This loop is fetching 1 key at a time. I want to store all the keys in String[] basically at the end of loop and then use it in ArrayAdapter for auto complete text view.
fdatabaseuser.addValueEventListener(new ValueEventListener({
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String item="";
for (DataSnapshot list: dataSnapshot.getChildren())
{
Object obj= list.getKey();
item=obj.toString();
}
Toast.makeText(GiveActivity.this,item,Toast.LENGTH_LONG).show();
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Actually you already have the keys. You can create an ArrayList and add items.
ArrayList<String> keys = new ArrayList<>();
fdatabaseuser.addValueEventListener(new ValueEventListener({
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String item="";
for (DataSnapshot list: dataSnapshot.getChildren())
{
Object obj= list.getKey();
item=obj.toString();
keys.add(item);
}
Toast.makeText(GiveActivity.this,item,Toast.LENGTH_LONG).show();
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
List<String> item;
Initialise list in the OnCreate Method
item=new ArrayList<>();
Then change this code:
fdatabaseuser.addValueEventListener(new ValueEventListener({
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot list: dataSnapshot.getChildren())
{
Object obj= list.getKey();
item.add(obj.toString();)
}
Toast.makeText(GiveActivity.this,item,Toast.LENGTH_LONG).show();
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
To achieve this, please use the following code:
fdatabaseuser.addValueEventListener(new ValueEventListener({
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
List<String> list = new ArrayList<>();;
for (DataSnapshot ds : dataSnapshot.getChildren()) {
String key = ds.getKey();
list.add(key);
}
Log.d("TAG", list);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
});
Remember, the list must be declared and updated inside the onDataChange() method, otherwise it will be null, due the asynchronous behaviour of onDataChange() which is called even before you are adding those keys to the list.
Related
I'm trying to retrieve nested data from multiple records and display them in a ListView. My data is recorded like so:
I want to display the GroupNumber and the GroupVaccinationDate of all GroupVaccinations recorded in a listView but at the moment the listView remains empty when I run the following code:
listView = (ListView)findViewById(R.id.listItemAllGroupVaccinations);
databaseReference = FirebaseDatabase.getInstance().getReference("groupVaccinations");
groupVaccinations = new ArrayList<>();
protected void onStart(){
super.onStart();
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot groupVaccinationSnapshot : dataSnapshot.getChildren()){
GroupVaccination groupVaccination = groupVaccinationSnapshot.getValue(GroupVaccination.class);
groupVaccinations.add(groupVaccination);
}
AllGroupVaccinationList groupVaccinationInfoAdapter = new AllGroupVaccinationList(ActivityAllGroupVaccinations.this, groupVaccinations);
listView.setAdapter(groupVaccinationInfoAdapter);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
Any help or suggestions would be greatly appreciated!
Gaston's answer will show you all vaccinations in a single group. If instead you want to show all vaccinations in all groups, you can loop over the nested snapshots in your onDataChange:
databaseReference = FirebaseDatabase.getInstance().getReference("groupVaccinations");
groupVaccinations = new ArrayList<>();
AllGroupVaccinationList groupVaccinationInfoAdapter = new AllGroupVaccinationList(ActivityAllGroupVaccinations.this, groupVaccinations);
listView.setAdapter(groupVaccinationInfoAdapter);
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot groupVaccinationSnapshot : dataSnapshot.getChildren()){
for(DataSnapshot vaccinationSnapshot : groupVaccinationSnapshot.getChildren()){
GroupVaccination groupVaccination = vaccinationSnapshot.getValue(GroupVaccination.class);
groupVaccinations.add(groupVaccination);
}
}
groupVaccinationInfoAdapter.notifyDataSetChanged();
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
throw databaseError.toException(); // don't ignore errors
}
});
I also changed the code to call groupVaccinationInfoAdapter.notifyDataSetChanged(), so that you can keep using the same adapter and update it if needed.
You will need to go one level deeper where your id -LZk5tpB5PXqHVJkj8Vz (GroupID) contains all the sub pushKeys (groupVaccinationID) with data inside.
listView = (ListView)findViewById(R.id.listItemAllGroupVaccinations);
databaseReference = FirebaseDatabase.getInstance().getReference("groupVaccinations").child("-LZk5tpB5PXqHVJkj8Vz");
groupVaccinations = new ArrayList<>();
protected void onStart(){
super.onStart();
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot groupVaccinationSnapshot : dataSnapshot.getChildren()){
GroupVaccination groupVaccination = groupVaccinationSnapshot.getValue(GroupVaccination.class);
groupVaccinations.add(groupVaccination);
}
AllGroupVaccinationList groupVaccinationInfoAdapter = new AllGroupVaccinationList(ActivityAllGroupVaccinations.this, groupVaccinations);
listView.setAdapter(groupVaccinationInfoAdapter);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
EDIT
The -LZk5tpB5PXqHVJkj8Vz child should be avoided since is hardcoded to show you this example, instead, you should take that child key from where you get your GroupID, doing that you can get as Frank says all the vaccinations from each GroupID.
I'm facin a really weird problem, Im calling two nodes in my database , from one node I get all my user ids , then I just loop inside my user node to get the user metadata. The problem is that when I run the debugger, it seems like the mAdapter is beign called before the data is beign fetched. So my adapter set the recyclerview with no data. After the adapter has been called, my query fetching the user begins and the array is populated normally
This is what I have done so far
mDatabase.child("teamsNode").child(teamID).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot snapshot : dataSnapshot.getChildren()){
mDatabase.child("users").child(snapshot.getKey()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
UserModel model = dataSnapshot.getValue(UserModel.class);
String playerName = model.getName();
model.setName(playerName);
mArrayPlayers.add(model);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) { }
});
}
mAdapter = new PlayersAdapter(mArrayPlayers,mContext,R.layout.recycler_row);
if(mAdapter.getItemCount()>0)
mRecyclerView.setAdapter(mAdapter);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) { }
});
As you can see, I set the adapter to the recyclerview after the first foreach that fetchs all the data, I know that beign asynchronous I need to wait for the inner mDatabase to be done but if I move the setting of the adapter one line above to wait for the second call to finish it does the same, any idea?
Database structure is like this
teamsNode
|__Jm2KSMjslpow2Ipoasz : true
|__601KSMjsldfjd2Ipos0 : true
|__asgm2Kshalpow2IposJ : true
users
|__Jm2KSMjslpow2Ipoasz
|_____name: randomname1
|__601KSMjsldfjd2Ipos0
|_____name: randomname2
|__asgm2Kshalpow2IposJ
|_____name: randomname3
Recyclerview is not populated. Any idea?
A weird thing is that sometimes runing it with the debugger does fill the data, but its rarely to happend.
If you want to only initialize the adapter when all data is loaded, you will need to do so in the nested onDataChange callback:
mDatabase.child("teamsNode").child(teamID).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshotTeam) {
AtomicInteger loadedUserCount = new AtomicInteger(0);
for(DataSnapshot snapshot : dataSnapshotTeam.getChildren()){
mDatabase.child("users").child(snapshot.getKey()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
UserModel model = dataSnapshot.getValue(UserModel.class);
String playerName = model.getName();
model.setName(playerName);
mArrayPlayers.add(model);
if (loadedUserCount.getAndIncrement() + 1 == dataSnapshotTeam.getChildrenCount()) {
mAdapter = new PlayersAdapter(mArrayPlayers,mContext,R.layout.recycler_row);
if(mAdapter.getItemCount()>0) {
mRecyclerView.setAdapter(mAdapter);
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
throw databaseError.toException(); // don't ignore errors
}
});
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
throw databaseError.toException(); // don't ignore errors
}
});
The problem you have is that the calls to the addListenerForSingleValueEvent methods are asynchronous, so they are executed in another thread. When you call the second addListenerForSingleValueEvent this is executed in another thread, while the main thread follows its execution. You have to do the call of your adapter in the answer of your second call addListenerForSingleValueEvent in the onDataChange method. In this way to avoid anomalous operations of your application.
Hope this will help.
mDatabase.child("teamsNode").child(teamID).addListenerForSingleValueEvent(new ValueEventListener() {
mArrayPalyer.clear();//add this
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot snapshot : dataSnapshot.getChildren()){
mDatabase.child("users").child(snapshot.getKey()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
UserModel model = dataSnapshot.getValue(UserModel.class);
String playerName = model.getName();
model.setName(playerName);
mArrayPlayers.add(model);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
mAdapter = new PlayersAdapter(mArrayPlayers,mContext,R.layout.recycler_row);
mRecyclerView.setAdapter(mAdapter); //makes changes here because you are checking for adapter item count before setting it and this always return null.
}
You can look at my code I am using ValueEventListener just like you and binding the data to recycler view
ValueEventListener postListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()){
UserListModel userListModel =dataSnapshot1.getValue(UserListModel.class);
userModelArrayList.add(userListModel);
}
userListAdapter.notifyDataSetChanged();
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.w(">>value", "loadPost:onCancelled", databaseError.toException());
}
};
//mDatabase is the reference to the Firebase Node
mDatabase.addValueEventListener(postListener);
userListRecyclerView.setLayoutManager(M.gridLayoutRecyclerView(getActivity() , 2));
userListAdapter = new UserListAdapter(getActivity(), userModelArrayList);
userListRecyclerView.setAdapter(userListAdapter);
i wanto get all color data from firebase then insert to arraylist, and the color data structure like image below
and here is when i want to insert to Arraylist
private void getDataDetailProduct() {
imageReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
for (DataSnapshot childSbapshot : dataSnapshot.getChildren()){
String id = childSbapshot.getKey();
ArrayList<String>images = new ArrayList<>();
images.add(String.valueOf(childSbapshot.getChildren()));
}
initSlideImage();
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
ArrayList<String>images = new ArrayList<>();
private void getDataDetailProduct() {
imageReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
for (DataSnapshot childSbapshot : dataSnapshot.getChildren()){
String id = childSbapshot.getKey();
images.add(String.valueOf(childSbapshot.child("colors1").getValue()));
images.add(String.valueOf(childSbapshot.child("colors2").getValue()));
images.add(String.valueOf(childSbapshot.child("colors3").getValue()));
}
initSlideImage();
}}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
I am retrieving data from firebase database inside for loop , but problem is that firebase functions are not execute synchronously , i know firebase functions are asynchronous . is there any solution for that ?
Code :-
registrationReference.child(userId).child("generated_links").addListenerForSingleValueEvent(new ValueEventListener()
{
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
peopleModelList.clear();
for(DataSnapshot snapshot : dataSnapshot.getChildren())
{
peopleModel = new PeopleModel();
peopleHashMap =(HashMap)snapshot.getValue();
peopleModel.setChatWith((String)peopleHashMap.get("chatWith"));
peopleModel.setNickname((String)peopleHashMap.get("nickname"));
peopleModel.setChatRoom(snapshot.getKey());
Log.d("kkkk","1st");
if(peopleModel.getChatWith()!=null && !("".equals(peopleModel.getChatWith())))
{
registrationReference.child(peopleModel.getChatWith()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
peopleModel.setRefresh_token((String)dataSnapshot.child("refresh_token").getValue());
peopleModelList.add(peopleModel);
Log.d("kkkk","2nd");
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
Log.d("kkkk","3rd");
}
iCallBackPeople.peopleAct(peopleModelList);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Output :-
1st
3rd
2nd
But i want output like this
1st
2nd
3rd
Note :-
i searched , but never got any solution !
How to get data from Firebase Database in a loop?
Firebase addListenerForSingleValueEvent excute later in loop
I tried this but not worked for me, it is fill my list with last item !
public void listOfUsers(final ICallBackPeople iCallBackPeople) {
count=0;
//peopleModelList = new ArrayList<>();
sortedMap = new TreeMap<>();
// peopleModelList = new ArrayList<PeopleModel>(sortedMap.values());
registrationReference.child(userId).child("generated_links").addListenerForSingleValueEvent(new ValueEventListener()
{
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
// peopleModelList.clear();
for(DataSnapshot snapshot : dataSnapshot.getChildren())
{
peopleModel = new PeopleModel();
peopleHashMap =(HashMap)snapshot.getValue();
peopleModel.setChatWith((String)peopleHashMap.get("chatWith"));
peopleModel.setNickname((String)peopleHashMap.get("nickname"));
peopleModel.setChatRoom(snapshot.getKey());
//Object chatRoom = snapshot.getKey();
Log.d("kkkk","1st");
if(peopleModel.getChatWith()!=null && !("".equals(peopleModel.getChatWith())))
{
addItem(count,iCallBackPeople);
count++;
}
Log.d("kkkk","3rd");
}
Log.d("kkkk","end");
//iCallBackPeople.peopleAct(peopleModelList);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void addItem(final int index, final ICallBackPeople iCallBackPeople) {
registrationReference.child(peopleModel.getChatWith()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
peopleModel.setRefresh_token((String)dataSnapshot.child("refresh_token").getValue());
Log.d("kkkk","2nd");
sortedMap.put(index, peopleModel);
// sortedMap will sort your list by key (in this case, key is integer)
if(sortedMap.size()==2)
{
peopleModelList = new ArrayList<PeopleModel>(sortedMap.values());
iCallBackPeople.peopleAct(peopleModelList);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
I tried this but not getting all of the item only getting list with last item in snapshot
public void listOfUsers(final ICallBackPeople iCallBackPeople) {
peopleModelList = new ArrayList<>();
registrationReference.child(userId).child("generated_links").addListenerForSingleValueEvent(new ValueEventListener()
{
PeopleModel peopleModel;
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
peopleModelList.clear();
for(final DataSnapshot snapshot : dataSnapshot.getChildren())
{
peopleModel = new PeopleModel();
peopleHashMap =(HashMap)snapshot.getValue();
peopleModel.setChatWith((String)peopleHashMap.get("chatWith"));
peopleModel.setNickname((String)peopleHashMap.get("nickname"));
peopleModel.setChatRoom(snapshot.getKey());
if(peopleModel.getChatWith()!=null && !("".equals(peopleModel.getChatWith())))
{
getToken(new CallBackGetToken() {
#Override
public void token(String token) {
peopleModel.setRefresh_token(token);
Toast.makeText(context, token, Toast.LENGTH_SHORT).show();
peopleModelList.add(peopleModel);
//here i am checking my peopleModelList size is equal or not to snapshot
if(peopleModelList.size()==2)
iCallBackPeople.peopleAct(peopleModelList);
}
},peopleModel);
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void getToken(final CallBackGetToken callBackGetToken ,PeopleModel peopleModel) {
registrationReference.child(peopleModel.getChatWith()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
callBackGetToken.token((String)dataSnapshot.child("refresh_token").getValue());
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
I think you should pass through an interface(create one and implement at this class). the method inside the interface should have a string as a parameter (it will receive your peopleModel.getChatWith() ) .
Inside your if(peopleModel.getChatWith()!=null && !("".equals(peopleModel.getChatWith())))you should request your interface.
I think is a solution for your asynchronously question.
Here is my solution:
int count =0;
SortedMap<Integer,PeopleModel> sortedMap;
private void set() {
count =0;
registrationReference.child(userId).child("generated_links").addListenerForSingleValueEvent(new ValueEventListener()
{
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
peopleModelList.clear();
sortedMap = new TreeMap<>();
for(DataSnapshot snapshot : dataSnapshot.getChildren())
{
peopleModel = new PeopleModel();
peopleHashMap =(HashMap)snapshot.getValue();
peopleModel.setChatWith((String)peopleHashMap.get("chatWith"));
peopleModel.setNickname((String)peopleHashMap.get("nickname"));
peopleModel.setChatRoom(snapshot.getKey());
Log.d("kkkk","1st");
if(peopleModel.getChatWith()!=null && !("".equals(peopleModel.getChatWith())))
{
addItem(count);
count++;
}
Log.d("kkkk","3rd");
}
iCallBackPeople.peopleAct(peopleModelList);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void addItem(final int index) {
registrationReference.child(peopleModel.getChatWith()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
peopleModel.setRefresh_token((String)dataSnapshot.child("refresh_token").getValue());
Log.d("kkkk","2nd");
sortedMap.put(index, peopleModel);
// sortedMap will sort your list by key (in this case, key is integer)
// you can get peopleModelList = new ArrayList<>(sortedMap.values);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
Maybe I'm over simplifying it, but I feel like you should just use simple recursion.
List<People> peopleList;
int currentIndex = 0
private void myFirebaseMethodAction(person){
registerListener.onCallbacks(new ValueListener(){
onDataChanged(){
person.addStufforDoStuff();
if(peopleList.size > currentIndex + 1){
myFirebaseMethodAction(peopleList.get(++currentIndex)
}
}
onFailed(){
//handle it
}
}
}
Does that make sense?
Just saying walk the list with an index, simple.
btw above is pseduo code, don't copy verbatim lol.
I am new to Android Programming. I want to list all child lists from Firebase in Android.
I wrote this code. But When I start the application, the listview returns null.
What am doing wrong?
public class haber_goruntule extends AppCompatActivity {
private ListView liste;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_haber_goruntule);
final List<connector_haber> mesajlar=new ArrayList<connector_haber>();
liste= (ListView) findViewById(R.id.list);
FirebaseDatabase firebaseDatabase=FirebaseDatabase.getInstance();
DatabaseReference ref=firebaseDatabase.getReference();
ref.child("haberler").addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
Iterable<DataSnapshot> children=dataSnapshot.getChildren();
for(DataSnapshot child : children){
connector_haber haber=child.getValue(connector_haber.class);
mesajlar.add(haber);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
final ArrayAdapter<connector_haber> arrayAdapter=new ArrayAdapter<connector_haber>(this,android.R.layout.simple_list_item_1,mesajlar);
liste.setAdapter(arrayAdapter);
}
}
The data is loaded from Firebase asynchronously. By the time it comes back, you're adding it to the adapter, but Android isn't aware of that anymore. To make it aware, call notifyDataSetChanged() after you've added the data:
final ArrayAdapter<connector_haber> arrayAdapter=new ArrayAdapter<connector_haber>(this,android.R.layout.simple_list_item_1,mesajlar);
liste.setAdapter(arrayAdapter);
ref.child("haberler").addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
Iterable<DataSnapshot> children=dataSnapshot.getChildren();
for(DataSnapshot child : children){
connector_haber haber=child.getValue(connector_haber.class);
mesajlar.add(haber);
}
adapter.notifyDataSetChanged(); // tell the adapter to update the view
}
#Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException(); // don't ignore this error
}
});
Try this :
ref.child("haberler").addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
Iterable<DataSnapshot> children=dataSnapshot.getChildren();
for(DataSnapshot child : children){
connector_haber haber=child.getValue(connector_haber.class);
mesajlar.add(haber);
}
final ArrayAdapter<connector_haber> arrayAdapter=new ArrayAdapter<connector_haber>(this,android.R.layout.simple_list_item_1,mesajlar);
liste.setAdapter(arrayAdapter);
}
#Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException(); // don't ignore this error
}
});
well.. there is an open source library for implementing UI with firebase. Try this one FirebaseUI