In the OnCreate method, I have invoked 3 AsyncTask which basically fills data for the 3 Spinners. What I need is that I should have the Login button disabled till all 3 tasks finish. How can I achieve that ?
new SpinnerDataFetcher("GetFreeDrivers1",(Spinner)findViewById(R.id.Spinner_1)).execute();
new SpinnerDataFetcher("GetFreeDrivers2",(Spinner)findViewById(R.id.Spinner_2)).execute();
new SpinnerDataFetcher("GetFreeDrivers3",(Spinner)findViewById(R.id.Spinner_3)).execute();
Just increment a number that corresponds on how many AsyncTask are done.
int s = 0;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new SpinnerDataFetcher(){
#Override
protected void onPostExecute(....) {
super.onPostExecute(...);
s++;
check();
}
}.execute();
new SpinnerDataFetcher(){
#Override
protected void onPostExecute(....) {
super.onPostExecute(...);
s++;
check();
}
}.execute();
new SpinnerDataFetcher(){
#Override
protected void onPostExecute(....) {
super.onPostExecute(...);
s++;
check();
}
}.execute();
}
public void check(){
if(s >=3){
s= 0;
// enable button here
}
}
Initialize your AsyncTask instance with a reference to the Activity/Fragment that creates it. Then signal back in onPostExecute when its done
e.g.
class Spinner1DataFetcher extends AsyncTask<...> {
public Spinner1DataFetch(YourActivityOrFragment activity) {
_activity = activity;
}
protected void onPostExecute(...) {
_activity.spinner_1_is_done();
}
}
For that you have to Disable Button before calling new Spinner1DateFetcher and call Second from Spinner1DateFetcher method onPostExecute and same as Third Spinner method and in Third Spinner onPostExecute set Button to Enable..
For Disable Button use
Button.setEnabled(false);
and For Enable Button use
Button.setEnabled(true);
Edit :
for the parameter check you have to add Constuctor and check the condition like below way.
private class MyAsyncTask extends AsyncTask<Void, Void, Void> {
public MyAsyncTask(boolean showLoading) {
super();
// do stuff
}
// doInBackground() et al.
}
There are multiple ways how you can achieve this.
The straightforward way to implement this is create a counter which will trigger UI update.
final InterfaceTrigger trigger = new InterfaceTrigger();
new AsyncTask<>() {
#Override
protected void onPostExecute(Object o) {
super.onPostExecute(o);
trigger.finishJob();
if (trigger.isTimeToUpdateUi()) {
// TODO update your UI
}
}
};
public class InterfaceTrigger {
private static final int THRESHOLD = 3;
private int counter;
public synchronized void finishJob() {
counter++;
}
public synchronized boolean isTimeToUpdateUi() {
return counter == THRESHOLD;
}
}
Another way is to use CyclicBarier and ExcutorService mechanism.
Related
I have a value more than 1, so I planned to make a for loop to execute for each value. The problem is the for loop is looping/continue even the AsyncTask is not finish yet.
AsyncTask Class
public class Server extends AsyncTask<JSONObject, Void, Void> {
#Override
protected Void doInBackground(JSONObject... params) {
.........
}
#Override
protected void onPostExecute(Void result) {
.........
}
}
Activity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_a);
for(int i=0; i<10; i++){
Server myServer = new Server();
myServer.execute(i);
}
}
As #cricket_007 commented, the loop won't wait as AsyncTask is asynchronous and hence the loop continues without waiting for the AsyncTask to finish. So as I've understood your purpose, you need to do something like this.
You need define an interface like this.
public interface ResponseListener {
void responseReceiver();
}
Now modify your AsyncTask like this
public class Server extends AsyncTask<JSONObject, Void, Void> {
public ResponseListener responseListener;
#Override
protected Void doInBackground(JSONObject... params) {
// .........
}
#Override
protected void onPostExecute(Void result) {
// ......... Other code
// Now here's the callback function to the main activity.
responseListener.responseReceiver();
}
}
Now from your activity you need to do something like this.
public class YourActivity extends Activity implements HttpResponseListener {
public int count = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_a);
Server myServer = new Server();
myServer.responseListener = this;
myServer.execute(i);
}
// Callback method implementation
#Override
public void responseReceiver() {
// This is the callback function and it gets called when one AsyncTask finishes.
// Increase the count here and keep track of how many times the AsyncTask has been executed.
// Do something
count++;
// Now call the next AsyncTask again if the count haven't reach 10 already
if(count <= 10) {
Server myServer = new Server();
myServer.responseListener = this;
myServer.execute(i);
}
}
}
Hope that helps.
My solution is a bit of a long shot, but does the job I suppose.
static Boolean ASYNC_TASK_FINISHED;
for(int i=0; i<10; i++){
ASYNC_TASK_FINISHED = false;
Server myServer = new Server();
myServer.execute(i);
while(!ASYNC_TASK_FINISHED){ }
}
Then in your AsyncTask
#Override
protected void onPostExecute(Void result) {
...
ASYNC_TASK_FINISHED = true;
}
You should make the ASYNC_TASK_FINISHED variable a global singleton one thats accessible by both Activity and AsyncTask.
I don't want to implement an interface directly in asynctask class like this:
new AsyncTask<Void, Void, Void>() {
#Override
protected void onPreExecute() {
super.onPreExecute();
swipeRefreshLayout.setRefreshing(true);
}
#Override
protected Void doInBackground(Void... params) {
retrofitCallBackUtil.getLastTenMessageCallBack(AppConfig.USER_ID, userId, offsetNumber, service, new RetrofitResponseCallBack() {
#Override
public void onSuccess(ArrayList<Message> messages) {
messageAdapter.insertToTheFirst(messages);
}
#Override
public void onFailure() {
}
});
offsetNumber += 5;
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
messageAdapter.notifyDataSetChanged();
swipeRefreshLayout.setRefreshing(false);
}
}.execute();
I just to implement it by main class and put this into this parameter like this:
retrofitCallBackUtil.getLastTenMessageCallBack(AppConfig.USER_ID, userId, offsetNumber, service, this);
but I cannot do it inside asynctask method. So anyone can give me some solution?
I assume you have these code in MainActivity (or something similar).
Let's implement the interface you need to pass into getLastTenMessageCallBack in this Activity by implements RetrofitResponseCallBack {...}
Now, in your Asyntask doInBackground method, call
retrofitCallBackUtil.getLastTenMessageCallBack(AppConfig.USER_ID, userId, offsetNumber, service, MainActivity.this)
Voila, you don't have to create anonymous class inside your Asyntask anymore.
Note that, you have to move and place the fields/params properly, just the matter of being right place, no big deal :D
Create a class separately for AsyncTask like this. This AsyncTask will process the data and publish the data who implements the interface defined inside the AsyncTask . In this case interface defined is DataDownloadListener
public class GetFoldersAsync extends AsyncTask<Integer,Boolean,Boolean> {
Context context;
ProgressDialog dialog;
ArrayList mFolderDataLevel;
public GetFoldersAsync(Context context){
this.context=context;
}
public static interface DataDownloadListener {
public void dataDownloadedSuccessfully(ArrayList data);
public void dataDownloadFailed();
}
DataDownloadListener dataDownloadListener;
public void setDataDownloadListener(DataDownloadListener dataDownloadListener) {
this.dataDownloadListener = dataDownloadListener;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
dialog = ProgressDialog.show(context, "Please wait", "Processing.........");
}
#Override
protected Boolean doInBackground(Integer... params) {
Log.v(Constants.BLL_LOG, "ExplorerDBOperation doInBackground ");
mFolderDataLevel=new ArrayList();
// Process to populate mFolderDataLevel
return true;
}
#Override
protected void onPostExecute(Boolean aBoolean) {
super.onPostExecute(aBoolean);
if(dialog!=null && dialog.isShowing())
{dialog.dismiss();}
Log.v(Constants.BLL_LOG, "ExplorerDBOperation onPostExecute ");
if(mFolderDataLevel!=null && mFolderDataLevel.size()>0){
dataDownloadListener.dataDownloadedSuccessfully(mFolderDataLevel);
}else{
dataDownloadListener.dataDownloadFailed();
}
}
}
Now in the caller Activity, call this method when the AsyncTask needs to process and get back data to same activity.
public class HomeActivity extends AppCompatActivity {
//Other necessary methods goes here .....
//call this method for processing AsyncTask and to get back data
public void getFolderData(int parentID, int callerID){
Log.v(Constants.BLL_LOG,"parentID="+parentID+" , callerID="+callerID);
mCallerID=callerID;
GetFoldersAsync getFolders = new GetFoldersAsync(this);
getFolders.setDataDownloadListener(new GetFoldersAsync.DataDownloadListener()
{
#SuppressWarnings("unchecked")
#Override
public void dataDownloadedSuccessfully(ArrayList data) {
Log.v(Constants.BLL_LOG,"getFolderData dataProcessSuccessfully");
// Success data with populated ArrayList to process further
}
#Override
public void dataDownloadFailed() {
//Failure
Log.v(Constants.BLL_LOG,"getFolderData dataProcessFailed()");
}
});
getFolders.execute(callerID);
}
}
I have an AsyncTask where I make request to server and download some data. And according to received data I start Activity A or Activity B in onPostExecute().
The problem is that doesn't work. No errors, simply activity doesn't start. Seems like code isn't executed there at all.
private class LoadingAsyncTask extends AsyncTask<Boolean, Void, Boolean> {
protected Void doInBackground(Boolean... params) {
if (InternetConnection.isConnected(ActivityLoading.this)) {
.....load data
} else {
Toast.makeText(ActivityLoading.this, getString(R.string.no_internet_connection), Toast.LENGTH_SHORT).show();
}
isDone = true;
return isDone;
}
protected void onPostExecute(Void isDone) {
super.onPostExecute(isDone);
//if work is done
if (isDone) {
if (dwnlData.equals("success")) {
getApplicationContext().startActivity(new Intent(ActivityLoading.this, ActivityNavigation.class));
} else {
getApplicationContext().startActivity(new Intent(ActivityLoading.this, ActivityAuthorization.class));
}
}
}
I call AsyncTask in onCreate:
public class ActivityLoading extends ActionBarActivity {
static boolean isDone = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_loading);
new LoadingAsyncTask().execute();
}
Change the argument data type void to boolean
protected void onPostExecute(boolean isDone) {
super.onPostExecute(isDone);
//if work is done
if (isDone) {
if (dwnlData.equals("success")) {
getApplicationContext().startActivity(new Intent(ActivityLoading.this, ActivityNavigation.class));
} else {
getApplicationContext().startActivity(new Intent(ActivityLoading.this, ActivityAuthorization.class));
}
}
Did you try making isDone a boolean?
Edit - You could just make doInBackground return nothing, and stop using the argument in onPostExecute.
I suggest using Log.d() or Toast() inside those if{} blocks to verify that your conditions are true
I have spent many hours looking for a solution to this and need help.
I have a nested AsyncTask in my Android app Activity and I would like to allow the user to rotate his phone during it's processing without starting a new AsyncTask. I tried to use onRetainNonConfigurationInstance() and getLastNonConfigurationInstance().
I am able to retain the task; however after rotation it does not save the result from onPostExecute() to the outer class variable. Of course, I tried getters and setters. When I dump the variable in onPostExecute, that it is OK. But when I try to access to the variable from onClick listener then it is null.
Maybe the code will make the problem clear for you.
public class MainActivity extends BaseActivity {
private String possibleResults = null;
private Object task = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.task = getLastNonConfigurationInstance();
setContentView(R.layout.menu);
if ((savedInstanceState != null)
&& (savedInstanceState.containsKey("possibleResults"))) {
this.possibleResults = savedInstanceState
.getString("possibleResults");
}
if (this.possibleResults == null) {
if (this.task != null) {
if (this.task instanceof PossibleResultWebService) {
((PossibleResultWebService) this.task).attach();
}
} else {
this.task = new PossibleResultWebService();
((PossibleResultWebService) this.task).execute(this.matchToken);
}
}
Button button;
button = (Button) findViewById(R.id.menu_resultButton);
button.setOnClickListener(resultListener);
}
#Override
protected void onResume() {
super.onResume();
}
OnClickListener resultListener = new OnClickListener() {
#Override
public void onClick(View v) {
Spinner s = (Spinner) findViewById(R.id.menu_heatSpinner);
int heatNo = s.getSelectedItemPosition() + 1;
Intent myIntent = new Intent(MainActivity.this,
ResultActivity.class);
myIntent.putExtra("matchToken", MainActivity.this.matchToken);
myIntent.putExtra("heatNo", String.valueOf(heatNo));
myIntent.putExtra("possibleResults",
MainActivity.this.possibleResults);
MainActivity.this.startActivityForResult(myIntent, ADD_RESULT);
}
};
private class PossibleResultWebService extends AsyncTask<String, Integer, Integer> {
private ProgressDialog pd;
private InputStream is;
private boolean finished = false;
private String possibleResults = null;
public boolean isFinished() {
return finished;
}
public String getPossibleResults() {
return possibleResults;
}
#Override
protected Integer doInBackground(String... params) {
// quite long code
}
public void attach() {
if (this.finished == false) {
pd = ProgressDialog.show(MainActivity.this, "Please wait...",
"Loading data...", true, false);
}
}
public void detach() {
pd.dismiss();
}
#Override
protected void onPreExecute() {
pd = ProgressDialog.show(MainActivity.this, "Please wait...",
"Loading data...", true, false);
}
#Override
protected void onPostExecute(Integer result) {
possibleResults = convertStreamToString(is);
MainActivity.this.possibleResults = possibleResults;
pd.dismiss();
this.finished = true;
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (this.possibleResults != null) {
outState.putString("possibleResults", this.possibleResults);
}
}
#Override
public Object onRetainNonConfigurationInstance() {
if (this.task instanceof PossibleResultWebService) {
((PossibleResultWebService) this.task).detach();
}
return (this.task);
}
}
It is because you are creating the OnClickListener each time you instantiate the Activity (so each time you are getting a fresh, new, OuterClass.this reference), however you are saving the AsyncTask between Activity instantiations and keeping a reference to the first instantiated Activity in it by referencing OuterClass.this.
For an example of how to do this right, please see https://github.com/commonsguy/cw-android/tree/master/Rotation/RotationAsync/
You will see he has an attach() and detach() method in his RotationAwareTask to solve this problem.
To confirm that the OuterClass.this reference inside the AsyncTask will always point to the first instantiated Activity if you keep it between screen orientation changes (using onRetainNonConfigurationInstance) then you can use a static counter that gets incremented each time by the default constructor and keep an instance level variable that gets set to the count on each creation, then print that.
Update1
activity:
public Integer _number = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
if (_number >0)
{
Log.d("onSuccessfulExecute", ""+_number);
}
else
{
Log.d("onSuccessfulExecute", "nope empty songs lists");
}
}
public int onSuccessfulExecute(int numberOfSongList) {
_number = numberOfSongList;
if (numberOfSongList >0)
{
Log.d("onSuccessfulExecute", ""+numberOfSongList);
}
else
{
Log.d("onSuccessfulExecute", "nope empty songs lists");
}
return numberOfSongList;
}
end Update1
UPDATE: AsynchTask has its own external class.
How to pass an value from AsyncTask onPostExecute()... to activity
my code does returning value from onPostExecute() and updating on UI but i am looking for a way to set the activity variable (NumberOfSongList) coming from AsynchTask.
AsyncTask class:
#Override
public void onPostExecute(asynctask.Payload payload)
{
AsyncTemplateActivity app = (AsyncTemplateActivity) payload.data[0];
//the below code DOES UPDATE the UI textView control
int answer = ((Integer) payload.result).intValue();
app.taskStatus.setText("Success: answer = "+answer);
//PROBLEM:
//i am trying to populate the value to an variable but does not seems like the way i am doing:
app.NumberOfSongList = payload.answer;
..............
..............
}
Activity:
public Integer NumberOfSongList;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Several UI Code
new ConnectingTask().execute();
Log.d("onCreate", ""+NumberOfSongList);
}
What about using a setter method? e.g.
private int _number;
public int setNumber(int number) {
_number = number;
}
UPDATE:
Please look at this code. This will do what you're trying to accomplish.
Activity class
public class TestActivity extends Activity {
public int Number;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
Button btnDisplay = (Button) findViewById(R.id.btnDisplay);
btnDisplay.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Toast toast = Toast.makeText(v.getContext(), "Generated number: " + String.valueOf(Number), Toast.LENGTH_LONG);
toast.show();
}
});
new TestTask(this).execute();
}
}
AsyncTask class
public class TestTask extends AsyncTask<Void, Void, Integer> {
private final Context _context;
private final String TAG = "TestTask";
private final Random _rnd;
public TestTask(Context context){
_context = context;
_rnd = new Random();
}
#Override
protected void onPreExecute() {
//TODO: Do task init.
super.onPreExecute();
}
#Override
protected Integer doInBackground(Void... params) {
//Simulate a long-running procedure.
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
Log.e(TAG, e.getMessage());
}
return _rnd.nextInt();
}
#Override
protected void onPostExecute(Integer result) {
TestActivity test = (TestActivity) _context;
test.Number = result;
super.onPostExecute(result);
}
}
Just a word of caution: Be very careful when attempting to hold a reference to an Activity instance in an AsyncTask - I found this out the hard way :). If the user happens to rotate the device while your background task is still running, your activity will be destroyed and recreated thus invalidating the reference being to the Activity.
Create a listener.
Make a new class file. Called it something like MyAsyncListener and make it look like this:
public interface MyAsyncListener() {
onSuccessfulExecute(int numberOfSongList);
}
Make your activity implement MyAsyncListener, ie,
public class myActivity extends Activity implements MyAsyncListener {
Add the listener to the constructor for your AsyncTask and set it to a global var in the Async class. Then call the listener's method in onPostExecute and pass the data.
public class MyCustomAsync extends AsyncTask<Void,Void,Void> {
MyAsyncListener mal;
public MyCustomAsync(MyAsyncListener listener) {
this.mal = listener;
}
#Override
public void onPostExecute(asynctask.Payload payload) {
\\update UI
mal.onSuccessfulExecute(int numberOfSongList);
}
}
Now, whenever your AsyncTask is done, it will call the method onSuccessfulExecute in your Activity class which should look like:
#Override
public void onSuccessfulExecute(int numberOfSongList) {
\\do whatever
}
Good luck.