This class retrieves JSON data from a PHP script and uses the data to populate a ListView using AsyncTasks. Any ideas on how to improve it?
public class MainActivity extends ActionBarActivity {
ArrayList<Location> arrayOfLocations;
LocationAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Construct the data source
arrayOfLocations = new ArrayList<Location>();
// Create the adapter to convert the array to views
adapter = new LocationAdapter(this, arrayOfLocations);
FillLocations myFill = new FillLocations();
myFill.execute();
}
//this class downloads an image and passes that (and other data) into an
//adapter which populates the ListView
class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> {
private int photoID = 1;
JSONObject json = null;
public BitmapWorkerTask(int photoID, JSONObject json) {
// Use a WeakReference to ensure the ImageView can be garbage
// collected
this.photoID = photoID;
this.json = json;
}
protected void onPreExecute() {
}
// Decode image in background.
@Override
protected Bitmap doInBackground(Integer... params) {
String initialURL = "http://afs.spotcontent.com/img/Places/Icons/";
final String updatedURL = initialURL + photoID + ".jpg";
Bitmap bitmap2 = null;
try {
bitmap2 = BitmapFactory.decodeStream((InputStream) new URL(
updatedURL).getContent());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return bitmap2;
}
// Once complete, see if ImageView is still around and set bitmap.
@Override
protected void onPostExecute(Bitmap bitmap2) {
try {
adapter.add(new Location(bitmap2, json.getString("PlaceTitle"),
json.getString("PlaceDetails"), json
.getString("PlaceDistance"), json
.getString("PlaceUpdatedTime")));
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
//this class retrieves the JSON data from the PHP script
//and parses it, then it calls the Bitmap task to get the
//image and then add the location
private class FillLocations extends AsyncTask<Integer, Void, String> {
protected void onPreExecute() {
}
// Decode image in background.
@Override
protected String doInBackground(Integer... params) {
String result = "";
InputStream isr = null;
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://myscript.php/"); // YOUR
// PHP
// SCRIPT
// ADDRESS
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
isr = entity.getContent();
// resultView.setText("connected");
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
// convert response to string
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(isr, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
isr.close();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
// parse json data
try {
JSONArray jArray = new JSONArray(result);
for (int i = 0; i < jArray.length(); i++) {
final JSONObject json = jArray.getJSONObject(i);
counter++;
try {
BitmapWorkerTask myTask = new BitmapWorkerTask(
json.getInt("ID"), json);
myTask.execute();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} catch (Exception e) {
// TODO: handle exception
Log.e("log_tag", "Error Parsing Data " + e.toString());
}
return msg;
}
protected void onPostExecute(String msg) {
// Attach the adapter to a ListView
ListView listView = (ListView) findViewById(R.id.listView1);
listView.setAdapter(adapter);
}
}
}
