Develop Reference

How to wait for an activity to finish in asynctask

I know that the purpose of the AsyncTask is to run asynchronously with other tasks of the app and finish in the background, but apparently I need to do this, I need to start an activity from AsyncTask and since I cant extend an activity in this class I can not use startactivityforresult, so how can I wait till my activity finishes?
Here is my code:
public class ListSpdFiles extends AsyncTask<Void, Void, String[]> {
public AsyncResponse delegate = null;
private static final String TAG = "ListSpdFiles: ";
Context applicationContext;
ContentResolver spdappliationcontext;
public final CountDownLatch setSignal= new CountDownLatch(1);
private final ReentrantLock lock = new ReentrantLock();
String username = "";
/**
* Status code returned by the SPD on operation success.
*/
private static final int SUCCESS = 4;
private boolean createbutt;
private boolean deletebutt;
private String initiator;
private String path;
private String pass;
private String url;
private SecureApp pcas;
private boolean isConnected = false; // connected to PCAS service?
private String CurrentURL = null;
private PcasConnection pcasConnection = new PcasConnection() {
#Override
public void onPcasServiceConnected() {
Log.d(TAG, "pcasServiceConnected");
latch.countDown();
}
#Override
public void onPcasServiceDisconnected() {
Log.d(TAG, "pcasServiceDisconnected");
}
};
private CountDownLatch latch = new CountDownLatch(1);
public ListSpdFiles(boolean createbutt, boolean deletebutt, String url, String pass, Context context, String initiator, String path, AsyncResponse asyncResponse) {
this.initiator = initiator;
this.path = path;
this.pass= pass;
this.url= url;
this.createbutt= createbutt;
this.deletebutt=deletebutt;
applicationContext = context.getApplicationContext();
spdappliationcontext = context.getContentResolver();
delegate = asyncResponse;
}
private void init() {
Log.d(TAG, "starting task");
pcas = new AndroidNode(applicationContext, pcasConnection);
isConnected = pcas.connect();
}
private void term() {
Log.d(TAG, "terminating task");
if (pcas != null) {
pcas.disconnect();
pcas = null;
isConnected = false;
}
}
#Override
protected void onPreExecute() {
super.onPreExecute();
init();
}
#Override
protected String[] doInBackground(Void... params) {
CurrentURL = getLastAccessedBrowserPage();
// check if connected to PCAS Service
if (!isConnected) {
Log.v(TAG, "not connected, terminating task");
return null;
}
// wait until connection with SPD is up
try {
if (!latch.await(20, TimeUnit.SECONDS)) {
Log.v(TAG, "unable to connected within allotted time, terminating task");
return null;
}
} catch (InterruptedException e) {
Log.v(TAG, "interrupted while waiting for connection in lsdir task");
return null;
}
// perform operation (this is where the actual operation is called)
try {
return lsdir();
} catch (DeadServiceException e) {
Log.i(TAG, "service boom", e);
return null;
} catch (DeadDeviceException e) {
Log.i(TAG, "device boom", e);
return null;
}
}
#Override
protected void onPostExecute(String[] listOfFiles) {
super.onPostExecute(listOfFiles);
if (listOfFiles == null) {
Log.i(TAG, "task concluded with null list of files");
} else {
Log.i(TAG, "task concluded with the following list of files: "
+ Arrays.toString(listOfFiles));
}
term();
delegate.processFinish(username);
}
#Override
protected void onCancelled(String[] listOfFiles) {
super.onCancelled(listOfFiles);
Log.i(TAG, "lsdir was canceled");
term();
}
/**
* Returns an array of strings containing the files available at the given path, or
* {#code null} on failure.
*/
private String[] lsdir() throws DeadDeviceException, DeadServiceException {
Result<List<String>> result = pcas.lsdir(initiator, path); // the lsdir call to the
boolean crtbut = createbutt;
boolean dlbut= deletebutt;
ArrayList<String> mylist = new ArrayList<String>();
final Global globalVariable = (Global) applicationContext;
if (crtbut==false && dlbut == false){
if ( globalVariable.getPasswordButt()==false ) {
final boolean isusername = globalVariable.getIsUsername();
if (isusername == true) {
Log.i(TAG, "current url: " + CurrentURL);
if (Arrays.toString(result.getValue().toArray(new String[0])).contains(CurrentURL)) {
String sharareh = Arrays.toString(result.getValue().toArray(new String[0]));
String[] items = sharareh.split(", ");
for (String item : items) {
String trimmed;
if (item.startsWith("[" + CurrentURL + ".")) {
trimmed = item.replace("[" + CurrentURL + ".", "");
if (trimmed.endsWith(".txt]")) {
trimmed = trimmed.replace(".txt]", "");
mylist.add(trimmed.replace(".txt]", ""));
} else if (trimmed.endsWith(".txt")) {
trimmed = trimmed.replace(".txt", "");
mylist.add(trimmed.replace(".txt", ""));
}
Log.i(TAG, "list of files sharareh: " + trimmed);
} else if (item.startsWith(CurrentURL + ".")) {
trimmed = item.replace(CurrentURL + ".", "");
if (trimmed.endsWith(".txt]")) {
trimmed = trimmed.replace(".txt]", "");
mylist.add(trimmed.replace(".txt]", ""));
} else if (trimmed.endsWith(".txt")) {
trimmed = trimmed.replace(".txt", "");
mylist.add(trimmed.replace(".txt", ""));
}
Log.i(TAG, "list of files sharareh: " + trimmed);
}
}
}
globalVariable.setPopupdone(false);
Intent i = new Intent(applicationContext, PopUp.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.putExtra("EXTRA_SESSION_ID", mylist);
applicationContext.startActivity(i);
username = globalVariable.getUsername();
}
else if (isusername == false)
Log.i(TAG, "Wrong Input Type For Username.");
}
if (result.getState() != SUCCESS) {
Log.v(TAG, "operation failed");
return null;
}
if (result.getValue() == null) {
Log.v(TAG, "operation succeeded but operation returned null list");
return null;
}
return result.getValue().toArray(new String[0]);
}
//}
if (result.getState() != SUCCESS) {
Log.v(TAG, "operation failed");
return null;
}
if (result.getValue() == null) {
Log.v(TAG, "operation succeeded but operation returned null list");
return null;
}
return result.getValue().toArray(new String[0]);
}
public String getLastAccessedBrowserPage() {
String Domain = null;
Cursor webLinksCursor = spdappliationcontext.query(Browser.BOOKMARKS_URI, Browser.HISTORY_PROJECTION, null, null, Browser.BookmarkColumns.DATE + " DESC");
int row_count = webLinksCursor.getCount();
int title_column_index = webLinksCursor.getColumnIndexOrThrow(Browser.BookmarkColumns.TITLE);
int url_column_index = webLinksCursor.getColumnIndexOrThrow(Browser.BookmarkColumns.URL);
if ((title_column_index > -1) && (url_column_index > -1) && (row_count > 0)) {
webLinksCursor.moveToFirst();
while (webLinksCursor.isAfterLast() == false) {
if (webLinksCursor.getInt(Browser.HISTORY_PROJECTION_BOOKMARK_INDEX) != 1) {
if (!webLinksCursor.isNull(url_column_index)) {
Log.i("History", "Last page browsed " + webLinksCursor.getString(url_column_index));
try {
Domain = getDomainName(webLinksCursor.getString(url_column_index));
Log.i("Domain", "Last page browsed " + Domain);
return Domain;
} catch (URISyntaxException e) {
e.printStackTrace();
}
break;
}
}
webLinksCursor.moveToNext();
}
}
webLinksCursor.close();
return null;
}
public String getDomainName(String url) throws URISyntaxException {
URI uri = new URI(url);
String domain = uri.getHost();
return domain.startsWith("www.") ? domain.substring(4) : domain;
}}
My Activity class:
public class PopUp extends Activity {
private static final String TAG = "PopUp";
ArrayList<String> value = null;
ArrayList<String> usernames;
#Override
protected void onCreate(Bundle savedInstanceState) {
final Global globalVariable = (Global) getApplicationContext();
globalVariable.setUsername("");
Bundle extras = getIntent().getExtras();
if (extras != null) {
value = extras.getStringArrayList("EXTRA_SESSION_ID");
}
usernames = value;
super.onCreate(savedInstanceState);
setContentView(R.layout.popupactivity);
final Button btnOpenPopup = (Button) findViewById(R.id.openpopup);
btnOpenPopup.setOnClickListener(new Button.OnClickListener() {
#Override
public void onClick(View arg0) {
LayoutInflater layoutInflater = (LayoutInflater) getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
View popupView = layoutInflater.inflate(R.layout.popup, null);
final PopupWindow popupWindow = new PopupWindow(popupView, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
Button btnSelect = (Button) popupView.findViewById(R.id.select);
Spinner popupSpinner = (Spinner) popupView.findViewById(R.id.popupspinner);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(PopUp.this, android.R.layout.simple_spinner_item, usernames);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
popupSpinner.setAdapter(adapter);
popupSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
globalVariable.setUsername(usernames.get(arg2));
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
btnSelect.setOnClickListener(new Button.OnClickListener() {
#Override
public void onClick(View v) {
globalVariable.setPopupdone(true);
popupWindow.dismiss();
finish();
}
}
);
popupWindow.showAsDropDown(btnOpenPopup, 50, -30);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.poupup_menu, menu);
return true;
}}

How to call a asyncTask several times inside a loop- one after another

Actually what i am trying to do is that call an asyncTask several times inside a loop. So, first time the asyncTask will start immediately and from second time onwards, it will check whether the AsyncTask has been finished-if finished than again call it with different values.
Below is my code for the activity:
In onCreate()
btnUpload.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
count_response = 0;
newUploadWithSeparate();
}
});
The newUploadWithSeparate() method:
private void newUploadWithSeparate()
{
responseString_concat = "";
if(filePath.length > 0)
{
for(int i=0;i<filePath.length;i++)
{
count_response = i;
if(i == 0)
{
uploadAsync.execute(filePath[0]);
mHandler = new Handler() {
#Override public void handleMessage(Message msg) {
String s=(String)msg.obj;
Log.d("logIMEI","\n Response from Asynctask: " + s);
str_response_fromAsync = s;
}
};
}
else
{
uploadAsync.getStatus();
while(uploadAsync.getStatus() == AsyncTask.Status.RUNNING) // this while loop is just to keep the loop value waitining for finishing the asyncTask
{
int rx = 0;
}
if(uploadAsync.getStatus() != AsyncTask.Status.RUNNING)
{
if(uploadAsync.getStatus() == AsyncTask.Status.FINISHED)
{
if(str_response_fromAsync != "" || !str_response_fromAsync.equals("") || !str_response_fromAsync.isEmpty())
{
uploadAsync.execute(filePath[i]);
x = i;
mHandler = new Handler() {
#Override public void handleMessage(Message msg)
{
String s=(String)msg.obj;
Log.d("logIMEI","\n Response from Asynctask_" + x + ": " + s);
str_response_fromAsync = s;
}
};
}
}
}
}
}
}
}
And the asyncTask:
private class UploadFileToServer extends AsyncTask<String, Integer, String>
{
#Override
protected void onPreExecute()
{
super.onPreExecute();
}
#Override
protected String doInBackground(String... params)
{
return uploadFile(params[0]);
}
private String uploadFile(String pr)
{
//inside here calling webservice and getting a response string as result.
MyWebsrvcClass mycls = new MyWebsrvcClass();
return responseString_concat = mycls.Call(xxx,yyy) ;
}
#Override
protected void onPostExecute(String result)
{
Log.d("logIMEI" , "\n count_response : "+ count_response + " fileprath_len : " + filePath.length);
Message msg=new Message();
msg.obj=result.toString();
mHandler.sendMessage(msg);
super.onPostExecute(result);
}
}
Now the problem is that its not working as expected. The first time when value of i is equals 0 than the AsyncTask gets called and after that its not getting called anymore.
Plus, when first time AsyncTask is called- its still not directly entering to onPostExecute(). When the loop ends totally and newUploadWithSeparate() method ends then the onPostExecute() is working.
Any solutions for this or any other way to do this job done for using AsyncTask inside loop?

You cannot call execute() on the same object more than once. So create a new instance of UploadFileToServer for each iteration of the loop.

Android AsyncTask json return value

I have called an async task from my button click.In the doInBackground I have called an API and It is returning me a Json object.I want to pass the Json object to another activity on the button click.How can I can get the return Json object value so that I can send it to other activity.
Thanks.

Create Interface
public interface Listener {
void success(BaseModel baseModel);
void fail(String message);
}
Create Base model class
public class BaseModel implements Serializable {
private static final long serialVersionUID = 1L;
}
Call below method inside your onClick mehtod.
protected void userLoginData(final String userName) {
// if you want to pass multiple data to server like string or json you can pass in this constructor
UserLoginLoader userLoginLoader = new UserLoginLoader(LoginActivity.this, userName, "1234567899", new Listener() {
#Override
public void success(BaseModel baseModel) {
// here you got response in object you can use in your activity
UserLoginModel userLoginModel = (UserLoginModel) baseModel;
// you can get data from user login model
}catch(Exception exception){
exception.printStackTrace();
Utils.showAlertDialog(LoginActivity.this, "Server is not responding! Try Later.");
}
}
#Override
public void fail(String message) {
}
});
userLoginLoader.execute();
}
:- User Login Loader class
public class UserLoginLoader extends AsyncTask<String, Void, Boolean> {
private Dialog dialog;
private Listener listner;
private String deviceId;
Activity activity;
String message;
String userName;
boolean checkLoginStatus;
public UserLoginLoader(Activity activity,String userName, String deviceId, Listener listener) {
this.listner = listener;
this.userName =userName;
this.activity = activity;
this.deviceId = deviceId;
}
#Override
protected Boolean doInBackground(String... arg0) {
//User login web service is only for making connection to your API return data into message string
message = new UserLoginWebService().getUserId(userName, deviceId);
if (message != "null" && !message.equals("false")) {
return true;
}
return false;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
dialog = new Dialog(activity, R.style.CustomDialogTheme);
dialog.setContentView(R.layout.progress);
dialog.setCancelable(false);
dialog.show();
}
#Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
BaseModel baseModel = null;
if (!message.equals("null") && (!message.equals("false")) )
baseModel = parseData(message, result);
if (dialog.isShowing()) {
dialog.dismiss();
dialog.cancel();
dialog = null;
}
if (listner != null) {
if (result && baseModel != null)
listner.success(baseModel);
else
listner.fail("Server not responding! Try agian.");
} else
listner.fail("Server not responding! Try agian.");
}
//call parser for parsing data return data from the parser
private BaseModel parseData(String responseData, Boolean success) {
if (success == true && responseData != null
&& responseData.length() != 0) {
UserLoginParser loginParser = new UserLoginParser(responseData);
loginParser.parse();
return loginParser.getResult();
}
return null;
}
}
This is you Login parser class
public class UserLoginParser {
JSONObject jsonObject;
UserLoginModel userLoginModel;
/*stored data into json object*/
public UserLoginParser(String data) {
try {
jsonObject = new JSONObject(data);
} catch (JSONException e) {
Log.d("TAG MSG", e.getMessage());
e.printStackTrace();
}
}
public void parse() {
userLoginModel = new UserLoginModel();
try {
if (jsonObject != null) {
userLoginModel.setUser_name(jsonObject.getString("user_name")== null ? "": jsonObject.getString("user_name"));
userLoginModel.setUser_id(jsonObject.getString("user_id") == null ? "" : jsonObject.getString("user_id"));
userLoginModel.setFlag_type(jsonObject.getString("flag_type") == null ? "" : jsonObject.getString("flag_type"));
} else {
return;
}
} catch (Exception exception) {
exception.printStackTrace();
}
}
/*return ship name list which is stored into model */
public UserLoginModel getResult() {
return userLoginModel;
}
}

Write a callback method in the Activity that takes in the argument that you wish to pass from AsyncTask to that Activity. Send reference to the Activity to AysncTask while creating it. From doInBackground() method make a call to this callback method with the data your API returns.
Code would be something like -
public class TestAsyncTask extends AsyncTask<Integer, Integer, String[]> {
Activity myActivity;
public TestAsyncTask(Activity activity) {
this.myActivity = activity;
}
#Override
protected String[] doInBackground(Integer... params) {
String data = yourApi();
myActivity.callback(data);
}
}
public class MyActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
new TestAsyncTask(this).execute(someId);
}
public void callback(String data) {
//process data
}
}
Just for the record you can directly get return value from doInBackground() method by calling get() on it.
String data = new TestAsyncTask(this).execute(someId).get();
But note this may block your UI thread as it will wait for the doInBackground() method to complete it's execution.

I need to run several AsyncTask in Android but only when before task has been terminated

I need to run several times the same AsyncTask in Android (passing a different file parameter to download from FTP server), but I need one after other, not in parallel, I want just do this one at time, Doing one when the other one has been terminated/finished.
So far I have this code, but it's no working properly, last task never ends:
private class FtpTask extends AsyncTask<String, Void, Integer> {
private String msg = "";
private String bean = "";
public FtpTask(String msg, String bean) {
this.msg = msg;
this.bean = bean;
}
protected void onPreExecute() {
showProgress(true, "Syncronizing", "Processing " + msg + ", wait...");
}
#Override
protected Integer doInBackground(String... params) {
if (bean.trim().equals("")) {
bean = params[0];
}
String file = Util.getMapFiles().get(bean);
int total = 0;
try {
FtpServerUtil ftp = new FtpServerUtil();
ArrayList<String> fileRows = ftp.lerArquivo(file);
total = insertRecords(bean, fileRows);
} catch (IOException e) {
Log.e(Const.TAG, "Lendo arquivo no FTP", e);
}
if (total > 0) {
Util.setSharedPrefValue("data_sinc_" + bean.toLowerCase(), Util.dateTimeToStringBR(null), context);
}
return total;
}
protected void onPostExecute(Integer total) {
showProgress(false, null, null);
String msg = "";
if (total > 0) {
msg = total + " records [" + bean + "] sincronized";
} else {
msg = "No records...";
}
Util.showToast(msg, activity);
}
}
...
#TargetApi(Build.VERSION_CODES.HONEYCOMB)
private void StartAsyncTaskInParallel(FtpTask task) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
} else {
task.execute();
}
}
..
FtpTask ftpTask1 = new FtpTask("Clientes","Cliente");
FtpTask ftpTask2 = new FtpTask("Médicos","Medico");
StartAsyncTaskInParallel(ftpTask1);
StartAsyncTaskInParallel(ftpTask2);
How could I achieve that?

You need to start next AsyncTask in Previous AsyncTask's onPostExecute:
Call ftpTask2 in onPostExecute of ftpTask1
Call ftpTask3 in onPostExecute of ftpTask2
Call ftpTask4 in onPostExecute of ftpTask3
...
To implement this, you can use Java Queue to maintain the list of AsyncTask remaining.
Sample code:
private class FtpTask extends AsyncTask<String, Void, Integer> {
// ...
private Queue<FtpTask> queue;
public FtpTask(String msg, String bean, Queue<FtpTask> queue) {
// ...
this.queue = queue;
}
protected void onPreExecute() {
}
#Override
protected Integer doInBackground(String... params) {
// ...
}
protected void onPostExecute(Integer total) {
// ...
FtpTask nextTask = this.queue.poll();
if (nextTask != null) {
nextTask.execute();
}
}
}
To use:
Queue<FtpTask> queue = new LinkedList<>();
queue.add ( asyncTask1);
queue.add ( asyncTask2);
queue.add ( asyncTask3);
queue.add ( asyncTask4);
FtpTask firstAsync = queue.poll();
firstAsync.execute();

Android - How to get calling Activity?

An Activity (SignInActivity) is calling a method in FunkcjeAPI which execute an AsyncTask.
My AsyncTask should show a ProgressDialog using an calling Activity. I don't know how to give it an correct Activity to the constructor. I tried a lot of thing, read a lot of tutorials and questions on SO, but I can't find solution. FunkcjeAPI isn't an Activity so I can't write new Logowanie(this).execute(argumenty);
AsyncTask calling code :
public class FunkcjeAPI {
static String dozwrotu = null;
public static String zalogujSie(final String nick, final String haslo)
{
String[] argumenty = {nick, haslo};
new Logowanie(/* WHAT HERE ? */).execute(argumenty); // HELP ME IN THAT LINE !!!!!!!!!!!!!
return dozwrotu;
}
My AsyncTask class code (it is in FunkcjeAPI class):
private class Logowanie extends AsyncTask<String, Void, String>
{
Activity wywolujaceActivity;
public Logowanie(Activity wywolujaceActivity) {
this.wywolujaceActivity = wywolujaceActivity;
}
#SuppressWarnings("deprecation")
#Override
protected void onPreExecute() {
wywolujaceActivity.showDialog(SignInActivit.PLEASE_WAIT_DIALOG);
}
#Override
protected String doInBackground(final String... argi) {
final JSONParser jParser = new JSONParser();
new Thread(new Runnable() {
public void run() {
final String json = jParser.getJSONFromUrl("http://tymonradzik.pl/THUNDER_HUNTER/thapi.php?q=login&username=" + argi[0] + "&password=" + argi[1] + "&imei=");
Handler mainHandler = new Handler(Looper.getMainLooper());
mainHandler.post(new Runnable() {
#Override
public void run() {
JSONObject jObject;
try {
jObject = new JSONObject(json);
Log.wtf("Link", "http://tymonradzik.pl/THUNDER_HUNTER/thapi.php?q=login&username=" + argi[0] + "&password=" + argi[1] + "&imei=");
Log.wtf("Link", json);
String error = jObject.getString("error");
if(error == "You reached daily query limit !") { nadajWartosc("You reached daily query limit !"); }
if(error == "0") {nadajWartosc(jObject.getString("token"));}
if(error == "1") {nadajWartosc("1");}
if(error == "Invalid username") {nadajWartosc("Invalid username");}
if(error == "Invalid password") {nadajWartosc("Invalid password");}
if(error == "This user is already logged in !") {nadajWartosc("This user is already logged in !");}
} catch (JSONException e1) {
e1.printStackTrace();
}
catch (NullPointerException e)
{
e.printStackTrace();
}
}
});
}}).start();
return dozwrotu;
}
#Override
protected void onPostExecute(String result) {
wywolujaceActivity.removeDialog(SignInActivit.PLEASE_WAIT_DIALOG);
}
}

Add one more parameter to zalogujSie() method that takes an Activity, and then use this parameter to start the AsyncTask:
public static String zalogujSie(Activity activity, final String nick, final String haslo)
{
// .....
new Logowanie(activity).execute(argumenty);
return dozwrotu;
}
Then you would call this method from the activity like this:
FunkcjeAPI.zalogujSie(this, "Nick", "Haslo");