I have an Weather adapter to show the weather, the activity is split into two screens, one half a listview (different adapter), the other is tablayout with another tablayout inside to scroll through all the different pages of weather that are available
After turning off the wifi to make sure i don't receive anything and then turning on the wifi to receive the weather i get the update method called for the adapter and the list is updated, new fragments created, onViewCreated is called but the fragments display as blank and as only 1 (can't cycle through them if there are multiple).
Here is the Weather ViewPagerAdapter
public class WeatherViewPagerAdapter extends FragmentStatePagerAdapter {
private List<Fragment> fragments;
public WeatherViewPagerAdapter(FragmentManager fm) {
super(fm);
fragments = new LinkedList<>();
if (Storage.getInstance().getWeatherModels().size() == 0){
// Displays page but with "no weather available" message
fragments.add(WeatherFragment.newInstance(null));
}else{
for (CurrentWeatherModel model : Storage.getInstance().getWeatherModels()){
fragments.add(WeatherFragment.newInstance(model));
}
}
}
public void rediscoverWeather(){
fragments.clear();
if (Storage.getInstance().getWeatherModels().size() == 0){
fragments.add(WeatherFragment.newInstance(null));
}else{
for (CurrentWeatherModel model : Storage.getInstance().getWeatherModels()){
fragments.add(WeatherFragment.newInstance(model));
}
}
}
#Override
public int getItemPosition(#NonNull Object object) {
return POSITION_NONE;
}
#Override
public int getCount() {
return fragments.size();
}
#Override
public Fragment getItem(int position) {
return fragments.get(position);
}
#Override
public Parcelable saveState() {
return null;
}
}
And this is the fragment that is in the Tablayout on the side that displays the weather
public class WeatherViewPagerFragment extends Fragment {
private WeatherViewPagerAdapter adapter;
private ViewPager viewpager;
private TabLayout tabLayout;
public static WeatherViewPagerFragment newInstance(){
return new WeatherViewPagerFragment();
}
#Override
public UniqueInfo getUniqueInfo() {
return null;
}
#Override
public void update() {
adapter.rediscoverWeather();
setPage(0);
adapter.notifyDataSetChanged();
}
public void setPage(int pageNumber){
if (pageNumber >=0 && pageNumber < adapter.getCount()){
viewpager.setCurrentItem(pageNumber, true);
}
}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.weather_view_pager, container, false);
}
private void createAdapter(){
adapter = new WeatherViewPagerAdapter(getChildFragmentManager());
viewpager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewpager);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
viewpager = view.findViewById(R.id.viewpager);
tabLayout = view.findViewById(R.id.sliding_tabs);
createAdapter();
}
}
The update() for WeatherViewPagerFragment gets called when its meant to, which updates the Adapter, re-doing the fragments and calling onCreateView and onViewCreated, but what i see is just a blank fragment, any suggestions why this would be happening? i figured it could be a focus issue but i haven't had any luck as of yet with fixing it
Related
Sorry for my english. I have one activity and in this activity in FragmentPagerAdapter exist 5 fragments. All fragments use one object model for inforation(product name, product image ...).
My activity get data from data base. And then it data send to all fragments. My example Activity:
#BindView(R.id.tabs_sep_prod) TabLayout tabs_sep_prod;
#BindView(R.id.viewpager_sep_prod) ViewPager viewpager_sep_prod;
PrepBaseProdFragment prepBaseProdFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sep_product);
ButterKnife.bind(this);
prepBaseProdFragment = new PrepBaseProdFragment();
// there i have another fragments
// ...
setupViewPager(viewpager_sep_prod);
tabs_sep_prod.setupWithViewPager(viewpager_sep_prod);
}
private void setupViewPager(ViewPager viewPager) {
SepProductActivity.ViewPagerAdapter adapter = new SepProductActivity.ViewPagerAdapter(
adapter.addFrag(prepBaseProdFragment, getString(R.string.sep_prep_base));
// there i have another addFrag
// ...
viewPager.setOffscreenPageLimit(5);
viewPager.setAdapter(adapter);
}
#Override
public void onResume() {
super.onResume();
// this i call method from presenter, it return data in method setData
if(idCat != null && idProd != null)
sepProductPresenter.getSepProd(idCat, idProd);
}
#Override
public void setData(SepProductModel sepProductModel) {
// there i send data to fragment
prepBaseProdFragment.setDataInf(sepProductModel);
// ...
}
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 addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
my fragment
public class PrepBaseProdFragment extends BaseFragment {
#BindView(R.id.text) TextView text;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_about_prod_prepare_base, parent, false);
ButterKnife.bind(this, view);
Log.e("PrepBaseProdFragment", "PrepBaseProdFragment");
return view;
}
public void setDataInf(SepProductModel sepProductModel) {
text.setText(sepProductModel.getPROPERTY_PR_SUBSTRPREP_UA_VALUE().getTEXT());
}
}
My question: when i send data from activity to fragment, my view do not have time to initialize. In fragment line text.setText(sepProductModel.getPROPERTY_PR_SUBSTRPREP_UA_VALUE().getTEXT()); error
java.lang.NullPointerException: Attempt to invoke virtual method 'void
android.widget.TextView.setText(java.lang.CharSequence)' on a null
object reference
Please, help me solve my problem. I spend many times for this
You can check if the text view is null save the data in a variable inside the fragment and in onCreateView use the data variable if it is filled and set the textview text.
Something like this:
// Inside the Fragment body
private SepProductModel sepProductModel;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_about_prod_prepare_base, parent, false);
ButterKnife.bind(this, view);
Log.e("PrepBaseProdFragment", "PrepBaseProdFragment");
if(this.sepProductModel != null)
text.setText(this.sepProductModel.getPROPERTY_PR_SUBSTRPREP_UA_VALUE().getTEXT());
return view;
}
public void setDataInf(SepProductModel sepProductModel) {
if(text != null){
// use text
}
else this.sepProductModel=sepProductModel;
}
I can advise you to wait for your data and then show fragments to adapter, moreover all of them use the same model. While you dont have data, you can show progress bar.
When you have needed model, you can create instances of your fragments and set bundle arguments for them. You can use method like this:
public static MyFragment newInstance(MyModel model){
MyFragment fragment = new MyFragment();
Bundle args = new Bundle();
args.putSerializable(KEY, model);//or args.putParcelable(KEY, model);
fragment.setArguments(args);
return fragment;
}
Notice: your model need to implement Serializable or Parcelable to be putted in bundle. You may read about difference here.
Then in your set data method, when you already have your model you can setup your adapter and set it to view pager, but with this approach:
adapter.addFrag(MyFragment.newInstance(model), getString(R.string.sep_prep_base));
It have to help you, ask me if you have some questions.
I have googled everything during a day about the subject and nothing seems to work around for my project. I have added a viewpager to my main activity. There is two fragments attached to it thanks to a page adapter. I initialized everything on the OnCreate method from my main activity. The view pager work well. The problem is when I want to access from my MainActivity the textviews included in my fragments. I created a Set method in each fragment which modify the textviews accordingly to the arguments. So in order to call this method from my MainActivity I have to instantiate the fragments on my MainActivity and the problem is that this line of code return null and the fragments can not be instantiated. Here is the code used for testing this purpose.
Main Activity
public class MainActivity extends AppCompatActivity{
private SecondActivitySwipeAdapter adapterViewPager;
private FirstFragmentSwipe fragment1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.v(TAG, "onCreate");
setContentView(R.layout.main_activity_test);
ViewPager vpPager = (ViewPager) findViewById(R.id.viewpager);
adapterViewPager = new SecondActivitySwipeAdapter(getSupportFragmentManager());
vpPager.setAdapter(adapterViewPager);
fragment1 = (FirstFragmentSwipe) adapterViewPager.getRegisteredFragment(vpPager.getCurrentItem());
fragment1.setTextViews(1,2,3,4,5);
}
...
}
SecondActivitySwipeAdapter
public class SecondActivitySwipeAdapter extends FragmentStatePagerAdapter {
SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
private static int NUM_ITEMS = 2;
private FragmentManager mFragmentManager;
public SecondActivitySwipeAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
mFragmentManager = fragmentManager;
}
// Returns total number of pages
#Override
public int getCount() {
return NUM_ITEMS;
}
// Returns the fragment to display for that page
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return FirstFragmentSwipe.newInstance();
case 1:
return SecondFragmentSwipe.newInstance();
default:
return null;
}
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
}
FirstFragmentSwipe
public class FirstFragmentSwipe extends Fragment {
private TextView avg1;
private TextView avg2;
private TextView avg3;
private TextView avg4;
private TextView avg5;
public static FirstFragmentSwipe newInstance(){
return new FirstFragmentSwipe();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.swipelayout1, container, false);
avg1 = view.findViewById(R.id.pwrAvgNmbview1);
avg2 = view.findViewById(R.id.pwrAvgNmbview2);
avg3 = view.findViewById(R.id.pwrAvgNmbview3);
avg4 = view.findViewById(R.id.pwrAvgNmbview4);
avg5 = view.findViewById(R.id.pwrAvgNmbview5);
return view;
}
public void setTextViews(int avg1, int avg2, int avg3, int avg4, int avg5){
this.avg1.setText(Integer.toString(avg1));
this.avg2.setText(Integer.toString(avg2));
this.avg3.setText(Integer.toString(avg3));
this.avg4.setText(Integer.toString(avg4));
this.avg5.setText(Integer.toString(avg5));
}
}
The second fragment is basically the same as fragment for the moment. I am using some ideas found by googling. The last line of the onCreate method make the app crash. Thanks for you precious help.
So the problem here is that registeredFragments doesn't have the fragments instantiated yet.
First you can check if fragment1 is null to prevent crashes.
Furthermore you'd rather put initialization methods in getItem() of adapter or in onViewCreated() of the fragment and do some updates in later lifecycle methods if needed.
I have got classic Bottom Navigation created by default with 3 TABs (FragmentOne, FragmentTwo and FragmentThree).
The first fragment (FragmentOne) has ViewPager with two static inner Fragments (FragmentInner1 and FragmentInner2).
When app starts evrything is fine so at the FragmentOne we can see FragmentInner1 and can navigate to FragmentInner2.
But after navigating from FragmentTwo to FragmentOne the FragmentInner1 is not visible. That is a problem.
I guess we should recreate it somehow?
I investigated manual from here https://developer.android.com/guide/components/fragments.html and https://developer.android.com/training/implementing-navigation/lateral.html#PagerTitleStrip but it does not help and my code looks the same way.
Please help. Thank you!
FragmentOne
public class FragmentOne extends Fragment {
//This is our viewPager
private ViewPager viewPager;
//Fragments
FragmentInner1 fragmentInner1;
FragmentInner2 fragmentInner2;
ViewPagerAdapter adapter;
private View view;
public FragmentOne() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_fragment_one, container, false);
//Initializing viewPager
viewPager = (ViewPager) view.findViewById(R.id.viewpager);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
setupViewPager(viewPager);
return view;
}
private void setupViewPager(ViewPager viewPager) {
adapter = new ViewPagerAdapter(getActivity().getSupportFragmentManager());
fragmentInner1=new FragmentInner1();
fragmentInner2=new FragmentInner2();
adapter.addFragment(fragmentInner1);
adapter.addFragment(fragmentInner2);
viewPager.setAdapter(adapter);
}
#Override
public void onAttach(Context context)
{
super.onAttach(context);
}
#Override
public void onResume() {
super.onResume();
}
#Override
public void onPause() {
super.onPause();
}
#Override
public void onDestroy() {
super.onDestroy();
}
}
ViewPagerAdapter
public class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
Fragment fragment = mFragmentList.get(position);
return fragment;
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment) {
mFragmentList.add(fragment);
}
}
FragmentInner1
public class FragmentInner1 extends Fragment {
public static FragmentInner1 newInstance( ) {
FragmentInner1 fragment = new FragmentInner1();
return fragment;
}
public FragmentInner1() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_fragment_inner1, container, false);
}
}
You have to Use getChildFragmentManager() For Viewpager to adapt Popback Feature.
adapter = new ViewPagerAdapter(getChildFragmentManager());
This is Because the Viewpager have multiple Fragments where Viewpager itself or is holded by another Fragment. So the Child Fragment is to Be Invoked and Used.
You Can Refer this Documentation on ChildFragmentManager()
i'm facing an issue i can't seem to resolve and i'd like some help.
My app is composed by an activity containing a fragment. After the user taps on a suggestion, activity's method onSuggestionClicked(String cardId) is called and activity's content is replaced with a new PagerFragment_new.
#Override
public void onSuggestionClicked(String cardId) {
Log.d("activity","ID:\t" + cardId);
PagerFragment_new pagerFragment = PagerFragment_new.getInstance(
Injection.provideMtgDatabase(getApplicationContext()),
activityPresenter.getAllCardExpansionIds(cardId),
this);
ActivityUtils.replaceFragment(getSupportFragmentManager(), pagerFragment, R.id.MTGRecallActivity_container);
}
PagerFragment_new contains a ViewPager to display CardInfoFragment_new
public class PagerFragment_new extends MtgRecallFragment_new implements PagerFragmentContract.View {
private View fragmentView;
private ViewPager viewPager;
private PagerFragmentContract.Presenter presenter;
private ScreenSlidePageAdapter_new adapter;
private MtgDatabase database;
private String[] printingsIds;
private ScreenSlidePageAdapter_new.ActivePresenterListener listener;
public PagerFragment_new() {
//Required empty constructor
}
public static PagerFragment_new getInstance(MtgDatabase database, String[] printingsIds, ScreenSlidePageAdapter_new.ActivePresenterListener listener) {
PagerFragment_new instance = new PagerFragment_new();
instance.setDatabase(database);
instance.setPrintingsIds(printingsIds);
instance.listener = listener;
return instance;
}
//other stuff
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
setRetainInstance(true);
super.onCreate(savedInstanceState);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
setHasOptionsMenu(true);
fragmentView = inflater.inflate(R.layout.fragment_pager, container, false);
viewPager = (ViewPager) fragmentView.findViewById(R.id.PAGERFRAG_VIEWPAGER);
adapter = new ScreenSlidePageAdapter_new(getChildFragmentManager(), printingsIds, database, viewPager);
adapter.setListener(listener);
viewPager.setAdapter(adapter);
viewPager.setOffscreenPageLimit(1);
return fragmentView;
}
#Override
public void setPresenter(PagerFragmentContract.Presenter presenter) {
this.presenter = presenter;
}
}
The adapter to manage ViewPager's element's is ScreenSlidePageAdapter_new, it is responsible of instantiating CardInfoFragments.
public class ScreenSlidePageAdapter_new extends FragmentStatePagerAdapter {
private String[] printingsIds;
private String firstItemId;
private MtgDatabase database;
public ActivePresenterListener activity;
private ViewPager viewPager;
public ScreenSlidePageAdapter_new(FragmentManager fm, String[] printingsIds, MtgDatabase database, ViewPager viewPager) {
super(fm);
this.printingsIds =printingsIds;
this.database = database;
this.firstItemId = printingsIds[0];
this.viewPager = viewPager;
}
#Override
public Fragment getItem(int position) {
//todo create a bundle with cardId
Bundle bundle = new Bundle();
bundle.putString("CardID", printingsIds[position]);
bundle.putString("FirstItemId", firstItemId);
CardInfoFragment_new cardInfoFragment_new = CardInfoFragment_new.getInstance(viewPager);
cardInfoFragment_new.setArguments(bundle);
CardInfoPresenter cardInfoPresenter = new CardInfoPresenter(cardInfoFragment_new, database);
activity.setActivePresenter(cardInfoPresenter);
return cardInfoFragment_new;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
super.destroyItem(container, position, object);
}
public void setListener(ActivePresenterListener listener) {
this.activity = listener;
}
#Override
public int getCount() {
return printingsIds.length;
}
public interface ActivePresenterListener {
void setActivePresenter(BasePresenter presenter);
}}
Finally, here's the code of CardInfoFragment:
public class CardInfoFragment_new extends MtgRecallFragment_new
implements CardInfoContract.View,
CardPrintingsAdapter.OnItemClickListener {
private ViewPager viewPager;
public CardInfoContract.Presenter presenter;
private View fragmentView;
private MTGCard mtgCard;
RecyclerView printingsRecyclerView;
CardPrintingsAdapter cardPrintingsAdapter;
private String firstItemId; //the first id
public CardInfoFragment_new() {
//required empty constructor
}
private void setViewPager(ViewPager viewPager) {
this.viewPager = viewPager;
}
public static CardInfoFragment_new getInstance(ViewPager viewPager) {
CardInfoFragment_new cardInfoFragment_new = new CardInfoFragment_new();
cardInfoFragment_new.setViewPager(viewPager);
return cardInfoFragment_new;
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
setRetainInstance(true);
presenter.start();
String cardId = getArguments().getString("CardID");
firstItemId = getArguments().getString("FirstItemId");
mtgCard = presenter.getCardData(cardId);
super.onCreate(savedInstanceState);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
fragmentView = inflater.inflate(R.layout.fragment_card_info_new, container, false);
setUpCardInfoView(fragmentView);
return fragmentView;
}
public void setUpCardInfoView(final View view){
//others view set-up action omitted
cardprintingsContainer = (LinearLayout) view.findViewById(R.id.CARDINFO_printingsContainer);
printingsRecyclerView = (RecyclerView)fragmentView.findViewById(R.id.CARDINFO_printings_recyclerView);
final List<String> printings = presenter.getCardPrintings(firstItemId, mtgCard.getName());
if (printings.size() < 40) {
setupPrintings(printings,printingsRecyclerView);
}
else {
LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout printingsRow = new LinearLayout(getContext());
printingsRow = (LinearLayout)inflater.inflate(R.layout.card_info_printings_row,printingsRow,true);
printingsRow.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
setupPrintings(printings, printingsRecyclerView);
}
});
ImageView printingssetImage = (ImageView)printingsRow.findViewById(R.id.CARDINFO_printingsRow_setImage);
printingssetImage.setVisibility(View.INVISIBLE);
TextView printingssetName = (TextView)printingsRow.findViewById(R.id.CARDINFO_printingsRow_setName);
printingssetName.setText("Click to see all the "+printings.size()+ " versions");
cardprintingsContainer.addView(printingsRow);
}
}
public void setupPrintings(List<String> printings, RecyclerView recyclerView) {
cardPrintingsAdapter =
new CardPrintingsAdapter(getContext(), printings);
cardPrintingsAdapter.setOnItemClickListener(this);
UnscrollableLayoutManager layoutManager = new UnscrollableLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false);
recyclerView.setAdapter(cardPrintingsAdapter);
recyclerView.setLayoutManager(layoutManager);
}
#Override
public void onItemClick(View itemView, int position) {
int i = viewPager.getAdapter().getCount();
viewPager.setCurrentItem(position);
}
#Override
public void onDestroy() {
presenter = null;
mtgCard = null;
super.onDestroy();
}}
When user click on a RecyclerView item, CardInfoFragment's method onItemClick(View itemView, int position) is called and the viewpager is set to current position. Everything as expected.
THE PROBLEM
When the orientation changes, fragments are able to retain their states, but viewPager.setCurrentItem(position) does nothing, and i'm not able to change displayed fragment.
I already checked:
ViewPager instance and adapters instances corresponds to those passed to Fragments
onItemClick is fired
this questions question1 question2
If i use
android:configChanges="orientation|screenSize"
in manifest it works even after config changes, but i don't want to use this option since is discouraged.
Thanks in advance!
By default, when certain key configuration changes happen on Android (a common example is an orientation change), Android fully restarts the running Activity to help it adjust to such changes.
When you define android:configChanges="keyboardHidden|orientation" in your AndroidManifest, you are telling Android: "Please don't do the default reset when the keyboard is pulled out, or the phone is rotated; I want to handle this myself. Yes, I know what I'm doing".
So use configChanges.
The use of this is discouraged, IF you don't know how to use it. But for a case like this, I would suggest you use it. IF not, still the activity will be recreated. which just takes time, resources, and I don't see why you would want that to happen.
Friends, I've spent enough time to find an answer to my question(here and on android's site) But no luck.
Here is the logic:
From DialogFragment upon finishing putting user's data he clicks OK button:
import de.greenrobot.event.EventBus;
...
public class AddDialogFragment extends DialogFragment implements
DialogInterface.OnClickListener {
...
public void onClick(DialogInterface dialog, int which) {
StringBuilder date = new StringBuilder(today.getText().subSequence(0,
today.getText().length()));
date = (date.toString().equals(getString(R.string.today))) ? new StringBuilder("20150104") : date;
int weight = 89;
String[] bsi = rb.getSelectedItems();
String[] gsi = rg.getSelectedItems();
DatabaseManipulation dm = new DatabaseManipulation(getActivity());
dm.run(date, weight, bsi, gsi);
dm.destroy();
DialogDataModel toSend = new DialogDataModel(weight, date.toString(), bsi, gsi);
/*
Context activity = getActivity();
if (activity instanceof WDActivity)
((WDActivity) activity).updateListItemFragment();
*/
EventBus.getDefault().post(new UpdateItemEvent(toSend));
Log.d(LOG_TAG, "send event");
Toast.makeText(getActivity(), R.string.saved_data, Toast.LENGTH_LONG).show();
}
...
Event is successfully sent to Adapter class which is registered for receiving this event:
...
import de.greenrobot.event.EventBus;
public class ItemsAdapter extends BaseAdapter implements ListAdapter {
private static final String LOG_TAG = "Logs";
private ArrayList<DialogDataModel> list = new ArrayList<DialogDataModel>();
private Context activity;
public ItemsAdapter (ArrayList<DialogDataModel> list, Context context) {
this.list = list;
this.activity = context;
registerEventBus();
}
#Override
public int getCount() {
return list.size();
}
#Override
public Object getItem(int pos) {
return list.get(pos);
}
#Override
public long getItemId(int pos) {
return pos;
//just return 0 if your list items do not have an Id variable.
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
LayoutInflater inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.row_item, null);
}
DialogDataModel curData = list.get(position);
TextView itemDate = (TextView)view.findViewById(R.id.item_date);
itemDate.setText(curData.getDate());
TextView itemWeight = (TextView)view.findViewById(R.id.item_weight);
itemWeight.setText( Integer.toString(curData.getWeight()) );
TextView itemEvents = (TextView)view.findViewById(R.id.item_events);
itemEvents.setText(curData.getEventsShort());
//Handle buttons and add onClickListeners
ImageButton editBtn = (ImageButton)view.findViewById(R.id.item_edit_btn);
editBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (activity instanceof WDActivity)
((WDActivity) activity).AddNewData(v, list.get(position));
notifyDataSetChanged();
}
});
ImageButton deleteBtn = (ImageButton) view.findViewById(R.id.item_delete_btn);
deleteBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String date = list.get(position).getDate();
DatabaseManipulation dm = new DatabaseManipulation(activity);
dm.deleteItem(date);
dm.destroy();
list.remove(position);
notifyDataSetChanged();
}
});
return view;
}
public void registerEventBus(){
if (!EventBus.getDefault().isRegistered(this)) EventBus.getDefault().register(this);
Log.d(LOG_TAG, "Registred from adapter");
}
public void unregisterEventBus(){
EventBus.getDefault().unregister(this);
}
public void onEventMainThread(UpdateItemEvent event) {
Log.d(LOG_TAG, "Event fired!");
list = DialogDataModel.replaceFieldsInArray(list,event.getModel());
notifyDataSetChanged();
}
}
After clicking OK in dialog window the user sees the list of items and the item he's updated is up to date. Without this logic he sees the old version of this item item in the list and to refresh the list he needs to relaunch the app.
Yes, it's working with EventBus.
But as you can see here in the class there is no place for unregistering it from listening for UpdateItemEvent. Since there are no destructors in java(I don't believe that garbage collector should do this for me) I should handle this. Moreover the class registeres as listener in constructor (it happens several times, that's why you see this ugly if statement(if (!EventBus.getDefault().isRegistered(this))) You may ask me why not getting this adapter through Activity (there is the only one in the app) I tried building a chain AddDialogFragment -> WDActivity -> PlaceholderFragment -> ItemsAdapter
//AddDialogFragment
Context activity = getActivity();
if (activity instanceof WDActivity)
((WDActivity) activity).updateListItemFragment();
//WDActivity --beginTransaction().replace does not work here
...
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_wd);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
}
...
public void updateListItemFragment() {
android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.Fragment currentFragment = fragmentManager.findFragmentById(R.id.container);
if (currentFragment instanceof PlaceholderFragment && currentFragment != null) {
fragmentManager.beginTransaction().remove(currentFragment).commit();
fragmentManager.beginTransaction().add(R.id.container, currentFragment).commit();
((PlaceholderFragment)currentFragment).fillList();
}
//PlaceholderFragment
public class PlaceholderFragment extends Fragment {
private static final String LOG_TAG = "Logs";
private static final String ARG_SECTION_NUMBER = "section_number";
private ListView listViewItem;
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if(getArguments().getInt(ARG_SECTION_NUMBER)==1)
return onCreateViewInputChart(inflater, container, savedInstanceState);
if(getArguments().getInt(ARG_SECTION_NUMBER)==2)
return onCreateViewManual(inflater, container, savedInstanceState);
return onCreateViewInputData(inflater, container, savedInstanceState);
}
private View onCreateViewManual(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_howto, container, false);
return rootView;
}
private View onCreateViewInputData(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_list_data, container, false);
findViewsByIdListItem(rootView);
fillList();
return rootView;
}
private View onCreateViewInputChart(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_chart, container, false);
return rootView;
}
//listViewItems
private void findViewsByIdListItem(View v) {
listViewItem = (ListView) v.findViewById(R.id.listViewItems);
}
public void fillList(){
Context activity = getActivity();
DatabaseManipulation dm = new DatabaseManipulation(activity);
ArrayList<DialogDataModel> aldm = dm.getItemsList();
dm.destroy();
ItemsAdapter innerAdapter = new ItemsAdapter(aldm, activity);
listViewItem.setAdapter(innerAdapter);
( (BaseAdapter) listViewItem.getAdapter() ).notifyDataSetChanged();
}
#Override
public void onAttach(Context activity) {
super.onAttach(activity);
}
#Override
public void onDetach(){
super.onDetach();
}
}
//SectionsPagerAdapter - just for your information
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
return PlaceholderFragment.newInstance(position);
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "Enter your data";
case 1:
return "Chart";
case 2:
return "How to use it";
}
return null;
}
}
//ItemsAdapter is placed higher
This did not work. Finally I found out that the bottleneck is in linking PlaceholderFragment and ListAdapter: listViewItem is null everywhere except onCreateViewInputData. I could not figure out why. Google didn't give me the answer and I took it as a magic. Btw due to this feature I cannot use PlaceholderFragment's onAttach and onDetach for saying ItemsAdapter to register/unregister for receiving the event. This:
#Override
public void onAttach(Context activity) {
super.onAttach(activity);
( (ItemsAdapter) listViewItem.getAdapter() ).registerEventBus();
}
doesn't work for the same reason listViewItem is null. Maybe there is some way to manage with this more accurately?
Finally I cope with this: the bottleneck is in linking PlaceholderFragment and ListAdapter: listViewItem is null everywhere except onCreateViewInputData . Below is rewised SectionsPagerAdapter:
public class SectionsPagerAdapter extends FragmentPagerAdapter {
Context activity;
SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
public SectionsPagerAdapter(FragmentManager fm, Context activity) {
super(fm);
this.activity = activity;
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
return PlaceholderFragment.newInstance(position);
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return activity.getString(R.string.chart);
case 1:
return activity.getString(R.string.weight_diary);
case 2:
return activity.getString(R.string.how_to);
}
return null;
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
//maybe use adapater.getRegisteredFragment(viewPager.getCurrentItem());
}
}
and here is my call to the widget in the one of 3 fragments:
public void updateListItemFragment() {
android.support.v4.app.Fragment inputData = mSectionsPagerAdapter.getRegisteredFragment(1);
ListView lv = ((PlaceholderFragment)inputData).listViewItem;
//for test purposes I refill listview with no items - here you need to hand filled BaseAdapter instance: CustomAdapter innerAdapter = new CustomAdapter(ArrayList<yourDataModel>, getContext());
lv.setAdapter(null);
}
And as you've may already wondered there is no need for event bus anymore. Btw if the fragment is not crated yet you need to check it: details are here. Thanks to CommonsWare for quik reply and advice.