Develop Reference

Firebase data display recyclerview in the Tab Layout

I am new to android firebase. The question I have is. The first is to distribute the date from an Activity to several fragments. So far I have solved that problem. But I have a requirement to display the data in Firebase database in each Fragment. But the problem is that the application stops after entering the data in firebase.
stdAttn Activity
public class stdAttnDisplay extends AppCompatActivity {
private ViewPager pager;
private TabLayout tabs;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_std_attn_display);
pager=(ViewPager) findViewById(R.id.vpager);
tabs=(TabLayout) findViewById(R.id.tablayout1);
tabs.setupWithViewPager(pager);
tabs.setTabGravity(TabLayout.GRAVITY_FILL);
tabs.setTabMode(TabLayout.MODE_SCROLLABLE);
setupViewPager(pager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
//bundle
Bundle bundle =new Bundle();
bundle.putString("DATE","01-05-2023");
IABF_Attnfrag frag_iabf = new IABF_Attnfrag();
DABF_Attnfrag frag_dabf = new DABF_Attnfrag();
CMA_Attnfrag frag_cma = new CMA_Attnfrag();
CHARTERED_Attnfrag frag_chartered = new CHARTERED_Attnfrag();
ENGLISH_Attnfrag frag_english = new ENGLISH_Attnfrag();
AAT1_Attnfrag frag_aat1 = new AAT1_Attnfrag();
AAT2_Attnfrag frag_aat2 = new AAT2_Attnfrag();
AAT3_Attnfrag frag_aat3 = new AAT3_Attnfrag();
frag_iabf.setArguments(bundle);
frag_dabf.setArguments(bundle);
frag_cma.setArguments(bundle);
frag_chartered.setArguments(bundle);
frag_english.setArguments(bundle);
frag_aat1.setArguments(bundle);
frag_aat2.setArguments(bundle);
frag_aat3.setArguments(bundle);
adapter.addFrag(frag_iabf,"IABF");
adapter.addFrag(frag_dabf,"DABF");
adapter.addFrag(frag_cma,"CMA");
adapter.addFrag(frag_chartered,"CHARTERED");
adapter.addFrag(frag_english,"ENGLISH");
adapter.addFrag(frag_aat1,"AAT-i");
adapter.addFrag(frag_aat2,"AAT-ii");
adapter.addFrag(frag_aat3,"AAT-iii");
viewPager.setAdapter(adapter);
}
}
Fragment
public class IABF_Attnfrag extends Fragment {
String dateTxt;
private Bundle bundle;
myadapter adapter;
RecyclerView recViewiabf;
private DatabaseReference propertyRef;
public IABF_Attnfrag() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_i_a_b_f__attnfrag, container, false);
recViewiabf = (RecyclerView) view.findViewById(R.id.recViewiabf);
bundle = this.getArguments();
dateTxt = bundle.getString("DATE");
Log.e("DATE_FRAG_INBOUND",""+dateTxt);
propertyRef = FirebaseDatabase.getInstance()
.getReference()
.child("attendance")
.child("IABF")
.child(dateTxt);
propertyRef.keepSynced(true);
recViewiabf.setLayoutManager(new LinearLayoutManager(getContext()));
FirebaseRecyclerOptions<modelAttn> options =
new FirebaseRecyclerOptions.Builder<modelAttn>()
.setQuery(propertyRef, modelAttn.class)
.build();
adapter = new myadapter(options);
recViewiabf.setAdapter(adapter);
return view;
}
#Override
public void onStart() {
super.onStart();
adapter.startListening();
}
#Override
public void onStop() {
super.onStop();
adapter.stopListening();
}
}
Adapter
public class myadapter extends FirebaseRecyclerAdapter<modelAttn,myadapter.myviewholder>
{
public myadapter(#NonNull FirebaseRecyclerOptions<modelAttn> options) {
super(options);
}
#Override
protected void onBindViewHolder(#NonNull myviewholder holder, int position, #NonNull modelAttn model) {
holder.stdFulName.setText(model.getName());
holder.stdidtv.setText(model.getSt_id());
}
#NonNull
#Override
public myviewholder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.attn_item,parent,false);
return new myviewholder(view);
}
public class myviewholder extends RecyclerView.ViewHolder {
TextView stdFulName, stdidtv;
public myviewholder(#NonNull View itemView) {
super(itemView);
stdidtv = itemView.findViewById(R.id.indextext);
stdFulName = itemView.findViewById(R.id.nametext);
}
}
}
Model Attn
public class modelAttn {
String Name, st_id;
public modelAttn() {
}
public modelAttn(String name, String st_id) {
this.Name = name;
this.st_id = st_id;
}
public String getName() {
return Name;
}
public void setName(String name) {
Name = name;
}
public String getSt_id() {
return st_id;
}
public void setSt_id(String st_id) {
this.st_id = st_id;
}
}
FireBase Database Screenshot
Database Screenshot
What I need is to distribute the data from the Activity to the Fragment and then display the relevant data in the RecyclerView using the data in the Firebase database.

If you create a regular adapter then pass it a list of custom objects which you retrieve from firebase. You can make a static list on your MainActivity that can be referenced anywhere including in the fragment.

TabLayoutMediator with ViewPager2 is synchronizing wrong on tab selection -Android java

ViewPager2 is scrolling to the wrong page when I am selecting a tab from a far position. Swiping and selecting tab of loaded pages working fine. The error is only happening when the page is not loaded and scrolling animation is active. I have created a large viewpager2 with 100 pages containing Recyclerview.
My Activity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TabLayout tabLayout = findViewById(R.id.tabLayout);
ViewPager2 viewPager = findViewById(R.id.viewPager2);
viewPager.setAdapter(new viewPagerAdapter(this));
new TabLayoutMediator(tabLayout, viewPager, true, true,
((tab, position) -> tab.setText("Page: " + position))).attach();
}
private class viewPagerAdapter extends FragmentStateAdapter {
public viewPagerAdapter(FragmentActivity fa) {
super(fa);
}
#Override
public Fragment createFragment(int position) {
Fragment fragment = new itemFragment();
Bundle args = new Bundle();
args.putInt(itemFragment.ARG_PARAM1, position);
fragment.setArguments(args);
return fragment;
}
#Override
public int getItemCount() {
return 100;
}
}
}
My Fragment
public class itemFragment extends Fragment {
public static final String ARG_PARAM1 = "parram1";
int pagePosition;
public itemFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
pagePosition = getArguments().getInt(ARG_PARAM1);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.frgment_item, container, false);
return view;
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
TextView textView = view.findViewById(R.id.textView);
textView.setText("Page - " + pagePosition);
RecyclerView recyclerView = view.findViewById(R.id.recyclerView);
recyclerView.setAdapter(new myAdapter());
recyclerView.setLayoutManager(new GridLayoutManager(getContext(), 16));
}
private class myAdapter extends RecyclerView.Adapter<Myvh> {
#Override
public Myvh onCreateViewHolder(ViewGroup parent, int viewType) {
return new Myvh(new TextView(getContext()));
}
#Override
public void onBindViewHolder(Myvh holder, int position) {
int codepoint=pagePosition*700 + position;
char[] ch=Character.toChars(codepoint);
holder.textView.setText(String.valueOf(ch));
}
#Override
public int getItemCount() { return 700; }
}
private class Myvh extends RecyclerView.ViewHolder {
TextView textView;
public Myvh(View itemView) {
super(itemView);
textView = (TextView) itemView;
}
}
}
I have also tried Recyclerview adapter instead of FragmentStateAdapter and getting same problem.
I have found some solution but not sufficient.
Those are:
Using old ViewPager(deprecated)
Using viewPager.setOffscreenPageLimit(100); (taking huge time to load activity)
Disabling smoothscroll ( looks awful when swiping)

Android: Sending a cardview from one fragment to another

I need some help for a summer project
This is my Events fragment
This is my MyList fragment
I'm using a RecyclerView+Cardview to display the Events. The idea is that the user can click the big plus on the right side of each card, and the card would be displayed in the MyList fragment. I would like to ask if it's possible to transfer a card directly from one fragment to another? Also, both fragments are contained within the same activity, which makes it a little trickier(I haven't found any available solutions).
If that is not possible, another way is to transfer the reference type object contained in the CardView to the MyList fragment. However, this is even less straightforward. This is because the button is inflated in the adapter, but there is no reference type object created here. I have seen many tutorials on using the Parcelable interface, however, I don't know how to implement it here when I'm unable to even create the object in the adapter. The reference object is created in another activity and stored in Firebase before it is read and displayed.
I'm going to attach my EventsAdapter.java and EventsItem.java and EventsFragment.java code below, but please let me know if I should include more code to describe the problem.
Thanks for reading my very long post!!
public class EventsAdapter extends RecyclerView.Adapter<EventsAdapter.EventsViewHolder> implements Filterable {
private ArrayList<EventsItem> mEventsList;
private ArrayList<EventsItem> mEventsListFull;
private EventsAdapter.OnItemClickListener mListener;
private Context mContext;
private DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.UK);
public interface OnItemClickListener {
void onItemClick(int position);
}
//the ViewHolder holds the content of the card
public static class EventsViewHolder extends RecyclerView.ViewHolder {
public ImageView mImageView;
public ImageView mAddButton;
public TextView mTextView1;
public TextView mTextView2;
public TextView mTextView3;
public TextView mTextView4;
public TextView mTextView5;
public EventsViewHolder(Context context, View itemView, final EventsAdapter.OnItemClickListener listener) {
super(itemView);
final Context context1 = context;
mImageView = itemView.findViewById(R.id.imageView);
mAddButton = itemView.findViewById(R.id.image_add);
mTextView1 = itemView.findViewById(R.id.title);
mTextView2 = itemView.findViewById(R.id.event_description);
mTextView3 = itemView.findViewById(R.id.date);
mTextView4 = itemView.findViewById(R.id.location);
mTextView5 = itemView.findViewById(R.id.time);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (listener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
listener.onItemClick(position);
}
}
}
});
mAddButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String str1 = mTextView1.getText().toString();
String str2 = mTextView2.getText().toString();
String str3 = mTextView3.getText().toString();
String str4 = mTextView4.getText().toString();
String str5 = mTextView5.getText().toString();
Bundle bundle = new Bundle();
bundle.putString("title", str1);
bundle.putString("event description", str2);
bundle.putString("date", str3);
bundle.putString("location", str4);
bundle.putString("time", str5);
MylistFragment mlf = new MylistFragment();
mlf.setArguments(bundle);
}
});
}
}
//Constructor for EventsAdapter class. This ArrayList contains the
//complete list of items that we want to add to the View.
public EventsAdapter(Context context, ArrayList<EventsItem> EventsList) {
mEventsList = EventsList;
mContext = context;
mEventsListFull = new ArrayList<>(EventsList); // copy of EventsList for SearchView
}
//inflate the items in a EventsViewHolder
#NonNull
#Override
public EventsAdapter.EventsViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.event_item, parent, false);
EventsAdapter.EventsViewHolder evh = new EventsAdapter.EventsViewHolder(mContext, v, mListener);
return evh;
}
#Override
public void onBindViewHolder(#NonNull EventsAdapter.EventsViewHolder holder, int position) {
EventsItem currentItem = mEventsList.get(position);
holder.mImageView.setImageResource(currentItem.getProfilePicture());
holder.mTextView1.setText(currentItem.getTitle());
holder.mTextView2.setText(currentItem.getDescription());
holder.mTextView3.setText(df.format(currentItem.getDateInfo()));
holder.mTextView4.setText(currentItem.getLocationInfo());
holder.mTextView5.setText(currentItem.getTimeInfo());
}
#Override
public int getItemCount() {
return mEventsList.size();
}
public class EventsItem implements Occasion, Parcelable {
//fields removed for brevity
//constructor removed for brevity
}
public EventsItem() {
}
public EventsItem(Parcel in) {
profilePicture = in.readInt();
timeInfo = in.readString();
hourOfDay = in.readInt();
minute = in.readInt();
locationInfo = in.readString();
title = in.readString();
description = in.readString();
}
public static final Creator<EventsItem> CREATOR = new Creator<EventsItem>() {
#Override
public EventsItem createFromParcel(Parcel in) {
return new EventsItem(in);
}
#Override
public EventsItem[] newArray(int size) {
return new EventsItem[size];
}
};
//getter methods have been removed for brevity
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(profilePicture);
dest.writeString(timeInfo);
dest.writeString(locationInfo);
dest.writeString(title);
dest.writeString(description);
dest.writeString(df.format(dateInfo));
dest.writeInt(hourOfDay);
dest.writeInt(minute);
}
}
public class EventsFragment extends Fragment {
ArrayList<EventsItem> EventsItemList;
FirebaseDatabase mDatabase;
DatabaseReference mDatabaseReference;
ValueEventListener mValueEventListener;
private RecyclerView mRecyclerView;
private RecyclerView.LayoutManager mLayoutManager;
private EventsAdapter mAdapter;
private View rootView;
public FloatingActionButton floatingActionButton;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_events, container, false);
mDatabase = FirebaseDatabase.getInstance();
mDatabaseReference = mDatabase.getReference().child("Events");
createEventsList();
buildRecyclerView();
floatingActionButton = rootView.findViewById(R.id.fab);
floatingActionButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), EventsAdder.class);
startActivity(intent);
}
});
mValueEventListener = new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
EventsItemList.add(snapshot.getValue(EventsItem.class));
}
EventsAdapter eventsAdapter = new EventsAdapter(getActivity(), EventsItemList);
mRecyclerView.setAdapter(eventsAdapter);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
};
mDatabaseReference.addValueEventListener(mValueEventListener);
setHasOptionsMenu(true);
Toolbar toolbar = rootView.findViewById(R.id.events_toolbar);
AppCompatActivity activity = (AppCompatActivity) getActivity();
activity.setSupportActionBar(toolbar);
return rootView;
}
public void createEventsList() {
EventsItemList = new ArrayList<>();
}
public void buildRecyclerView() {
mRecyclerView = rootView.findViewById(R.id.recyclerview);
mLayoutManager = new LinearLayoutManager(getContext());
mAdapter = new EventsAdapter(getActivity(), EventsItemList);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setAdapter(mAdapter);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
}
}

If you would like to see the same CardView within the MyListFragment, you could have the MyListFragment contain a RecyclerView, and reuse the same EventsAdapter and EventsViewHolder. The only difference is that rather than populating the adapter with all the children of the "Events" from your database, you would only populate it with the single Event that you want.
Also, since you have made your Event class implement parcelable, you do not need to manually create the bundle when clicking the plus button.
I am assuming you have a single Activity, and you simply want to replace the EventsFragment with the MyListFragment. Checkout the docs for replacing one fragment with another.
Step 1:
Extend your onItemClickListener to look like:
public interface OnItemClickListener {
void onItemClick(int position);
void onPlusButtonClick(int position);
}
and adjust the code in your EventsViewHolder constructor to look like this when the plus button is clicked:
mAddButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (listener != null) {
// no need to manually create the bundle here
// you already have all the information you need
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
listener.onPlusButtonClick(position);
}
}
}
});
Step 2:
Implement our new method onPlusButtonClick. As per our discussion in the comments, it seems you do not implement this interface anywhere. You can implement it inside the constructor to your EventsAdapter:
public EventsAdapter(Context context, ArrayList<EventsItem> EventsList) {
mEventsList = EventsList;
mContext = context;
mEventsListFull = new ArrayList<>(EventsList); // copy of EventsList for SearchView
mListener = new OnItemClickListener() {
#Override
public void onItemClick() {
// handle clicking the entire view holder
// NOTE: inside your EventsViewHolder, it looks like you call this method on the entire itemView. This could 'swallow' the click on the plus button. You may need to adjust your code to handle this.
}
#Override
public void onPlusButtonClick(int position) {
MyListFragment myListFragment = new MyListFragment();
Event event = mEventsList.get(position);
Bundle bundle = new Bundle();
bundle.putExtra("event", event); // this will work due to implementing parcelable
myListFragment.setArguments(bundle);
// use mContext since im assuming we areinside adapter
// if in an Activity, no need to use context to get the fragment manager
FragmentTransaction transaction = mContext.getSupportFragmentManager().beginTransaction();
// Replace the EventsFragment with the MyListFragment
// and add the transaction to the back stack so the user can navigate back
transaction.replace(R.id.fragment_container, myListFragment);
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}
}
}
Step 3:
Inside your MyListFragments onCreateView() method:
#Override
public View onCreateView (
LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState
) {
Bundle bundle = getArguments();
Event event = bundle.getExtra("event"); // again, will work due to implementing parcelable
// from here you should bind to a recycler view, and you can even reuse your adapter like so:
List<EventsItem> singleEventList = new List<EventsItem>();
singleEventList.add(event);
EventsAdapter adapter = new EventsAdapter(getActivity(), singleEventList);
// be sure to inflate and return your view here...
}
and you should be good to go!
I have left out bits of code here and there for simplicity.. but I hope this is understandable.
As a side note.. in your firebase database listener, it is bad practice to create a new EventsAdapter every single time your data is updated. Instead, you should update the data in the adapter with the new values. Do this by creating a public method inside the adapter such as replaceEvents(List<EventsItem> newEvents), and inside, replace mEventsList with the new events, then call notifyDataSetChanged().

Custom TabLayout in AlertDialog using ViewPager2

I am relatively new to writing apps and I am currently working at my second project. I have an activity called AddNetwork, which contains a button that should open an AlertDialog. In the AlertDialog I want to have a TabLayout with two tabs, that each show different content. I have been trying to achieve this for about 8 hours and I have found a few tutorials that partially cover my problem, but nothing that is really on point. I think I could solve my problem using ViewPager2, but I haven't managed to get it working yet. As of now my code works as follows:
AddNetwork.java creates an instance of AlertDialogSelectWifi.java, which extends DialogFragment and inflates the alertdialog_select_wifi.XML layout file that contains a TabLayoutand a ViewPager2. Also in the DialogFragment, I am trying to set an adapter to the viewPager, namely ViewPagerAdapter.java, which extends FragmentStateAdapter. From there I would want to attach the two fragments AlertDialogRecentFragment.java (with fragment_alert_dialog_recent.xml) and AlertDialogTypeFragment.java (with fragment_alert_dialog_type.xml). Note that the latter is not yet included in the code, so as of now I would only add one fragment to the tabs (I guess).
So at the moment, my code is a somewhat chaotic mixture of all the tutorials I found and followed. It does not cause any errors and I am able to open the Alertdialog, however, the fragment_alert_dialog_recent.xml and the tabs are not visible.
I really don't know what else I could try or change in my code. Overall I am not sure whether it is correct to set the ViewPagerAdapter in the AlertDialogSelectWifi.java file or not. What am I missing or doing wrong? Any help is grealty appreciated!
Here is my code:
AddNetwork.java
public class AddNetwork extends AppCompatActivity {
Context context = this;
#Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_network);
//BUTTON
final MaterialButton buttonSelectWifi;
buttonSelectWifi = (MaterialButton) findViewById(R.id.button2);
buttonSelectWifi.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//CREATE ALERT DIALOG
FragmentManager fm = getSupportFragmentManager();
DialogFragment dialog = AlertDialogSelectWifi.newInstance(context);
dialog.show(fm, "dialog");
}
});
}
}
AlertDialogSelectWifi.java
public class AlertDialogSelectWifi extends DialogFragment {
static Context mContext;
public static AlertDialogSelectWifi newInstance(Context context) {
mContext = context;
return new AlertDialogSelectWifi();
}
#NonNull
#Override
public Dialog onCreateDialog(#Nullable Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity(), R.style.AlertDialogTheme);
LayoutInflater inflater = requireActivity().getLayoutInflater(); //getActivity().getLayoutInflater();
View alertLayout = inflater.inflate(R.layout.alertdialog_select_wifi, null);
builder.setTitle("Add Saved Network")
.setView(alertLayout)
.setCancelable(true)
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
return builder.create();
}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.alertdialog_select_wifi, container, false);
return view;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ViewPager2 viewPager = view.findViewById(R.id.viewpager);
TabLayout tabLayout = view.findViewById(R.id.tablayout);
ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity(), mContext, viewPager);
viewPager.setAdapter(adapter);
new TabLayoutMediator(tabLayout, viewPager,
new TabLayoutMediator.TabConfigurationStrategy() {
#Override
public void onConfigureTab(#NonNull TabLayout.Tab tab, int position) {
tab.setText("Tab " + (position + 1));
}
}).attach();
}
}
ViewPageAdapter.java
public class ViewPagerAdapter extends FragmentStateAdapter {
private LayoutInflater mInflater;
private ViewPager2 viewPager;
public ViewPagerAdapter(FragmentActivity fragmentActivity, Context context, ViewPager2 viewPager) {
super(fragmentActivity);
this.mInflater = LayoutInflater.from(context);
this.viewPager = viewPager;
}
#NonNull
#Override
public Fragment createFragment(int position) {
return AlertDialogRecentFragment.newInstance();
}
#Override
public int getItemCount() {
return 0;
}
}

if i understood your problem correctly change your adapter like this:
public class ViewPagerAdapter extends FragmentStateAdapter {
public ViewPagerAdapter(FragmentActivity fragmentActivity) {
super(fragmentActivity);
}
#NonNull
#Override
public Fragment createFragment(int position) {
if(position == 0)
return new AlertDialogRecentFragment();
else
return new AlertDialogTypeFragment();
}
#Override
public int getItemCount() {
return 2;
}
}

Where to place EventBus.getDefault().unregister in BaseAdapter

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.