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Android viewpager AsyncTask finish when page changed

I have view pager. My viewpager contains 3 fragments. In the first fragment I have an AsyncTask class. I parsed JSON with AsyncTask and I can show it in listview. (everything is ok)
I have one problem AsyncTask which I have in the first fragment does not finish when I go to the next fragments. When I am in the second fragment my AsyncTask is also running. How can I write code to cancel my AsyncTask when viewpager's page changed?
This is my source (this is the first fragment source; another fragment source is the same but the only difference is the Server Url):
public class StradaChefs1 extends Fragment {
public static CustomerStatistic stat;
private ConnectionDetector con;
private AlertDialogManager alert = new AlertDialogManager();
#SuppressLint("ClickableViewAccessibility")
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.strada_chefs_1, container,
false);
stat = new CustomerStatistic();
con = new ConnectionDetector(getActivity());
if (!con.isConnectingToInternet()) {
alert.showAlertDialog(getActivity(),
"You have not internet connection");
} else {
stat.execute("my urlllllllll"); // geo
}
return rootView;
}
public class CustomerStatistic extends AsyncTask<String, Void, String> {
ProgressDialog pDialog;
#Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = ProgressDialog.show(getActivity(), "Please Wait... ",
"Loading... ");
pDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected String doInBackground(String... params) {
return Utils.getJSONString(params[0]);
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
try {
JSONArray mainJson = new JSONArray(result);
String first = mainJson.getString(0);
JSONObject jobject = new JSONObject(first);
String image = jobject.getString("image");
String String_title = jobject.getString("title");
String String_name = jobject.getString("name");
String String_desc = jobject.getString("description");
String second = mainJson.getString(1);
} catch (JSONException e) {
e.printStackTrace();
}
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
}
#Override
public void onResume() {
Log.e("DEBUG", "onResume of HomeFragment");
super.onResume();
}
#Override
public void onStop() {
super.onStop();
if (stat != null && stat.equals(AsyncTask.Status.RUNNING)) {
stat.cancel(true);
Toast.makeText(getActivity(), "finished", Toast.LENGTH_SHORT)
.show();
}
}
}
This is a viewpager java code
public class TabbedActivity1 extends Fragment {
private StradaChefs1 mfragment1;
private StradaChefs2 mfragment2;
private StradaChefs3 mfragment3;
private StradaChefs4 mfragment4;
SectionsPagerAdapter mSe;
public static final String TAG = TabbedActivity1.class.getSimpleName();
ViewPager mViewPager;
private ArrayList<Fragment> fragmentList;
public static TabbedActivity1 newInstance() {
return new TabbedActivity1();
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_item_one_1, container, false);
mSe=new SectionsPagerAdapter(getChildFragmentManager());
mViewPager = (ViewPager) v.findViewById(R.id.pager1);
CirclePageIndicator circle=(CirclePageIndicator)v.findViewById(R.id.circleindicator1);
mViewPager.setAdapter(mSe);
circle.setViewPager(mViewPager);
mfragment1 = new StradaChefs1();
mfragment2 = new StradaChefs2();
mfragment3 = new StradaChefs3();
mfragment4 = new StradaChefs4();
fragmentList = new ArrayList<Fragment>();
fragmentList.add(mfragment1);
fragmentList.add(mfragment2);
fragmentList.add(mfragment3);
fragmentList.add(mfragment4);
mViewPager.setPageTransformer(false, new PageTransformer() {
#Override
public void transformPage(View page, float position) {
page.setRotationY(position * -40);
}
});
return v;
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
#Override
public int getCount() {
return 4;
}
#Override
public CharSequence getPageTitle(int position) {
return null;
}
}
}
How can I solve this problem?

The FragmentPagerAdapter keeps additional fragments, besides the one shown, in resumed state, so you can't use onPause and onResume for starting/stopping the AsyncTask. The solution is to implement a custom OnPageChangeListener and create a new method for when the fragment is shown.
1) Create LifecycleManager Interface The interface will have two methods and each ViewPager’s Fragment will implement it. These methods Are as follows:
public interface FragmentLifecycle {
public void onPauseFragment();
public void onResumeFragment();
}
2) Let each Fragment implement the interface
3) Implement interface methods in each fragment - in onPauseFragment stop the AsyncTask, in onResumeFragment start it
4) Call interface methods on ViewPager page change You can set OnPageChangeListener on ViewPager and get callback each time when ViewPager shows another page
5) Implement OnPageChangeListener to call your custom Lifecycle methods
Listener knows the new position and can call the interface method on new Fragment with the help of PagerAdapter. I can here call onResumeFragment() for new fragment and onPauseFragment() on the current one.
I need to store also the current fragment’s position (initially the current position is equal to 0), since I don’t know whether the user scrolled from left to right or from right to left. See what I mean in code:
private OnPageChangeListener pageChangeListener = new OnPageChangeListener() {
int currentPosition = 0;
#Override
public void onPageSelected(int newPosition) {
FragmentLifecycle fragmentToShow = (FragmentLifecycle)pageAdapter.getItem(newPosition);
fragmentToShow.onResumeFragment();
FragmentLifecycle fragmentToHide = (FragmentLifecycle)pageAdapter.getItem(currentPosition);
fragmentToHide.onPauseFragment();
currentPosition = newPosition;
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) { }
public void onPageScrollStateChanged(int arg0) { }
};
I didn't write the code. Full tutorial here

When you start the asynctask set the flag isRunning=true
when you are trying to jump from one fragment to other it mean
as per fragment lifecycle your are pausing and stoping your current fragment
so in onStop method of fragment you can check isRunning flag of asynctask is true if yes the
cancel the asyntask
its my logic hope it will help you to achieve your requirement

Video is not pausing in fragment ViewPager

I am using View Pager with fragment to showing image and video, I am able to show image and video properly but I have problem, when I swipe for video, then video is playing, but I swipe next or previous then video is still playing on just next or previous screen but when I move two slide next or previous then video is being stop, but why not on next or previous slide.
I search it more but I did not get any solution, any help will be appreciable.
Thanks in advance.
Here is my code:
This is Fragment Class
public class ContentFragment extends Fragment {
private final String imageResourceId;
private String type;
public ContentFragment(String imageResourceId,String type) {
System.out.println("Path In cons="+imageResourceId+"and type is="+type);
this.imageResourceId = imageResourceId;
this.type= type;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e("Test", "hello");
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.content_layout, container, false);
TouchImageView imageView = (TouchImageView) view.findViewById(R.id.touchImage);
imageView.setImageResource(R.id.touchImage);
imageView.setMaxZoom(10f);
VideoView videoView =(VideoView) view.findViewById(R.id.videoView1);
if(type.equals("image")) {
imageView.invalidate();
imageView.setVisibility(View.VISIBLE);
videoView.setVisibility(View.GONE);
try {
System.out.println("IN Content Fragment"+imageResourceId.toString());
Bitmap bmp = BitmapFactory.decodeFile(imageResourceId.toString());
imageView.setImageBitmap(bmp);
} catch(Exception e) {
System.out.println("Error Of image File"+e);
}
} else
try {
if(type.equals("video")){
videoView.invalidate();
videoView.setVisibility(View.VISIBLE);
imageView.setVisibility(View.GONE);
String path = imageResourceId.toString();
videoView.setVideoURI(Uri.parse(path));
videoView.setMediaController(new MediaController(getActivity()));
videoView.setFocusable(true);
videoView.start();
}
} catch(Exception e) {
e.printStackTrace();
}
return view;
}
}
This is pager adapter activity
public class MediaActivity extends FragmentActivity {
private MyAdapter mAdapter;
private ViewPager mPager;
public ArrayList<Content> contentList;
Context context;
LinearLayout numberOfPageLayout;
SharedPreferences sharedPreferences;
Handler progressHandler;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_media);
context=(Context) getApplicationContext();
mPager = (ViewPager) findViewById(R.id.pager);
progressHandler = new Handler();
contentList=new ArrayList<Content>();
new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
contentList=new ContentDBAdapter(context).getAllContent();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
mAdapter = new MyAdapter(getSupportFragmentManager(),contentList);
mPager.setAdapter(mAdapter);
}
}.execute();
mPager.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageSelected(int arg0) {
// TODO Auto-generated method stub
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// TODO Auto-generated method stub
}
#Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
}
});
}
public static class MyAdapter extends FragmentPagerAdapter {
ArrayList <Content>contList=new ArrayList<Content>();
public MyAdapter(FragmentManager fm,ArrayList<Content> cont) {
super(fm);
this.contList=cont;
}
#Override
public int getCount() {
totalPage=contList.size();
return contList.size();
}
#Override
public Fragment getItem(int position) {
Content con=contList.get(position);
return new ContentFragment(con.getPath(),con.getType());
}
}
}

It is because ViewPager keeps offscreen fragments started. For instance you have a fragment visible to the user. ViewPager will try to keep the previous fragment (on the left side) and the next fragment (on the right side) started. This allows ViewPager performing smooth sliding when user decides to change the page, because the next and the previous pages are already prepared.
In your case the video player is not visible (offscreen), but ViewPager keeps it started as due to the behaviour described above. You can use setOffscreenPageLimit() method to change this behaviour. If you set page limit to 0, then offscreen fragments will be paused immediately. Unfortunately they will not only be paused, but stopped and detached from the activity too. This means when you return back to your fragment, it will recreate the whole layout anew. That's why you can try to override either Fragment.setUserVisibleHint() or Fragment.onHiddenChanged() and execute your pause/play logic there. ViewPager will update hidden state of a fragment depending on whether the fragment is actually visible to user or not.
Hope this helps.

You have to override setUserVisibleHint method in a fragment where u play video.
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (this.isVisible())
{
if (!isVisibleToUser) // If we are becoming invisible, then...
{
//pause or stop video
}
if (isVisibleToUser)
{
//play your video
}
}
}

I handle the problem like this:
boolean isVisible = false;
#Override
public void setUserVisibleHint(boolean isVisibleToUser) {
isVisible = isVisibleToUser;
if(player!=null)
player.pause();
super.setUserVisibleHint(isVisibleToUser);
}
then in onCreateView method:
SimpleExoPlayer player;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_screen_slide_page, container, false);
PlayerView playerView = v.findViewById(R.id.playerView);
playerView.getLayoutParams().width = ListPager.widthPixels;
playerView.getLayoutParams().height = ListPager.widthPixels;
if(player!=null)
player.release();
player = new SimpleExoPlayer.Builder(App.applicationContext).build();
playerView.setPlayer(player);
MediaItem mediaItem = MediaItem.fromUri(url);
player.setMediaItem(mediaItem);
player.prepare();
//---------The following code is important because if you remove the following if
// then if the next page is displaying, android will automatically initiate the
// previous and the next page, and the player will start playing :|
if(isVisible)
player.play();
}

Which is the best way to show a loading sign to the fragment when data loading?

We use viewpager fragment in it, we want to show every single page when viewpager show a fragment and load data , because it saves memory a lot, but we can not show a sign for loading when data loading, we replace a fragment when asynctask's onPreExecute calls and we replace again when calls onPostExecute, but there is some thing wrong, which is the best way to show loading sign when data loading?
public class TestFragment extends Fragment {
private FragmentManager manager = null;
private class TestTask extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
getFragmentManager().beginTransaction()
.replace(R.id.content_container, new LoadingFragment())
.commit();
super.onPreExecute();
}
#Override
protected Void doInBackground(Void... arg0) {
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
getFragmentManager().beginTransaction()
.replace(R.id.content_container, new ContentFragment())
.commit();
super.onPostExecute(result);
}
}
public TestFragment(FragmentManager supportFragmentManager) {
this.manager = supportFragmentManager;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new TestTask().execute();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.empty_page, null);
}
}

Another easy way if you use the action bar in your app is calling supportRequestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS); in the FragmentActivity right after super.onCreate(savedInstanceState); and from the child fragment ((ActionBarActivity)getActivity()).setSupportProgressBarIndeterminateVisibility(visibility); will show or hide a progress bar in the action bar of your hosting activity depending on your progress in the AsyncTask.
Note: I'm using support appcompat, but I'm pretty sure the methods are the same if you use ActionBarSherlock.

add an progressbar to the layout of the fragment but defining it invisible and centering it both vertically and horizontally. then in the onPreExecute set the visibility of all other views to Visibility.GONE and set the progressbar to VISIBLE. reverse this in the onPostExecute() method!

multiple layout viewpager with one fragment

I must clear that I am looking for an example or answer where I can use various differnt layout designs in a viewpager and the data in all the pages would be dynamic and all pages can be interacted by the user.
My Use Case and current approach towards the problem :
So I have got 8 different types of question types and so I have created layouts for all of them. Also I the data in the views for these layouts has to be populated via java Map that has fetched data from the sqlite DB.
But a test may contain 25 questions with different layouts out of the above 8. And for all these 25 questions I want to use a Viewpager and a Fragment that will return the required layout based on the passed question type value out of my java map.
My apporach towards this :
I have created an activity and have inflated it with a viewpager layout :
R.layout.practice_pager
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/test_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
*Activity Edited code *
public class TestActivity extends FragmentData implements FragmentData{
FragmentManager manager=getSupportFragmentManager();
private ViewPager mViewPager;
private MyFragmentPagerAdapter mMyFragmentPagerAdapter;
int PAGE_COUNT = 0;
GrePracticeTestRecord p=new GrePracticeTestRecord();
private HashMap<Integer, GrePracticeResultRecord> mPracResultMap;
public static int fragmentToReturn=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.practice_pager);
mViewPager = (ViewPager) findViewById(R.id.test_container);
//This function is called to fetch the data from sqlite db and fill the map with data
LoadingTestView();
PAGE_COUNT=mPracRecordMap.size();
initPager();
}
//here I initialize the pager and set the adapter to it
public void initPager()
{
p.setQUES(mPracRecordMap.get(1).getQUES());
p.setEXPL(mPracRecordMap.get(1).getEXPL());
fragmentToReturn=Integer.parseInt(mPracRecordMap.get(1).getQTYPE());
setData(p);
mMyFragmentPagerAdapter = new MyFragmentPagerAdapter(getSupportFragmentManager(),fList);
mViewPager.setAdapter(mMyFragmentPagerAdapter);
mViewPager.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageSelected(int arg0) {
mMyFragmentPagerAdapter.notifyDataSetChanged();
p.setQUES(mPracRecordMap.get(mViewPager.getCurrentItem()+1).getQUES());
p.setEXPL(mPracRecordMap.get(mViewPager.getCurrentItem()+1).getEXPL());
setData(p);
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
});
}
#Override
public void setData(GrePracticeTestRecord p) {
// TODO Auto-generated method stub
}
#Override
public GrePracticeTestRecord getData() {
// TODO Auto-generated method stub
return p;
}
}
My Adapter Edited code
public class MyFragmentPagerAdapter extends FragmentStatePagerAdapter{
private List<Fragment> fragments;
public MyFragmentPagerAdapter(FragmentManager fm,List<Fragment> fragments) {
super(fm);
this.fragments = fragments;
}
/** This method will be invoked when a page is requested to create */
#Override
public Fragment getItem(int position) {
System.out.println("value of position "+position);
return this.fragments.get(position);
}
/** Returns the number of pages */
#Override
public int getCount() {
return this.fragments.size();
}
#Override
public int getItemPosition(Object object) {
// TODO Auto-generated method stub
return MyFragmentPagerAdapter.POSITION_NONE;
}
}
Interface FragmentData
public interface FragmentData {
public void setData(GrePracticeTestRecord p);
public GrePracticeTestRecord getData();
}
TestFragment Edited code
public class TestFragment extends Fragment {
AnswerEnterListener callBack;
FragmentData fD;
Button submitAnswer;
EditText userAnswer;
TextView qText,expl;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.qtype1, container, false);
}
public interface AnswerEnterListener
{
public void onInputAnswer(String ans);
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
callBack=(AnswerEnterListener) activity;
fD=(FragmentData) activity;
} catch (Exception e) {
// TODO: handle exception
}
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
qText=(TextView) getActivity().findViewById(R.id.question_text);
expl=(TextView)getActivity().findViewById(R.id.explanation_text);
qText.setText(Html.fromHtml(fD.getData().getQUES()));
expl.setText(Html.fromHtml(fD.getData().getEXPL()));
}
}
Similar to TestFragment , I have not the other fragments too. Each for a layout type.
Issues :
The first layout is repeated two times at the first time , and also when I swipe back then the position of data is misplaced.
Is this the right approach, I have been suggested by someone that you should use three fragments and update the left and right fragments with data , but this actually bounced off me. Can anyone share a good example of it or a blog.

I must clear that I am looking for an example or answer where I can
use various differnt layout designs in a viewpager and the data in all
the pages would be dynamic and all pages can be interacted by the
user.
This should be quite easy to make but you seem to have complicated this a lot. You need to do something like this:
Get the data from the database with the LoadingTestView(); function.
Initialize the ViewPager and set it's adapter. The adapter will return the proper fragment instance in the getItem() method, based on whatever criteria you have.
In the fragments, retrieve the data from the activity which should expose the data through some method.
I've made a simple example that you can find here.

run onresume() method when i change tab "ontabchange()" in a view

I put the code in onResume() method for it to run each time when i load it again by tab click but problem is now that data load first time from server in to list view when I click first time on tab and when I change the tab and load it again it force close and gives "array index out of bound exception". I think it is because it not removes previous loaded data and so how to remove or reload new data on tab click so that exception not occur? This means before loading new data via onResume() how to delete old data?
protected void onPause() {
super.onPause();
}
protected void onResume()
{
super.onResume();
**new ProgressTask6().execute();**
}
private class ProgressTask6 extends AsyncTask<String, Void, Boolean> {
private ProgressDialog dialog;
private Context context;
#Override
protected void onPreExecute() {
dialog = new ProgressDialog(OpeningToday.this);
dialog.setMessage("Processing...");
dialog.setIndeterminate(true);
dialog.setCancelable(false);
dialog.show();
}
#Override
protected void onPostExecute(final Boolean success) {
if (dialog.isShowing())
{
dialog.dismiss();
setListAdapter(new MyAdapter(OpeningToday.this));
}
}
#Override
protected Boolean doInBackground(String... args) {
try{
} catch (Exception e){
Log.e("tag", "error", e);
return false;
}
return null;
}
class MyAdapter extends BaseAdapter implements OnClickListener
{
}
#Override
public int getCount() {
} }
/* Not implemented but not really needed */
#Override
public Object getItem(int position) {
return null;
}
/* Not implemented but not really needed */
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(int position, View ConvertView, ViewGroup parent)
{
View v = inflater.inflate(R.layout.listitem_layout, parent, false);
// Log.i("array galoijewdh..",keywordresulttab.array_galleryname[position]);
Log.i("saurabh trivedi","saurabh trivedui");
// Variables.a=3;
String gallerynames = keywordresulttab.array_galleryname[position];
String addresses = keywordresulttab.array_address[position];
TextView tv = (TextView) v.findViewById(R.id.barrio);
tv.setText(gallerynames);
tv = (TextView) v.findViewById(R.id.ciudad);
tv.setText(addresses);
((BaseAdapter)(getListAdapter())).notifyDataSetChanged();
return v;
}
#Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
}
}

Initialize the index / delete data in onPause() which is the opposite of onResume().
As a rule of thumb (according to activity lifecycle) - clean what you need in the opposite method -
onCreate() - onDestroy()
onStart() / onRestart() - onStop()
onResume() - onPause()