Main activity variable becoming null - android

In my main activity I have:
private DataManager mDataManager;
In the same activity I manage this variable following the lifecycle. These are the related methods:
public class MainActivity extends AppCompatActivity {
#Override
public void onStart() {
super.onStart();
mDataManager = new DataManager(this);
}
#Override
public void onResume() {
super.onResume();
mDataManager.connect(getIpAddress());
}
#Override
public void onPause() {
super.onPause();
mDataManager.disconnect();
}
#Override
public void onStop() {
super.onStop();
mDataManager = null;
}
#Override
public DataManager getDataManager() {
return mDataManager;
}
#Override
public void updateFragments() {
runOnUiThread(new Runnable() {
#Override
public void run() {
if (mLoading.isShowing())
mLoading.dismiss();
List<Fragment> allFragments = getSupportFragmentManager().getFragments();
if (allFragments == null || allFragments.isEmpty())
return;
for (Fragment fragment : allFragments)
if (fragment.isVisible())
((UpdatableFragment) fragment).updateView();
}
});
}
I have some fragments that use getDataManager() to update themselves with data, but sometimes, often when I do not use the application for a while I get a nullpointerexception because getDataManager() returned null. According to the activity lifecycle, the object should never be null or am I missing something?
EDIT: Initialization of the ViewPager
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
MainAdapter adapter = new MainAdapter(getSupportFragmentManager());
ViewPager viewPager = (ViewPager) findViewById(R.id.my_pager);
viewPager.setAdapter(adapter);
}
public class MainAdapter extends FragmentPagerAdapter {
MainAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return FragmentX.newInstance();
case 1:
return FragmentY.newInstance();
case 2:
return FragmentZ.newInstance();
case 3:
return FragmentU.newInstance();
}
return null;
}
#Override
public int getCount() {
return 4;
}
}

Related

How to pass arraylist from fragment to fragment using Activity in Android? [duplicate]

This question already has answers here:
Passing ArrayList from Fragment class to Activity
(2 answers)
Closed 5 years ago.
please give me good solution I need your help!.
I want to pass parameter using Interface class
from B Fragment to Activity and from Activity to C Fragment.
But Service asynctask I don't know C waiting for B ?
Please explain me this Fragments do what ?
EDIT:
public class FeedDetailActivity extends AppCompatActivity implements TabFragment_DetailFeed.ArrayPasser {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
String nameSurname;
int feedId;
public ArrayList<String> pathimg;
Bundle bundle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_feeddetail);
// toolbar = (Toolbar) findViewById(R.id.toolbar);
// setSupportActionBar(toolbar);
// getSupportActionBar().setDisplayHomeAsUpEnabled(true);
nameSurname = getIntent().getStringExtra("nameSurname");
Intent i = getIntent();
feedId = i.getIntExtra("feedId",0); // 20 for default value
// feedId = getIntent().getStringExtra("feedId"); // Hata burda
viewPager = (ViewPager) findViewById(R.id.pager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.setupWithViewPager(viewPager);
/* TabFragment_DetailComment EditTextinden otomatik klavye açtırmasını kapatmasını sağlıyor. */
getWindow().setSoftInputMode(
WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN
);
}
public String getNameSurname() {
return nameSurname;
}
public int getFeedId() {
return feedId;
}
private void setupViewPager(ViewPager viewPager) {
FeedDetailActivity.ViewPagerAdapter adapter = new FeedDetailActivity.ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new TabFragment_DetailFeed(), "DETAIL");
adapter.addFragment(new TabFragment_DetailComment(), "COMMENT");
adapter.addFragment(new TabFragment_DetailImage(), "IMAGE");
adapter.addFragment(new TabFragment_DetailSurvey(), "SURVEY");
viewPager.setAdapter(adapter);
}
#Override
public void sendArray(ArrayList<String> strings) {
TabFragment_DetailImage frag = (TabFragment_DetailImage)
getSupportFragmentManager().findFragmentById();
frag.method(strings);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
You should try to use EventBus. With it you can register receivers in your fragments and post events from any part of code.
Here is a little example for your fragments:
In C fragment override onResume() and onPause() like this
#Override
public void onResume() {
super.onResume();
EventBus.getDefault().register(this);
}
#Override
public void onPause() {
super.onPause();
EventBus.getDefault().unregister(this);
}
And also subscribe to your event (you need to create class for it)
#Subscribe(threadMode = ThreadMode.MAIN)
public void onResult(OnResultEvent event) {
//do stuff in event
}
Then in B fragment do like this
public void doStuff(){
//do stuff here
EventBus.getDefault().post(new OnResultEvent(result));
}
You Activity implements your interface(ArrayPasser) in this case which is defined in FragmentA
public class YourActivity implements FragmentA.ArrayPasser{
#Override
public void sendArray(ArrayList<String> strings){
// Get instance of Fragment B using FragmentManager
FraB frag = (FragB)
getSupportFragmentManager().findFragmentById(R.id.fragment_b);
frag.someMethod(strings); //passing arraylist to Fragment B from
Activity
}
}
// Fragment A defines an Interface, and calls the method when needed
public class FragA extends Fragment{
ArrayPasser mCallback; //interface reference
public interface ArrayPasser{
public void sendArray(ArrayList<String> strings);
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception
try {
mCallback = (ArrayPasser) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement ArrayPasser");
}
}
public void someMethod(ArrayList<String>strings){
mCallback.sendArray(strings); //passing array list to fragment
}
#Override
public void onDetach() {
mCallback = null; // => avoid leaking
super.onDetach();
}
}
// Fragment B has a public method to do something with the Array
public class FragB extends Fragment{
public void method(ArrayList<String> strings){
// Here you have it
}
}

Blank fragment after activity recreated

I have an Activity with a ViewPager and TabLayout. I enabled "destroy activities" from Settings in my phone to simulate low memory.
I use getSupportFragmentManager because it's an Activity.
The first time I open the activity, I see my fragments. When I minimize my app and reopen it, I see the tabs but not the content. Inside fragments I call setRetainInstance(true).
Of course if I call super.onCreate(null); instead of super.onCreate(savedInstanceState); it's working fine because the activity is being recreated at all.
If I use FragmentStatePagerAdapter the content is ok but the menu displays duplicated items.
So please, don't suggest FragmentStatePagerAdapter (want all fragments visible), getChildFragmentManager (ViewPager is in an Activity), setRetainInstance (already using it).
public class SystemActivity extends LoadingActivity {
#BindView(R.id.pager)
ViewPager viewPager;
#BindView(R.id.tab_layout)
TabLayout tabLayout;
#BindView(R.id.toolbar)
Toolbar toolbar;
int[] ICONS = {
R.drawable.ic_tab_general,
R.drawable.ic_tab_details
};
int[] TEXTS = {
R.string.general,
R.string.details,
};
private CustomPagerAdapter customPagerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
fetch();
}
protected void fetch() {
super.fetch();
final Long systemId = getIntent().getLongExtra(Constants.Intent.SYSTEM_ID, 0);
this.realm = Realm.getDefaultInstance();
this.call = ApiClientHelper.getInstance(this).getSystem(systemId);
call.enqueue(new ApiUICallback<System>(this) {
#Override
public void onError(int code, String message) {
System system = realm.where(System.class).equalTo("id", systemId).findFirst();
if (system == null) {
fail();
} else {
init(system);
}
}
#Override
public void onSuccess(System system) {
realm.beginTransaction();
realm.copyToRealmOrUpdate(system);
realm.commitTransaction();
init(system);
}
});
}
private void init(System system) {
setContentView(R.layout.activity_system);
ButterKnife.bind(this);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
customPagerAdapter = new CustomPagerAdapter(getSupportFragmentManager(), system);
viewPager.setOffscreenPageLimit(TEXTS.length);
viewPager.setAdapter(customPagerAdapter);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);
CharSequence title = customPagerAdapter.getPageTitle(0);
getSupportActionBar().setTitle(title);
for (int i = 0; i < ICONS.length; i++) {
TabLayout.Tab tab = tabLayout.getTabAt(i);
tab.setCustomView(R.layout.tab_view);
((ImageView) tab.getCustomView().findViewById(R.id.icon)).setImageResource(ICONS[i]);
}
tabLayout.setOnTabSelectedListener(
new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
CharSequence title = customPagerAdapter.getPageTitle(tab.getPosition());
getSupportActionBar().setTitle(title);
hiddenKeyboard();
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
hiddenKeyboard();
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
hiddenKeyboard();
}
}
);
}
private void hiddenKeyboard() {
View focus = getCurrentFocus();
if (focus != null) {
focus.clearFocus();
InputMethodManager keyboard = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
keyboard.hideSoftInputFromWindow(focus.getWindowToken(), 0);
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
finish();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
class CustomPagerAdapter extends FragmentPagerAdapter {
private System system;
public CustomPagerAdapter(FragmentManager fm, System system) {
super(fm);
this.system = system;
}
#Override
public Fragment getItem(int position) {
Fragment fragment;
switch (position) {
case 0:
fragment = new SystemGeneralFragment();
break;
case 1:
fragment = new SystemDetailsFragment();
break;
default:
return null;
}
Bundle bundle = new Bundle();
bundle.putLong(Constants.Intent.SYSTEM_ID, this.system.getId());
fragment.setArguments(bundle);
return fragment;
}
#Override
public int getCount() {
return TEXTS.length;
}
#Override
public CharSequence getPageTitle(int position) {
return getResources().getString(TEXTS[position]);
}
}
}
And one of my fragments:
public class SystemGeneralFragment extends MyFragment {
#BindView(R.id.progress)
View progress;
#BindView(R.id.progress_background)
View progressBackground;
#BindView(R.id.progress_percentage)
TextView percentage;
protected Call call;
protected Realm realm;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
realm = Realm.getDefaultInstance();
}
#Override
public void onDestroyView() {
if (this.call != null) {
this.call.cancel();
}
super.onDestroyView();
}
#Override
public void onDestroy() {
realm.close();
super.onDestroy();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_system_general, container, false);
ButterKnife.bind(this, view);
System system = realm.where(System.class).equalTo("id", getArguments().getLong(Constants.Intent.SYSTEM_ID)).findFirst();
System.Status status = system.getStatus();
percentage.setText(String.format("%d%%", status.getProgress()));
setProgress(progress, status.getColor(getContext()));
setProgress(progressBackground, ContextCompat.getColor(getContext(), R.color.light_gray));
return view;
}
private void setProgress(View view, int color) {
GradientDrawable shape = new GradientDrawable();
shape.setCornerRadius(16);
shape.setColor(color);
if (Build.VERSION.SDK_INT >= 16) {
view.setBackground(shape);
} else {
view.setBackgroundDrawable(shape);
}
}
}

Android Fragment with attached AsyncTask gives null after commit in Activity

I try to understand basic design pattern behind implementing AsyncTask and attaching it to Fragment. I follow numerous tutorials and implemented code (which gives nothing):
1) my Fragment class which contains AsyncTask:
public class MyFragment extends Fragment
{
public interface TaskCallback
{
void onPreExecute();
void onProgressUpdate(Integer... i);
void onPostExecute();
}
private TaskCallback mCallback;
private Task mTask;
#Override
public void onAttach(Activity activity)
{
super.onAttach(activity);
mCallback = (TaskCallback) activity;
}
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setRetainInstance(true);
mTask = new Task();
mTask.execute();
}
private class Task extends AsyncTask<Void, Integer, Void>
{
#Override
protected void onPreExecute()
{
mCallback.onPreExecute();
}
#Override
protected Void doInBackground(Void... params)
{
for (int i=0; i<100; i++)
{
publishProgress(i*10);
}
return null;
}
#Override
protected void onProgressUpdate(Integer... values)
{
mCallback.onProgressUpdate(values);
}
#Override
protected void onPostExecute(Void aVoid)
{
mCallback.onPostExecute();
}
}
}
2) my Main Activity code
public class MainActivity extends ActionBarActivity implements MyFragment.TaskCallback
{
private ProgressBar mProgress;
private MyFragment mTaskFragment;
private final static String TAG_FRAGMENT = "Fragment Task";
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mProgress = (ProgressBar) findViewById(R.id.progressBar1);
mProgress.setProgress(0);
//create fragment manager and fragment instance
FragmentManager mFM = getSupportFragmentManager();
mTaskFragment = (MyFragment) mFM.findFragmentByTag(TAG_FRAGMENT);
if(mFM == null)
{
mTaskFragment = new MyFragment();
mFM.beginTransaction().add(mTaskFragment, TAG_FRAGMENT).commit();
}
//I added this method, but to no help, the same without this method
mFM.executePendingTransactions();
}
#Override
public void onPreExecute()
{
mProgress.setVisibility(View.VISIBLE);
}
#Override
public void onProgressUpdate(Integer... i)
{
mProgress.setProgress(i[0]);
}
#Override
public void onPostExecute()
{
mProgress.setVisibility(View.INVISIBLE);
}
}
Basically, when run the code by Debug, after
mTaskFragment = (MyFragment) mFM.findFragmentByTag(TAG_FRAGMENT);
if(mFM == null)
{
mTaskFragment = new MyFragment();
mFM.beginTransaction().add(mTaskFragment, TAG_FRAGMENT).commit();
}
Gives mTaskFragment = null
I suppose here is the problem (mTaskFragment = null), the code doesn't create instance of MyFragment.
The question: how should I change the code to update ProgressBar from background by using this (Fragment + AsyncTask) pattern?
another question: Fragment onAttached(Activity a) is deprecated, now we should use onAttached(Context context), does it mean it should be implemented like: mCallback = (TaskCallback) context;?
Replace if(mFM == null) with if(mTaskFragment == null) you want to check if the fragment is null not the FragmentManager.
Also the updated method for:
public void onAttach(Activity activity) is public void onAttach(Context context)
Using: mCallback = (TaskCallback) context; is fine as Context is a superclass of Activty (just make sure your Activity is implementing the interface)

Comunicattion between fragments

I'm creating an app, and I have a doubt on how to communicate between fragments, I know I must communicate to the parent activity and etcetera my question is more best practice oriented. My app consists of a MainActivity with a navigation drawer which depending on the selection calls a fragment and puts it on the main screen.
I have 2 fragments which via a button need to call another fragment (I can convert it to an activity with no problem) that opens the camera to scan a barcode (BarScanFragment) (https://github.com/dm77/barcodescanner).
My question is it possible to know which fragment called the BarScanFragment so I can send the argument to the correct fragment, and how do I achieve it.
BarScanFragment.java
public class BarScanFragment extends Fragment implements ZXingScannerView.ResultHandler{
private ZXingScannerView mScannerView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mScannerView = new ZXingScannerView(getActivity());
return mScannerView;
}
#Override
public void onResume() {
super.onResume();
mScannerView.setResultHandler(this);
mScannerView.startCamera();
}
#Override
public void onPause() {
super.onPause();
mScannerView.stopCamera();
}
#Override
public void handleResult(Result result) {
Log.i("TAG", result.getText());
Bundle args = new Bundle();
args.putString("barcodeScan", result.getText());
}
FragmentA.java
......
......
barcodeButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Fragment content = new BarScanFragment();
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.flFragmentContainer, content).addToBackStack("TRADEIN")
.commit();
/*Intent intent = new Intent(rootView.getContext(), BarcodeScannerActivity.class);
startActivity(intent);*/
}
});
Fragment b.java
.....
.....
barcodeButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Fragment content = new BarScanFragment();
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.flFragmentContainer, content).addToBackStack("INFOPRODUCT")
.commit();
/*Intent intent = new Intent(rootView.getContext(), BarcodeScannerActivity.class);
startActivity(intent);*/
}
});
Take a look on setTargetFragment and getTargetFragment. It's the easiest way to communicate back and forth between fragment.
Here there is a little example https://github.com/alexfu/TargetFragmentExample
You can add a parameter to the BarScanFragment's constructor:
public BarScanFragment(int creatorFragment) {
// Do something with creatorFragment
}
Save "creatorFragment" values in your activity:
public static final int FRAGMENT_1 = 0;
public static final int FRAGMENT_2 = 1;
Then in your button listeners create the BarScanFragment with a specific value:
Fragment content = new BarScanFragment(MainActivity.FRAGMENT_1);
or
Fragment content = new BarScanFragment(MainActivity.FRAGMENT_2);
Declare callbacks in your activity and call methods from another fragment using these callbacks
public interface Callback1 {
void callbackMethod1();
}
public interface Callback2 {
void callbackMethod2();
}
public class Activity extends ActionBarActivity implements Callback1, Callback2 {
Fragment1 mFragment1;
Fragment2 mFragment2;
#Override
public void callbackMethod1() {
mFragment2.method2();
}
#Override
public void callbackMethod2() {
mFragment1.method1();
}
}
public class Fragment1 extends Fragment {
Callback1 callback;
#Override
public void onAttach(android.app.Activity activity) {
super.onAttach(activity);
callback = (Callback1) getActivity();
}
void callMethodOfFragment1() {
callback.callbackMethod1();
}
#Override
public void onDetach() {
super.onDetach();
callback = null;
}
public void method1() {
do_sth_in_fr2();
}
}
public class Fragment2 extends Fragment {
Callback2 callback;
#Override
public void onAttach(android.app.Activity activity) {
super.onAttach(activity);
callback = (Callback2) getActivity();
}
void callMethodOfFragment2() {
callback.callbackMethod2();
}
#Override
public void onDetach() {
super.onDetach();
callback = null;
}
public void method2() {
do_sth_in_fr1();
}
}

Android AsyncLoader: Share objects between fragmentactivity/fragment

I have a problem regarding with FragmentActivity and mutltiple Fragments inside a ViewPager.
In the FragmentActivity an object is loaded, with a AsyncTask which is used in all the other fragments. I have used the android:configChanges="orientation|keyboardHidden|keyboard" "hack" to make sure the object is only loaded once, even during a screen rotation.
However, now I would to like to display more infromation in landscape modus in one of the Fragments, so now that hack doesn't work.
I've tried implementing a AsyncLoader and the FragmentRetainInstanceSupport from the Android samples. But none of the things work:
1 - I can't get the FragmentRetainInstanceSupport get to work within the ViewPager, when I follow the sample code the onCreate() method isn't called in the worker-fragment
2 - The AsyncLoader crashes during a screen rotation...
Here is my code in which I (tried to) implement the AsyncLoader:
public class TeamActivity extends SherlockFragmentActivity implements LoaderManager.LoaderCallbacks<Response<Team>> {
ViewPager mPager;
PageIndicator mIndicator;
FragmentPagerAdapter mAdapter;
private final int MENU_FOLLOW = Menu.FIRST;
private final int MENU_UNFOLLOW = Menu.FIRST + 1;
Team team = null;
static int team_id;
public Team getTeam(){
return team;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
team_id = this.getIntent().getIntExtra("index", 0);
Log.d("Teamid",""+team_id);
getSupportLoaderManager().initLoader(0, null, this);//.forceLoad();
//getSupportLoaderManager().getLoader(0).startLoading();
//new getTeam().execute();
}
#Override
public boolean onPrepareOptionsMenu(Menu menu) {
if(team != null) {
team.getNaam();
SharedPreferences keyValues = this.getSharedPreferences("teams_follow", Context.MODE_PRIVATE);
MenuItem menuItem_volg = menu.findItem(MENU_FOLLOW);
MenuItem menuItem_delete = menu.findItem(MENU_UNFOLLOW);
if(keyValues.contains(String.valueOf(team.getStartnummer()))) {
menuItem_volg.setVisible(false);
menuItem_delete.setVisible(true);
} else {
menuItem_volg.setVisible(true);
menuItem_delete.setVisible(false);
}
}
return super.onPrepareOptionsMenu(menu);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0,MENU_UNFOLLOW,Menu.NONE, R.string.ab_verwijderen)
.setIcon(R.drawable.ic_action_delete)
.setVisible(false)
.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
menu.add(0,MENU_FOLLOW,Menu.NONE, R.string.ab_volgen)
.setIcon(R.drawable.ic_action_star)
.setVisible(false)
.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
Utils.goHome(getApplicationContext());
break;
case MENU_FOLLOW:
Utils.addFavoTeam(getApplicationContext(), team);
invalidateOptionsMenu();
break;
case MENU_UNFOLLOW:
Utils.removeFavoteam(getApplicationContext(), team.getID());
invalidateOptionsMenu();
break;
}
return super.onOptionsItemSelected(item);
}
class TeamFragmentAdapter extends FragmentPagerAdapter implements TitleProvider {
ArrayList<Fragment> fragments = new ArrayList<Fragment>();
ArrayList<String> titels = new ArrayList<String>();
public TeamFragmentAdapter(FragmentManager fm) {
super(fm);
fragments.add(new TeamInformatieFragment());
titels.add("Informatie");
fragments.add(new TeamLooptijdenFragment());
titels.add("Routetijden");
}
#Override
public Fragment getItem(int position) {
return fragments.get(position);
}
#Override
public int getCount() {
return fragments.size();
}
#Override
public String getTitle(int position) {
return titels.get(position);
}
}
private class getTeam extends AsyncTask<Void, Void, Void> {
private ProgressDialog progressDialog;
Response<Team> response;
protected void onPreExecute() {
progressDialog = ProgressDialog.show(TeamActivity.this,
"Bezig met laden", "Team wordt opgehaald...", true);
progressDialog.setCancelable(true);
progressDialog.setOnCancelListener(new OnCancelListener() {
public void onCancel(DialogInterface dialog) {
cancel(true);
Utils.goHome(TeamActivity.this);
}
});
}
#Override
protected Void doInBackground(Void... arg0) {
if(!isCancelled())
response = api.getTeamByID(team_id);
return null;
}
#Override
protected void onPostExecute(Void result) {
if(Utils.checkResponse(TeamActivity.this, response)) {
setContentView(R.layout.simple_tabs);
team = response.getResponse();
mAdapter = new TeamFragmentAdapter(getSupportFragmentManager());
mPager = (ViewPager)findViewById(R.id.pager);
mPager.setAdapter(mAdapter);
mIndicator = (TabPageIndicator)findViewById(R.id.indicator);
mIndicator.setViewPager(mPager);
invalidateOptionsMenu();
progressDialog.dismiss();
}
}
}
public static class AppListLoader extends AsyncTaskLoader<Response<Team>> {
Response<Team> response;
public AppListLoader(Context context) {
super(context);
}
#Override public Response<Team> loadInBackground() {
response = api.getTeamByID(team_id);
return response;
}
#Override public void deliverResult(Response<Team> response) {
if (isReset()) {
return;
}
this.response = response;
super.deliverResult(response);
}
#Override protected void onStartLoading() {
if (response != null) {
deliverResult(response);
}
if (takeContentChanged() || response == null) {
forceLoad();
}
}
#Override
protected void onStopLoading() {
// Attempt to cancel the current load task if possible.
cancelLoad();
}
#Override
protected void onReset() {
super.onReset();
// Ensure the loader is stopped
onStopLoading();
response = null;
}
}
private ProgressDialog progressDialog;
#Override
public Loader<Response<Team>> onCreateLoader(int arg0, Bundle arg1) {
progressDialog = ProgressDialog.show(TeamActivity.this,
"Bezig met laden", "Team wordt opgehaald...", true);
progressDialog.setCancelable(true);
progressDialog.setOnCancelListener(new OnCancelListener() {
public void onCancel(DialogInterface dialog) {
finish();
}
});
return new AppListLoader(this);
}
#Override
public void onLoadFinished(Loader<Response<Team>> loader, Response<Team> response) {
//Log.d("Loader", "Klaar");
if(Utils.checkResponse(TeamActivity.this, response)) {
team = response.getResponse();
setContentView(R.layout.simple_tabs);
mAdapter = new TeamFragmentAdapter(getSupportFragmentManager());
mPager = (ViewPager)findViewById(R.id.pager);
mPager.setAdapter(mAdapter);
mIndicator = (TabPageIndicator)findViewById(R.id.indicator);
mIndicator.setViewPager(mPager);
invalidateOptionsMenu();
progressDialog.dismiss();
}
}
#Override
public void onLoaderReset(Loader<Response<Team>> arg0) {
//Utils.goHome(this);
}
}
Fragment (example):
public class TeamInformatieFragment extends SherlockFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Team team = ((TeamActivity)this.getActivity()).getTeam();
//ERROR ON NEXT LINE AFTER SCREEN ROTATION:
getSherlockActivity().getSupportActionBar().setTitle(team.getNaam());
View view = inflater.inflate(R.layout.team_informatie, container, false);
return view;
}
}
The method is called from the fragments (with getActivity().getTeam()) but after a screen rotation getTeam() returns null;
I think the fragments are calling getTeam() too fast, before the variable team has been initialized(?)
Can you please help me?
Thank you!
This is probably not what you want to hear, but I recommend getting rid of
android:configChanges="orientation|keyboardHidden|keyboard"
It's an ugly hack, and a lot of the newer SDK elements like Loaders will break if you don't handle configuration changes correctly. Let Android handle the config changes, and design your code around that.

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