Develop Reference

Static AsyncTask ProgressBar

Sorry if this seems a basic question. I've updated Android Studio and notice some memory leak warnings on my AsyncTasks saying I should make them static. I have made them static but can't seem to make anything like List, ProgressBar, ImageView work without getting the same memory leak warning. It seems I can't win no matter which way I try it. I guess my questions are:
Are AsyncTasks supposed to be static? The official documentation doesn't make it static but my IDE fires warnings saying they should.
If they are meant to be static, how can I start and stop a ProgressBar within the static AsyncTask.
EDIT
This still throws "This AsyncTask class should be static or leaks might occur"
private class DownloadCategoryTask extends AsyncTask<String, Integer, String> {
#Override
protected String doInBackground(String... params) {
Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
String url = Config.API_URL +
"/Index.aspx?" +
"type=3&" +
"site_id=" + SITE_ID;
String method = "GET";
String array_name = "categories";
Downloaded_category_array = Config.getJSONNew(url, method, array_name, context);
return "";
}
protected void onPostExecute(String result) {
if(isCancelled()){
return;
}
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
//Update your UI here
//showProgressBar();
}
});
Populate_category_list();
}
}

Try this solution which I found:
public class MainActivity extends AppCompatActivity {
private ProgressBar progressBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressBar = findViewById(R.id.progress_bar);
}
public void startAsyncTask(View v) {
ExampleAsyncTask task = new ExampleAsyncTask(this);
task.execute(10);
}
private static class ExampleAsyncTask extends AsyncTask<Integer, Integer, String> {
private WeakReference<MainActivity> activityWeakReference;
ExampleAsyncTask(MainActivity activity) {
activityWeakReference = new WeakReference<MainActivity>(activity);
}
#Override
protected void onPreExecute() {
super.onPreExecute();
MainActivity activity = activityWeakReference.get();
if (activity == null || activity.isFinishing()) {
return;
}
activity.progressBar.setVisibility(View.VISIBLE);
}
#Override
protected String doInBackground(Integer... integers) {
for (int i = 0; i < integers[0]; i++) {
publishProgress((i * 100) / integers[0]);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return "Finished!";
}
}
}
Reference: here

No, No need to make AsyncTasks as static.
If non static methods are trying to modify static members then IDE throws warning to make it static.
If you want to update your UI from AsyncTask use 'runOnUiThread'.
runOnUiThread(new Runnable() {
#Override
public void run() {
//Update your UI here
showProgressBar();
}
});

Looks like you are using anonymous inner class.
Here is the solution,
private class LoadData extends AsyncTask<Void, Void, String> {
LoadData() {
}
#Override
protected String doInBackground(Void... params) {
return "task finished";
}
#Override
protected void onPostExecute(String result) {
runOnUiThread(new Runnable() {
#Override
public void run() {
//Update your UI here
//showProgressBar();
}
});
}
}
//Execute your task
new LoadData().execute();

ProgressDialog not displaying

I have a progress dialog, I want it to show and dismiss when my method has finished executing. now, I have this:
progressDialog = new ProgressDialog(this);
progressDialog.setMessage("Downloading...");
progressDialog.show();
new Thread(new Runnable() {
#Override
public void run() {
try{
DownloadMethod(s);
progressDialog.dismiss();
}catch (Exception e){
Toast.makeText(prefs.this, "We can't reach the data...Try again", Toast.LENGTH_SHORT).show();
}
}
}).start();
My method DownloadMethod is executed but never shows the dialog.

Actually, It must be throwing an exception with progressDialog.dismiss(); call because you cannot update UI from a worker thread, instead use AsyncTask
e.g pass parameter to constructor
private class DownloadFilesTask extends AsyncTask<Void, Void, Void> {
TypeOf_S s;
public DownloadFilesTask(TypeOf_S s){
this.s = s;
}
#Override
protected Void doInBackground(Void... obj) {
DownloadMethod(s);
return null;
}
#Override
protected void onPostExecute(Void result) {
progressDialog.dismiss();
}
}
and call it like new DownloadFilesTask(s).execute();
or with generic parameter
private class DownloadFilesTask extends AsyncTask<TypeOf_S, Void, Void> {
#Override
protected Void doInBackground(TypeOf_S... obj) {
DownloadMethod(obj[0]);
return null;
}
#Override
protected void onPostExecute(Void result) {
progressDialog.dismiss();
}
}
and call it like new DownloadFilesTask().execute(s);

progressDialog.dismiss();is throwing an exception so move your code inside runOnUiThread() method like this:
runOnUiThread(new Runnable() {
#Override
public void run() {
progressDialog.dismiss();
}
});

as suggested by Pavneet you can use async task as follows where AsyncTask<String, void, String> corresponds to the input type progress value and last is result value you are interested so give data types accordingly.
private class DownloadFilesTask extends AsyncTask<String, void, String> {
protected String doInBackground(String... urls) {
//here do the actual downloading instead of calling the DownloadMethod(s)
}
protected void onPreExecute() {
//here show the dialog
progressDialog.show();
}
protected void onPostExecute(String result) {
//here hide the dialog
progressDialog.dismiss();
}
}
and where you are calling the download function you just call this
progressDialog = new ProgressDialog(this);
progressDialog.setMessage("Downloading...");
new DownloadFilesTask().execute(s);
//here s is assumed to be string type you can give anything

submitScoreGPGS does not work with AsyncTask

I am trying to get the Google Play Services working as following using AsyncTaks:
1 - The Login Dialog is only displayed when the user click on the leaderboard button which call the method loginGPRS() below;
2 - An ansync task is then executed which call the startLoginGRPS() method on the onPreExecute
3 - [Here is the problem] Once he is logged in, I want to call the methods submitScoreGPRS() and getLeaderBoardGPRS() in onPostExecute method, but the leaderboard dialog is never opened...
Here is the relevant source code:
#Override
public void loginGPGS() {
try {
MyAsyncTask asyncTask_a = new MyAsyncTask();
asyncTask_a.execute();
} catch (final Exception ex) {
}
}
class MyAsyncTask extends AsyncTask<Void, Void, Boolean> {
String errorMsg;
#Override
protected void onPreExecute() {
startLoginGPGS();
super.onPreExecute();
}
#Override
protected Boolean doInBackground(Void... v) {
return true;
}
#Override
protected void onPostExecute(Boolean success) {
if(success){
submitScoreGPGS(bestScore);
getLeaderboardGPGS();
}
}
}
public void startLoginGPGS() {
try {
// runOnUiThread(new Runnable() {
// public void run() {
gameHelper.beginUserInitiatedSignIn();
// }
// });
} catch (final Exception ex) {
}
}
#Override
public void submitScoreGPGS(int score) {
if(getSignedInGPGS()){
Games.Leaderboards.submitScore(gameHelper.getApiClient(),
getString(R.string.leaderboard1_id), score);
}
}

Have you trace your code??
Write something like...
Log.d("Trace","Point X"):
In the doInBackground method just before the return true, another one in the onPostExecute method just before the if and inside the if.
Take a look at your Logcat and come back...
Hope it helps.

You're executing your method on the UI thread, because onPostExecute() runs on the UI thread and your method has network execution..
You should move your method to the doInBackground() method

ProgressDialog not shown in AsyncTask

I have a huge database (40MB) on an SDCard. I need fetch data, with LIKE in query, which is very slow.
DB request takes about 5 seconds. Therefore, I need to do it asynchronously and with ProgressDialog.
I tried it with AsyncTask, but problem is with ProgressDialog. It was implemented this way:
private class GetDataFromLangDB extends AsyncTask<String, String, String> {
private final ProgressDialog dialog = new ProgressDialog(TranslAndActivity.this);
#Override
protected void onPreExecute() {
super.onPreExecute();
urDBCursor.close();
curDBCursor = null;
scaAdapter = null;
this.dialog.setMessage("Loading data...");
this.dialog.show();
}
#Override
protected String doInBackground(String... whatSearch) {
String result = "";
if (myDatabaseAdapter != null) {
curDBCursor = myDatabaseAdapter.fetchAll(whatSearch[0]);
}
return result;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
prepareListView();
}
}
The problem is that ProgressDialog is not shown during the DB request.
After finished database query, it flash on screen for a short time. When user tries
to tap on screen during database request, UI is freezed, and after DB request
message about 'not responding' is shown.
I tried it with a thread this way:
public void startProgress(View view, final String aWhatSearch) {
final ProgressDialog dialog = new ProgressDialog(MyActivity.this);
if (curDBCursor != null){
curDBCursor.close();
curDBCursor = null;
}
dialog.setMessage("Loading data...");
dialog.show();
Runnable runnable = new Runnable() {
public void run() {
curDBCursor = myDatabaseAdapter.fetchAll(aWhatSearch);
// dirty trick
try {
Thread.sleep(250); // it must be here to show progress
} catch (InterruptedException e) {
e.printStackTrace();
}
handler.post(new Runnable() {
public void run() {
if (dialog.isShowing()) {
dialog.dismiss();
}
prepareListView();
}
});
}
};
new Thread(runnable).start();
}
The result was the same, but when I used the trick with Thread.sleep(250);
ProgressDialog was shown during the database request. But it is not spinning,
it looks freezed during the DB request.
DB stuff is called this way (after tap on search button):
btnSearchAll.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// AsyncTask
new GetDataFromLangDB().execute(edtTextToSearch.getText().toString());
// or Thread
//startProgress(null, edtTextToSearch.getText().toString());
}
});
I found a lot of problems like this in SO, but nothing was useful for me.
Could it be that DB is on SD Card?

I put the definition of the dialog into the AsyncTask Class and it works fine for me.
Take a look at this exampel (You have to change NAMEOFCLASS in the name of your CLASS:
private class doInBackground extends AsyncTask<Integer, Integer, Void> {
final ProgressDialog dialog = new ProgressDialog(NAMEOFCLASS.this) {
#Override
protected void onPreExecute() {
dialog.setCancelable(false);
dialog.setTitle(getString(R.string.daten_wait_titel));
dialog.setIcon(R.drawable.icon);
dialog.setMessage(getString(R.string.dse_dialog_speichern));
dialog.show();
}
#Override
protected void onCancelled() {
dialog.cancel();
}
....
#Override
protected void onProgressUpdate(Integer... values) {
// DO YOUR UPDATE HERE
}
#Override
protected void onPostExecute(Void result) {
dialog.dismiss();
}
}

Maybe this SO answer could help you. It looks like similar problem. Try to use AsyncQueryHandler for querying your database

declare you Dialog box on Class (Activity) level like this
private ProgressDialog dialog = null;
show the progress dialog and call the AsyncTask class when you want to start you Busy work..like onButton click or any
dialog = ProgressDialog.show(this,"Sending Email to your account please! wait...", true);
SendingEmailTask task = new SendingEmailTask();
String s = "";
task.execute(s);
create your inner class like
private class SendingEmailTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... urls) {
//do your work here..
// like fetching the Data from DB or any
return null;
}
#Override
protected void onPostExecute(String str) {
//hide progress dialog here
dialog.dismiss();
}
}
let me know if this help!!

AsyncTask as Inner class and static field issue

I have a method searchPlace() that updates a static Arrays of custom Place Object in a class A (FindItOnMap) with a google map, and a method updateMap() that updates the various geopoints .
I invoke these methods Button.onClick and all works properly.
Since these methods use internet data this operation could take a while, I have been looking for the implementation of an inner class B(YourCustomAsyncTask) inside the class A that extends AsyncTask to show a waiting dialog during the processing of these two methods
An user suggested a solution in this form (that apparently seems valid):
public class FindItOnMap extends MapActivity {
static Place[] foundResults;
private ProgressDialog dialog;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.ricerca_condominio);
mapView = (MapView)findViewById(R.id.mapView);
...........
((ImageButton) findViewById(R.id.btSearch)).setOnClickListener(mSearchListenerListener);
}
OnClickListener mSearchListener = new OnClickListener() {
public void onClick(View v) {
String location=editorLocation.getText().toString();
String name=editorName.getText().toString();
//Call the AsyncTask here
new YourCustomAsyncTask().execute(new String[] {name, location});
}
};
private class YourCustomAsyncTask extends AsyncTask <String, Void, Void> {
#Override
protected void onPreExecute() {
dialog = new ProgressDialog(Main.this);
dialog.setMessage("Loading....");
dialog.setIndeterminate(true);
dialog.setCancelable(true);
dialog.show(); //Maybe you should call it in ruinOnUIThread in doInBackGround as suggested from a previous answer
}
#Override
protected Void doInBackground(String... strings) {
try {
search(strings[0], string[1]);
return null;
} catch(Exception e) {
}
}
#Override
protected void onPostExecute(Void params) {
updateMapWithResult();
dialog.dismiss();
//result
}
.....
}
The waiting dialog is showed and the methods are invoked in background,
However for some strange reason the static list foundResults results filled with various null items...
How is this possible?
If I invoke the method search(location, name) outside the inner class all works properly and updateMapWithResult(); updates all geopoint, so these two methods are ok. Only if I try to invoke this in the inner class the json calls seem to be working but the static variable foundResults is filled with null elements and the program doesn't work properly.
Any suggestion?

I have understand where is the problem.
You have to run the search method on the UI thread.
So change this code block:
#Override
protected Void doInBackground(String... strings) {
try {
search(strings[0], string[1]);
return null;
} catch(Exception e) {
}
}
with this
#Override
protected Void doInBackground(final String... strings) {
try {
runOnUiThread(new Runnable() {
public void run() {
search(strings[0], string[1]);
return null;
}
});
} catch(Exception e) {
e.printStackTrace();
}
}
And all should works correctly.

Here is one problem:
OnClickListener mSearchListener = new OnClickListener() {
public void onClick(View v) {
String Location=editorLocation.getText().toString();
String name=editorName.getText().toString();
//Call the AsyncTask here
new YourCustomAsyncTask().execute(new String[] {name, location});
}
Your Location should be location.
Also here:
#Override
protected Void doInBackground(String... strings) {
try {
search(strings[0], string[1]);
} catch(Exception e) {
}
}
#Override
protected void onPostExecute(Void params) {
updateMapWithResult();
dialog.dismiss();
//result
}
In doInBackground you don't assign a value after you search. You might try this:
#Override
protected Void doInBackground(String... strings) {
try {
search(strings[0], string[1]);
String name = string[0];
String location = string[1]
} catch(Exception e) {
}
}
Or something else that will assign value while it runs. As it is, it appears that you just search, and then nothing else.
The reason foundResults is null is because you don't ever assign it a value.

There is nothing wrong with your AsyncTask. Please include the search() method.