This class causing me android.os.NetworkOnMainThreadException,i know that i have to use asyncTask to make it but i can't figure out how because i am using 1 fragments and this make my application very slow especially when i laod bitmaps, can any one help me please.
public class ContainerData {
static public Context context;
public ContainerData() {
}
public static ArrayList<Feed> getFeeds(String feedurl){
SAXParserFactory fabrique = SAXParserFactory.newInstance();
SAXParser parseur = null;
ArrayList<Feed> feeds = null;
try {
parseur = fabrique.newSAXParser();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
}
URL url = null;
try {
url = new URL(feedurl);
} catch (MalformedURLException e1) {
e1.printStackTrace();
}
DefaultHandler handler = new ParserXMLHandler();
try {
parseur.parse(url.openConnection().getInputStream(), handler);
feeds = ((ParserXMLHandler) handler).getData();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return feeds;
}
}
If you use AsyncTask make sure getFeeds is called inside the doInBackground(...) callback
Regardless of whether you use a fragment or not, you're still trying to perform Network activity on the main thread.
Create a generic class that extends AsyncTask which can perform all your parsing.
public class MyTaskHandler extends AsyncTask<String, Integer, Boolean>
{
#Override
protected void onPreExecute()
{
//Could display progress dialog here
}
#Override
protected Boolean doInBackground(String... params)
{
//Implement your parser here
}
#Override
protected void onPostExecute(Boolean result)
{
//Check result, dismiss dialog etc
}
}
Then create a new instance of MyTaskHandler and run it...
MyTaskHandler myTask = new MyTaskHandler();
myTask.execute("http://www.myxmlsite.com/lists.xml");
The execute method can take (String... params) so you can pass for example a URL,and retrieve it in doInBackground(String... params)
#Override
protected Boolean doInBackground(String... params)
{
//Implement your parser here
String urlToParse = params[0];
}
Best of luck.
Related
If I have an AsyncTask as a separate class, and I run the AsyncTask from an Activity, will the AsyncTask hold reference to the Activity , just like if it were an inner class of the later?
Or does it solve the issue of memory leak?
Also, will passing the context wrapped up in a WeakReference to the AsyncTask make any change?
you can use like this and get the refrense of activity
public class DeleteUserTask extends AsyncTask<String, String, String> {
private Context context;
private JSONObject Object, Object1;
public static String Success, Exception;
public static boolean isClick;
public DeleteUserTask(Context ctx) {
context = ctx;
}
#Override
protected void onPreExecute() {
OrganizationUser_EditProfileScreen.pb.setVisibility(View.VISIBLE);
}
#Override
protected String doInBackground(String... params) {
try {
ActivityBase.result = null;
Log.e("", "Request-->" + writeJSON().toString());
ActivityBase.PostMethod(context,
WebServiceLinks.UserStatusButtonTask, writeJSON());
Object = new JSONObject(ActivityBase.result);
Object1 = Object
.getJSONObject("OrganizationUserProfileButtonUpdateResult");
Success = Object1.getString("Success");
Exception = Object1.getString("Exception");
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
try {
OrganizationUser_EditProfileScreen.pb.setVisibility(View.GONE);
if (ActivityBase.result != null && Success == "true") {
ActivityBase
.GeneralDialog(R.string.account, Exception, context);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public JSONObject writeJSON() {
JSONObject object = new JSONObject();
try {
object.put("OrgID", OrganizationLoginTask.OrgID);
object.put("OrgUserID", Search_Screen.OrgUserID);
object.put("Status", OrganizationUser_EditProfileScreen.Status);
object.put("ModifiedByTypeCode", "2");
object.put("ModifiedSourceCode", "8");
} catch (Exception e) {
e.printStackTrace();
}
return object;
}
}
Hello so I have already an expirience with AsyncTask so I can manage to get some data with PHP scripts from an SQL Server and parsed them with JSON. Now what I would want is to know how can I use the AsyncTask in order to load images to some activities. Also is there anyway that I can call the AsyncTask before the app starts? because that would be really helpful too.
I don't have any adapters I am just using this for the AsyncTask:
// The definition of our task class
private class PostTask extends AsyncTask<String, Integer, String> {
private String postName;
private JSONObject jsonvar = new JSONObject();
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
this.postName = params[0];
String status = "";
List<NameValuePair> values = new ArrayList<NameValuePair>();
values.add( new BasicNameValuePair( "username", this.postName ) );
final AndroidHttpClient client = AndroidHttpClient.newInstance( "" );
HttpResponse response = HttpHelper.postResponse( client, Register.phpUrl, values );
String data = HttpHelper.getData( response );
try {
jsonvar = new JSONObject(data);
status=jsonvar.getString("status");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
client.close();
return status;
}
// #Override
// protected void onProgressUpdate(Integer... values) {
// super.onProgressUpdate(values);
// }
#Override
protected void onPostExecute(String status) {
String session = "", status_message = " ";
try {
status_message = jsonvar.getString("status_message");
} catch (JSONException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
super.onPostExecute(status);
}
}
}
As i can tell with information provided, supposing that what you read from your server is the image URL and obtain it in JSON format, what i would do is writing a listener to your AsyncTask, calling it in onPostExecute method, and loading it in your Activity using PicassoImagesLoader
Something like:
private class PostTask extends AsyncTask<String, Integer, String> {
public interface onLoadFinishedListener {
public void onLoadFinished(JSONObject response)
}
protected JSONObject onPostExecute(JSONObject response){
onLoadFinished(response);
}
}
And in your Activity:
public myActivity extends Activity implements PostTask.onLoadFinishedListener {
#Override
onLoadFinished(JSONObject response){
Picasso.with(this).load(response.getString("url")).into(imageView);
}
}
Something like this would help :)
This is my first async task, which gets called first, it gets data from server and then onPostExecute it executes other async task, which downloads and sets image.
private class GetData extends AsyncTask<String, Void, Void> {
private final HttpClient client = new DefaultHttpClient();
private String content;
private String error = null;
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... progress) {
}
#Override
protected Void doInBackground(String... params) {
try {
HttpGet httpget = new HttpGet(params[0]);
ResponseHandler<String> responseHandler = new BasicResponseHandler();
content = client.execute(httpget, responseHandler);
} catch (ClientProtocolException e) {
error = e.getMessage();
cancel(true);
} catch (IOException e) {
error = e.getMessage();
cancel(true);
}
return null;
}
#Override
protected void onPostExecute(Void result) {
if (error == null) {
try {
JSONObject dataDishes = new JSONObject(content);
Log.d("DISHES", dataDishes.toString());
ArrayList<DishModel> dishData = new ArrayList<DishModel>();
for (int i = 0; i < 8; i++) {
DishModel model = new DishModel();
model.setName("Company " + i);
model.setDesc("desc" + i);
//TODO: set data img
new GetImage(model).execute("http://example.com/" + (i + 1) + ".png");
dishData.add(model);
}
ListView listAllDishes = (ListView) getView().findViewById(R.id.listView);
DishRowAdapter adapterAllDishes = new DishRowAdapter(getActivity(),
R.layout.dish_row, dishData);
listAllDishes.setAdapter(adapterAllDishes);
} catch (JSONException e) {
Log.d("DISHES", e.toString());
}
} else {
Log.e("DISHES", error);
}
}
}
This is another async task, it downloads image and onPostExecute it sets image to passed model.
private class GetImage extends AsyncTask<String, Void, Void> {
private DishModel model;
private Bitmap bmp;
public getImage(DishModel model) {
this.model = model;
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... progress) {
}
#Override
protected Void doInBackground(String... params) {
try {
URL url = new URL(params[0]);
Log.d("DISHES", params[0]);
try {
bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
} catch (IOException e) {
Log.d("DISHES", e.toString());
}
} catch (MalformedURLException e) {
Log.d("DISHES", e.toString());
}
return null;
}
#Override
protected void onPostExecute(Void result) {
model.setPhoto(bmp);
}
}
It works if I do both data/image download proccess in one AsyncTask doInBackground(String... params), but it doesnt when I split data and image downloading into seperate async tasks. Furthermore I dont get any exceptions or errors.
UPDATE: Images shows up when i switch views..
At first, getImage and getData are classes, and classes names in Java are capitalized.
Technically, you can run another AsyncTask from onProgressUpdate() or onPostExecute() - https://stackoverflow.com/a/5780190/1159507
So, try to put the breakpoint in second AsyncTask call and debug is it called.
I want to start an AsyncTask inside another AsyncTask.
I'm trying to do this by starting the second AsyncTask in 'onPostExecute' of the first AsyncTask. The result is that the second AsyncTask starts after the first has finished.
How can I solve this?
Thank you
here's the code
private class Parse extends AsyncTask<Void, Void, Void>{
Document doc = null;
Element son = null;
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected Void doInBackground(Void... params) {
try {
doc = Jsoup.connect("MY_URL").get();
son= doc.body();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
for(CONDITION){
//MY_CODE
new DownloadImageTask().execute();
}
}
}
This is the second AsyncTask
private class DownloadImageTask extends AsyncTask<String, Void, String> {
Bitmap bitmap;
ImageView image = new ImageView(Events.this);
#Override
protected void onPreExecute() {
};
protected String doInBackground(String... urls) {
try {
URL url = new URL("MY_URL");
bitmap = BitmapFactory.decodeStream(url.openConnection().getInputStream());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
First, please refer to the oficial documentation to have a best understanding about AsyncTask: http://developer.android.com/reference/android/os/AsyncTask.html
The onPostExecute runs in the main thread, after the background task finishes. This method is designed this way to be used to comunicate with the UI thread to handle the execution.
If you want to run the second AsyncTask with your background code, or just after it started, you have to do this on the doInBackground method.
I can't explain why onPostExecute is not being called in my code. I have successfully used almost this exact code with a different app before. It prints 'onPreExecute' and the successful result of the JSON fetch from doInBackground just before return result; but then onPostExecute doesn't print anything - with the super call or not - and moreover doesn't return my string to the UI thread. Any ideas?
public class PrivateLoadFromServer extends AsyncTask<String, Integer, String> {
InputStream is = null;
String result = null;
String error_text="";
JSONObject j = null;
String url;
SQLiteOpenHelper helper;
CustomActivity activity;
private Context context;
private ProgressDialog dialog;
private int count;
String employee;
String text;
public PrivateLoadFromServer(CustomActivity activity,String employee,String url){
this.url=url;
this.employee=employee;
this.activity=activity;
}
#Override
protected void onPreExecute() {
system.out.println("onPreExecute");
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
System.out.println("onPostExecute");
activity.setJSONResult(result);
/*
if(result!=null){
System.out.println("Task reported successful");
taskHandler.taskSuccessful(this.result);
activity.setJSONResult(this.result);
} else {
taskHandler.taskFailed();
}
*/
//return;
}
#Override
protected String doInBackground(String... params) {
System.out.println("Running aSyncTask");
// Successful code to get JSON result string from server omitted.
System.out.println("Raw at doInBackground: " + result);
return result;
EDIT: Should've posted this originally, I call it as an inner class in CustomActivity like this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
helper=new DBHelper(this);
loadBasicData();
}
private void loadBasicData() {
// If you can encode all of these into one JSON Object, cool.
String url="*****" //Omitted URL.
String employee=null;
PrivateLoadFromServer syncTask = new PrivateLoadFromServer(this,employee,url);
syncTask.execute();
try {
syncTask.get(15000, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (TimeoutException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("JSONResult at Activity:"+jsonResult); // jsonResult is null
}
}
public void setJSONResult(String result){
System.out.println("setJSONResult"+result);
this.jsonResult=result; // jsonResult is a field in the Activity.
}
Because you are calling get, the JSON result is also returned from this method (see the source code of AsyncTask.java. So you can call your method directly on the output.
try {
setJSONResult(syncTask.get(15000, TimeUnit.MILLISECONDS));
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (TimeoutException e) {
e.printStackTrace();
}
Check if your are explicitly cancelling AsyncTask somewhere in the code before it could postExecute.
onPostExecute() is called on the main UI thread. If its not getting called, it means your UI thread is blocked doing something else.