I have written a code to download some data from internet. Than i wanted to put it into asyncTask. And after that downloading stopped working. It looks like it cant finish try{} part so skips to exeption.
From main activity "Nekaj" i call loadData() class, which extends AsyncData. From there i call "oto" class inside try command. "oto" class is used to read stuff from internet and returns array of strings. This worked when i called oto class directly from "Nekaj"class. What did I do wrong with using AsyncTask?
Here is the code:
public class Nekaj extends Activity {
TextView Tkolo, Tbroj1;
String[] brojevi_varijabla;
String privremena_varijabla = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.bez_provjere_739);
Tkolo = (TextView) findViewById(R.id.Xkolo);
Tbroj1 = (TextView) findViewById(R.id.Xbroj1);
/*
* try { privremena_varijabla = test.kolo_739();
* Tkolo.setText(privremena_varijabla); } catch (Exception e) { // TODO
* Auto-generated catch block e.printStackTrace(); }
*/
new loadData().execute();
}
public class loadData extends AsyncTask<String, Integer, String> {
#Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
Oto test = new Oto();
try {
brojevi_varijabla = test.brojevi_739();
if (Integer.valueOf(brojevi_varijabla[0]) > 10) {
Tbroj1.setText("" + brojevi_varijabla[0]);
} else {
Tbroj1.setText(" " + brojevi_varijabla[0]);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
public class Oto {
public String[] brojevi_739() throws Exception {
int i = 0;
int uvjet = 0;
int varijabla = 0;
char[] znak = { '>', '<' };
BufferedReader in = null;
String data[] = null;
String provjera = "date-info";
int[] polje = new int[2];
try {
HttpClient klijent = new DefaultHttpClient();
URI webstranica = new URI(
"https://www.aaa.bb");
HttpGet zahtjev = new HttpGet();
zahtjev.setURI(webstranica);
HttpResponse odgovor = klijent.execute(zahtjev);
in = new BufferedReader(new InputStreamReader(odgovor
.getEntity().getContent()));
StringBuffer brojevi = new StringBuffer("");
String brojevi_string = null;
String neki_string = null;
String red = "";
in.skip(21000);
while ((red = in.readLine()) != null) {
varijabla = red.indexOf(provjera);
if (varijabla != -1) {
// 1. KOLO
if (uvjet == 0) { // onda sadrži taj
// substring
// !!!!
red = in.readLine(); // sada string red sadrži ono
// što
// želim, još moram samo to
// izrezati!!
do {
if (i == 0) {
varijabla = red.indexOf(znak[i]);
}
else {
varijabla = red.indexOf(znak[i], polje[0]);
}
if (varijabla != -1) // ako taj znak postoji u
// stringu
{
if (i == 0) {
polje[i] = varijabla + 1;
}
else {
polje[i] = varijabla;
}
i++;
}
} while (i <= 1);
neki_string = red.substring(polje[0], polje[1]);
Tkolo.setText(neki_string);
provjera = "Dobitna kombinacija";
uvjet++;
continue;
}
}
}
in.close();
brojevi_string = brojevi.toString();
data = brojevi_string.split("\n");
return data;
} finally {
if (in != null) {
try {
in.close();
return data;
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}}
What you are doing wrong is Tbroj1.setText() inside the doInBackground() method. What you have to do is to use the onPostExecute method to post your data on the UI:
public class loadData extends AsyncTask<String, Integer, Boolean> {
protected Long doInBackground(String... arg0) {
Oto test = new Oto();
Boolean result = false;
try {
brojevi_varijabla = test.brojevi_739();
result = true;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return result;
}
protected void onPostExecute(Boolean result) {
if(result){
if (Integer.valueOf(brojevi_varijabla[0]) > 10) {
Tbroj1.setText("" + brojevi_varijabla[0]);
} else {
Tbroj1.setText(" " + brojevi_varijabla[0]);
}
}
}
}
Actually, You are trying to update UI in doInBackGround() of your AsyncTask, so its not allowed (doInBack.. runs in non UI Thread..), So put the UI updation code in onPostExecute() of AsyncTask..
Try this and let me know what happen..
public class loadData extends AsyncTask<String, Integer, String> {
#Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
Oto test = new Oto();
try {
brojevi_varijabla = test.brojevi_739();
if(brojevi_varijabla != null)
return brojevi_varijabla[0];
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result)
{
if(result != null)
{
if (Integer.valueOf(result) > 10) {
Tbroj1.setText("" + result;
} else {
Tbroj1.setText(" " + result);
}
}
}
}
use onPostExecute(Void result1) {}
to catch the result and perform the action required over there
You can't manipulate UI elements directly on a non-UI (background) thread, which is where doInBackground() always runs. The usual way of using AsyncTask is to get the data in doInBackground(), return it as a value, and then process the UI changes in onPostExecute(). For example:
public class loadData extends AsyncTask<String, Integer, String> {
#Override
protected String doInBackground(String... arg0) {
Oto test = new Oto();
try {
brojevi_varijabla = test.brojevi_739();
if (Integer.valueOf(brojevi_varijabla[0]) > 10) {
return "" + brojevi_varijabla[0];
} else {
return " " + brojevi_varijabla[0];
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (result != null) Tbroj1.setText(result);
}
}
Related
In my App I am hitting a service which can have no result to n number of results(basically some barcodes). As of now I am using default circular progressbar when json is parsed and result is being saved in local DB(using sqlite). But if the json has large number of data it sometimes takes 30-45 min to parse and simultaneously saving that data in DB, which makes the interface unresponsive for that period of time and that makes user think the app has broken/hanged. For this problem I want to show a progressbar with the percentage stating how much data is parsed and saved so that user get to know the App is still working and not dead. I took help from this link but couldn't find how to achieve. Here's my Asynctask,
class BackGroundTasks extends AsyncTask<String, String, Void> {
private String operation, itemRef;
private ArrayList<Model_BarcodeDetail> changedBarcodeList, barcodeList;
private ArrayList<String> changeRefList;
String page;
public BackGroundTasks(String operation, String itemRef, String page) {
this.operation = operation;
this.itemRef = itemRef;
this.page = page;
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
if (dialog == null) {
dialog = ProgressDialog.show(mActivity, null,
"Please wait ...", true);
}
}
#Override
protected Void doInBackground(String... params) {
// TODO Auto-generated method stub
try{
if (!connection.HaveNetworkConnection()) {
dialog.dismiss();
connection.showToast(screenSize, "No Internet Connection.");
return null;
}
if (operation.equalsIgnoreCase("DownloadChangeItemRef")) {
changeRefList = DownloadChangeItemRef(params[1]);
if (changeRefList != null && !changeRefList.isEmpty()) {
RefList1.addAll(changeRefList);
}
}
if ((changeRefList != null && changeRefList.size() >0)) {
setUpdatedBarcodes(changedBarcodeList);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#SuppressLint("SimpleDateFormat")
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
}
}
ArrayList<String> DownloadChangeItemRef(String api_token) {
ArrayList<String> changedRefList = null;
HttpClient httpClient = new DefaultHttpClient();
HttpPost postRequest = new HttpPost(thoth_url + "/" + todaysDate
+ "?&return=json");
String url = thoth_url + "/" + todaysDate + "?&return=json";
String result = "";
try {
changedRefList = new ArrayList<String>();
ResponseHandler<String> responseHandler = new BasicResponseHandler();
result = httpClient.execute(postRequest, responseHandler);
JSONObject jsonObj = new JSONObject(result);
JSONArray jsonarray = jsonObj.getJSONArray("changes");
if (jsonarray.length() == 0) {
return null;
}
for (int i = 0; i < jsonarray.length(); i++) {
JSONObject obj = jsonarray.getJSONObject(i);
changedRefList.add(obj.getString("ref"));
}
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
// when there is no thoth url
Log.i("inclient: ", e.getMessage());
return null;
} catch (Exception e) {
// when there are no itemref
return null;
}
return changedRefList;
}
private boolean setUpdatedBarcodes(
final ArrayList<Model_BarcodeDetail> changedBarcodeList2) {
try {
BarcodeDatabase barcodeDatabase = new BarcodeDatabase(mActivity);
barcodeDatabase.open();
for (Model_BarcodeDetail model : changedBarcodeList2) {
barcodeDatabase.updateEntry(model, userId);
}
n++;
barcodeDatabase.close();
if (RefList1.equals(RefList)) {
if (dialog != null) {
dialog.dismiss();
}
connection.showToast(screenSize, "Barcodes updated successfully");
}
} catch (Exception e) {
Log.i("Exception caught in: ", "setDownloadedBarcodes method");
e.printStackTrace();
return false;
}
return true;
}
I am developing Android application(online marketing), within this project i am using socket programming for communication with server, when i communicate with server if server does not give me any response within 30 sec then my asynctask will close automatically, but now problem is i want to save server response in sqlite on receiving response from server please provide me the necessary help thank
you in advance.
Here is My Asyntask :
public class SendToserver extends AsyncTask<Integer, Integer, Integer>
{
int iReturn;
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
progressDialog(Registartion.this, "Please Wait...");
super.onPreExecute();
}
#Override
protected Integer doInBackground(Integer... params) {
// TODO Auto-generated method stub
ServerData = runm(IMEINo);
if (ServerData.equalsIgnoreCase("IsNull"))
{
iReturn = 2;
}
else {
iReturn = 1;
}
return iReturn;
}
#Override
protected void onPostExecute(Integer result) {
// TODO Auto-generated method stub
if (iReturn == 1)
{
String ServerIP = edtServerIpAddress.getText().toString();
String ServerPort = edtServerPort.getText().toString();
registartionModel = new RegistartionModel();
registartionModel.setServerIPAdreess(ServerIP);
registartionModel.setPort(ServerPort);
registrationDb = new RegistrationDb(getApplicationContext());
registrationDb.open();
registrationDb.insertData(registartionModel);
registrationDb.close();
Intent i = new Intent(getBaseContext(), LoginActivity.class);
startActivity(i);
Registartion.this.finish();
System.gc();
}
else if (iReturn == 2)
{
showDialogBox("Please Input Correct Server IP and Port");
}
super.onPostExecute(result);
}
}
My Server Communication Method(runm):
#SuppressLint("NewApi")
public String runm(String DId)
{
try {
socket = new Socket(SERVER_IP, SERVERPORT);
out = new PrintStream(socket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
out.write((DId + "|" +"REG").getBytes());
ServerData = in.readLine();
System.err.println("Server Data in Runm :- " + ServerData);
if(ServerData == null || ServerData.equalsIgnoreCase(""))
{
ServerData="IsNull";
}
}
catch (NetworkOnMainThreadException e)
{
ServerData = "IsNull";
}catch (IOException ex) {
ServerData = "IsNull";
}
return ServerData;
}
Should i use Broadcast Receiver ?
I'm trying to implement an asynchronous access to internet using AsyncTask, but in log cat PID and TID of my logging are the same, because AsyncTask doesn't create a parallel queue, so my app crashes with a NetworkOnMainThreadException.
Here's my subclass code :
class BL_SimpleAsyncTask extends AsyncTask<Void, Void, Void> {
String requestServer;
HashMap<String, String> postRequestBody;
//------------------------// answer from http client
static DefaultHttpClient sharedClient = null;
boolean isPostRequest;
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected Void doInBackground(Void... params) {
System.out.println("bg started");
if (sharedClient == null) {
sharedClient = new DefaultHttpClient();
}
HttpPost post = new HttpPost(requestServer);
String postBody = new String();
postBody += "{";
for (String key : postRequestBody.keySet()) {
String result = String.format("\"%s\":\"%s\",", key, postRequestBody.get(key));
postBody += result;
}
System.out.println("body initialized");
postBody.substring(0, postBody.length() - 1);
postBody += "}";
try {
post.setEntity(new StringEntity(postBody));
} catch (UnsupportedEncodingException e) {
System.out.println(e.getMessage());
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("entity set");
try {
if (post != null) {
System.out.println("starting request....");
HttpResponse response = sharedClient.execute(post);
System.out.println("responce recieved");
} else {
System.out.println("null request");
}
// System.out.println(response) ;
} catch (ClientProtocolException e) {
System.out.println(e.getMessage());
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
System.out.println(e.getMessage());
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
}
}
}
So, to start post-request, I simply do the following :
BL_SimpleAsyncTask obj = new BL_SimpleAsyncTask() ;
obj.requestServer = "https://api.orbios.com/v1/auth/sign-in" ;
obj.postRequestBody = new HashMap<String, String> () ;
obj.postRequestBody.put ("password", password) ;
obj.postRequestBody.put("email", email ) ;
obj.isPostRequest = true ;
System.out.println("start bg thread") ;
obj.doInBackground() ;
What am I doing wrong?
You are not supposed to call doInBackground() yourself. Just call execute() and let the framework call your doInBackground() in a background thread.
Instead of calling directly doInBackground() you should be calling execute method.
I am currently working with the tab host and fragment. Currently I set fragment a to download json A and fragment B to download json B , the problem is when I switch fragment, the fragment A onPostExecute function will fall into the fragment B one , is there any way to fix this?
Thanks
Tab host:
tabHost = (FragmentTabHost) findViewById(R.id.tabhost);
tabHost.setup(this, getSupportFragmentManager(), R.id.tabcontent);
tabHost.addTab(
tabHost.newTabSpec("Home").setIndicator("",
res.getDrawable(R.drawable.btn_about)), Home.class,
null);
tabHost.addTab(
tabHost.newTabSpec("About").setIndicator("",
res.getDrawable(R.drawable.btn_about)), About.class,
null);
The async task
public class JSONReader {
public static final String TAG = "JSONReader";
public ArrayList<Record> records;
public Record myRecordObj;
public ArrayList<GalleryImage> images;
public String url;
public int failCount = 0; // retry twice
public Context ctx;
public String readCase;
public JSONReader(String _url, Context _ctx , String _readCase) {
url = _url;
ctx = _ctx;
readCase = _readCase;
}
public void getJSON() {
new JSONDownload().execute(url);
}
private class JSONDownload extends AsyncTask<String, Void, JSONObject> {
// TODO Auto-generated method stub
StringBuilder builder = new StringBuilder();
String temp = "";
String json = ""; // json content
InputStream input = null;
OutputStream output = null;
HttpURLConnection connection = null;
#Override
protected JSONObject doInBackground(String... params) {
// TODO Auto-generated method stub
try {
Log.d(TAG, "Start reading: " + url);
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK)
return null;
// return "Server returned HTTP " + connection.getResponseCode()
// + " " + connection.getResponseMessage();
input = connection.getInputStream();
BufferedReader reader = new BufferedReader(
new InputStreamReader(input));
while ((temp = reader.readLine()) != null) {
builder.append(temp);
}
json = builder.toString();
} catch (Exception e) {
return null;
} finally {
try {
if (input != null)
input.close();
if (output != null)
output.close();
} catch (IOException ignored) {
}
if (connection != null)
connection.disconnect();
}
try {
return new JSONObject(json);
} catch (JSONException e) {
e.printStackTrace();
return null;
}
}
#Override
protected void onPostExecute(JSONObject result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
onJSONDownloaded(result);
}
}
public void onJSONDownloaded(JSONObject result) {
// TODO Auto-generated method stub
if (result != null) {
failCount = 0;
if (readCase.equals("leaderBoard")){
records = new ArrayList<Record>();
try {
JSONObject myRecord = result.getJSONObject("myRecord");
if (myRecord != null) {
myRecordObj = new Record(myRecord.getString("pic"),myRecord.getString("name"),myRecord.getString("score"));
}
JSONArray topRecords = result.getJSONArray("topRecord");
for (int i = 0; i < topRecords.length(); i++) {
JSONObject topRecord = topRecords.getJSONObject(i);
String topName = topRecord.getString("name");
String topPic = topRecord.getString("pic");
String topScore = topRecord.getString("score");
records.add(new Record(topPic, topName, topScore));
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
((LeaderBoardDetail)ctx).setData(records,myRecordObj);
} else if (readCase.equals("galleryList")){
images = new ArrayList<GalleryImage>();
try {
JSONArray imageList = result.getJSONArray("images");
for (int i = 0; i < imageList.length(); i++) {
JSONObject image = imageList.getJSONObject(i);
images.add(new GalleryImage(image.getString("url"),image.getString("thumbUrl"),image.getString("category"),image.getString("userPic"),image.getString("name")));
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//exception
if (((FragmentActivity) ctx).getSupportFragmentManager().findFragmentById(R.id.tabcontent).getTag().equals("Gallery")) {
PhotoGallery galleryFragment = (PhotoGallery) ((FragmentActivity) ctx).getSupportFragmentManager().findFragmentById(R.id.tabcontent);
galleryFragment.setData(images);
}
}
} else {
if (failCount <= 1) { // check global_conf twice if fail
failCount++;
Log.d(TAG, "No of retry" + failCount);
new JSONDownload().execute(url); // Retry download json
} else {
failCount = 0;
}
}
}
}
I used it in my app this way which works for me and answer is a bit similar to another answer but few additions and more detail. Hope it help you too.
NOTE: This is just a idea, u need to try, it may vary as per your app architect.
At your activity make the task object global [make sure set task obj null once task is finish]
JSDownload js = null;
public void getJSON() {
if(js != null && js.getStatus() == AsyncTask.Status.RUNNING)
{
js.cancel(true);
if(js.isCancelled())
{
js = new JSONDownload();
js.execute(url);
}
else
{
js = new JSONDownload();
js.execute(url);
}
}
At the Async class side....[make sure u take care null result # onpostExcute]
class JSONDownload extends AsyncTask<String, Void, JSONObject>
{
protected JSONObject doInBackground(String... params) {
// TODO Auto-generated method stub
try {
if(!this.isCancelled())
{
//make http connection ..
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
//as we are in steps in bg check iscancel .. again
//if its a loop here we call break; and return null once only..
if(this.isCancelled())
return null;
// connection status check and get buffer etc .. code here
if(this.isCancelled())
return null;
//read data
return data;
}
} catch (Exception e) {
return null;
}
}
#Override
protected void onCancelled(){
// If you write your own implementation, do not call super.onCancelled(result).
}
}
Use the global async task variable
LongOperation LongOperationOdeme = new LongOperation();
and set:
LongOperationOdeme.cancel(true);
This will stop any async task running at that moment, it's what the back button does
If you are not looking for a simplest answer but for a maybe more interesting and elegant, have a peek at this article, especially if you find functional programming interesting.
It's easier than it looks, i was almost unfamiliar to FP before this article but it covers common problems related to AsyncTask and asynchronicity in Android in general, so I got the gist and consider to use Observables instead of AsyncTask in the future projects myself. It is RxJava and it can solve your problem gracefully: "The fromFragment call transforms the given source observable in such a way that events will only be emitted to the fragment if it’s still alive and attached to its host activity."
One more citation form the article: "What if the user decides to back out of the Activity that triggered the task, and we are holding on to a stale reference. This not only creates a substantial memory leak, but is also worthless because meanwhile it has been detached from the application window. A problem that everyone is well aware of."
I'm trying to implement AsyncTask outside the activity class. Now the issue is status of this asynctask class is always showing as running, how do i make it finished?
This is my activity class
protected void onCreate(Bundle savedInstanceState) {
employeeAsyncTask.execute(new String[] {url});
System.out.println("Status "+employeeAsyncTask.getStatus());
//employeeAsyncTask.cancel(true);
while(employeeAsyncTask.getStatus() == AsyncTask.Status.RUNNING){
}
while (employeeAsyncTask.getStatus()== AsyncTask.Status.FINISHED) {
System.out.println("hereeeeeeeeeeeeee");
ArrayList<Employee> list = employeeAsyncTask.getEmpList();
System.out.println("Size of list "+list);
}
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_capture);
}
This is my asynctask class
public class FetchEmployeeAsyncTask extends AsyncTask<String, Void, ArrayList>{
private ArrayList<Employee> empList = null;
private boolean done = false;
/**
* #return the done
*/
public boolean isDone() {
return done;
}
/**
* #param done the done to set
*/
public void setDone(boolean done) {
this.done = done;
}
#Override
protected ArrayList doInBackground(String... url) {
// TODO Auto-generated method stub
ArrayList<Employee> employees = null;
for(String employeeUrl : url){
employees = fetch(employeeUrl);
}
return employees;
}
private ArrayList<Employee> fetch(String url) {
// TODO Auto-generated method stub
ArrayList<Employee> employees = null;
String response = null;
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
response = EntityUtils.toString(httpEntity);
employees = EmployeeXMLParser.XMLfromString(response);
System.out.println("Size in fetch "+employees.size());
//System.out.println("Employee Name :: " + employees.get(0).getFirstName() + " " + employees.get(0).getLastName());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} /*catch (XmlPullParserException e) {
// TODO Auto-generated catch block
System.out.println("Error parsing the response :: " + response);
e.printStackTrace();
}*/
return employees;
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
done = false;
}
#Override
public void onPostExecute(ArrayList employeeList){
setEmpList(employeeList);
System.out.println("in post execxute "+employeeList.size());
done = true;
}
public ArrayList<Employee> getEmpList() {
return empList;
}
public void setEmpList(ArrayList<Employee> empList) {
this.empList = empList;
}
}
I'm unable to figure out what should be included in onPostExecute().
Add a constructor that takes the activity as parameter and stores it in a field:
private MyActivity activity;
public FetchEmployeeAsyncTask(MyActivity activity) {
this.activity = activity;
}
Then in the onPostExecute method you can pass back the employee list:
#Override
public void onPostExecute(ArrayList employeeList) {
activty.onEmpListLoaded(employeeList);
}
And in your activity implement onEmpListLoaded to do whatever needs to be done.