I'm new to firebase database and firebase in general and I encountered a little issue while trying to work with it.
I am using the following JSON code I imported from firebase console, originally I just created a database structure in firebase console then downloaded the JSON code, and it is as follows:
{
"rides" : {
"arrive" : "kech",
"depart" : "agadir",
"detail" : "0,1",
"msg" : false,
"phone" : true,
"price" : 15,
"profile_id" : 0,
"spots" : 3,
"timedate" : "11/12/2017 11:15",
"vocal_id" : 0
}
}
The object i want to fetch is named Ride.java:
public class Ride {
private String arrive;
private String depart;
private String detail;
private boolean msg;
private boolean phone;
private int price;
private int profile_id;
private int spots;
private String timedate;
private int vocal_id;
public Ride() {}
// public getters (I created them I just didn't post it all to make the post shorter)
}
To listen to my database reference I'm using the following code:
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("rides").child("0"); // 0 is the ride id
ref.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Ride ride = singleSnapshot.getValue(Ride.class);
rides.add(ride); // list of rides used later in a listadapter
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.e(TAG, "onCancelled", databaseError.toException());
}
});
I'm trying to fetch a single ride from firebase db and show it in my app. In firebase console it has the url: https://myapp.firebaseio.com/rides/0 (the second ride has id 1 and so on). What is the best practice to grab all rides and from each ride access its attributes?
Edit: When I remove .child("0") I do not get any errors but nothing appears in my listView. Apparently rides.add(ride) doesn't take place for some reason.
I tested it by adding a simple instance of Ride outside the addListenerForSingleValueEvent() method, it works fine.
I also tried changing the listener to addValueEventListener(), same result..
Edit2: I get an error message when I try to retrieve Integers from my database.
I tried this in my database listener:
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot singleSnapshot: dataSnapshot.getChildren()) {
int price = (int) singleSnapshot.child("price").getValue(); // error takes place here
Log.d("FirebaseDb", String.valueOf(price));
}
}
The result is this error: (with all ints)
java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer
at com.ride.ive.anas.iveride.Fragments.RidesFragment$1.onDataChange(RidesFragment.java:96)
But when I retrieve a String or a Boolean it works fine, as in:
String arrive = (String) singleSnapshot.child("arrive").getValue();
Or Boolean usePhone = (Boolean) singleSnapshot.child("phone").getValue();
Edit3: Here is the RidesFragment.java file upon request by @Prodigy.
In which I have a ListView where I try to show all Ride instances stored in my firebase database.
public class RidesFragment extends Fragment {
ListView list;
RidesAdapter2 ridesAdapter;
List<Ride> rides;
Ride ride;
List<RidePojo> filteredRides;
LinearLayout layoutFilter;
boolean filtersVisible = false;
boolean searchDone = false;
String userNumber;
public RidesFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_rides, container, false);
getActivity().setTitle("Search for a ride:");
// filter action button stuff
setHasOptionsMenu(true);
layoutFilter = rootView.findViewById(R.id.ll_filter_screen);
/*FragmentManager fm = getActivity().getSupportFragmentManager();
fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);*/
ridesAdapter = new RidesAdapter2(getContext(), rides);
Bundle arguments = getArguments();
list = rootView.findViewById(R.id.rides_list);
rides = new ArrayList<>();
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("rides");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot singleSnapshot: dataSnapshot.getChildren()) {
Ride ride = singleSnapshot.getValue(Ride.class);
rides.add(ride);
ridesAdapter.notifyDataSetChanged();
Log.d("FbDatabase", singleSnapshot.toString());
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.e(TAG, "onCancelled", databaseError.toException());
}
});
rides.add(ride);
// In case the rides ArrayList is not empty another fragment appears for no rides criteria
if(rides.isEmpty()) {
rootView = inflater.inflate(R.layout.fragment_empty, container, false);
Button rideButton = rootView.findViewById(R.id.btn_post_ride);
Button requestButton = rootView.findViewById(R.id.btn_post_request);
rideButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
launchFragment(new OfferRideFragment(), getActivity());
}
});
requestButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
launchFragment(new RequestFragment(), getActivity());
}
});
}
else {
list.setAdapter(ridesAdapter);
}
return rootView;
}
protected void launchFragment(Fragment f, FragmentActivity a) {
android.support.v4.app.FragmentTransaction fragmentTransaction =
a.getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, f);
fragmentTransaction.commit();
}
// ....
}
