/v1/volumes?q=isbn:"+yourISBN and parse the JSON):

// Received ISBN from Barcode Scanner. Send to GoogleBooks to obtain book information.
class GoogleApiRequest extends AsyncTask{

    @Override
    protected void onPreExecute() {
        // Check network connection.
        if(isNetworkConnected() == false){
            // Cancel request.
            Log.i(getClass().getName(), "Not connected to the internet");
            cancel(true);
            return;
        }
    }
    @Override
    protected JSONObject doInBackground(String... isbns) {
        // Stop if cancelled
        if(isCancelled()){
            return null;
        }

        String apiUrlString = "https://www.googleapis.com/books/v1/volumes?q=isbn:" + isbns[0];
        try{
            HttpURLConnection connection = null;
            // Build Connection.
            try{
                URL url = new URL(apiUrlString);
                connection = (HttpURLConnection) url.openConnection();
                connection.setRequestMethod("GET");
                connection.setReadTimeout(5000); // 5 seconds
                connection.setConnectTimeout(5000); // 5 seconds
            } catch (MalformedURLException e) {
                // Impossible: The only two URLs used in the app are taken from string resources.
                e.printStackTrace();
            } catch (ProtocolException e) {
                // Impossible: "GET" is a perfectly valid request method.
                e.printStackTrace();
            }
            int responseCode = connection.getResponseCode();
            if(responseCode != 200){
                Log.w(getClass().getName(), "GoogleBooksAPI request failed. Response Code: " + responseCode);
                connection.disconnect();
                return null;
            }

            // Read data from response.
            StringBuilder builder = new StringBuilder();
            BufferedReader responseReader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String line = responseReader.readLine();
            while (line != null){
                builder.append(line);
                line = responseReader.readLine();
            }
            String responseString = builder.toString();
            Log.d(getClass().getName(), "Response String: " + responseString);
            JSONObject responseJson = new JSONObject(responseString);
            // Close connection and return response code.
            connection.disconnect();
            return responseJson;
        } catch (SocketTimeoutException e) {
            Log.w(getClass().getName(), "Connection timed out. Returning null");
            return null;
        } catch(IOException e){
            Log.d(getClass().getName(), "IOException when connecting to Google Books API.");
            e.printStackTrace();
            return null;
        } catch (JSONException e) {
            Log.d(getClass().getName(), "JSONException when connecting to Google Books API.");
            e.printStackTrace();
            return null;
        }
    }
    @Override
    protected void onPostExecute(JSONObject responseJson) {
        if(isCancelled()){
            // Request was cancelled due to no network connection.
            showNetworkDialog();
        } else if(responseJson == null){
            showSimpleDialog(getResources().getString(R.string.dialog_null_response));
        }
        else{
            // All went well. Do something with your new JSONObject.
        }
    }
}

protected boolean isNetworkConnected(){

    // Instantiate mConnectivityManager if necessary
    if(mConnectivityManager == null){
        mConnectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    }
    // Is device connected to the Internet?
    NetworkInfo networkInfo = mConnectivityManager.getActiveNetworkInfo();
    if(networkInfo != null && networkInfo.isConnected()){
        return true;
    } else {
        return false;
    }
}

I've omitted the code for my dialog methods as they are not relevant. Hope this helps.