Firebase just silently don't get the data.
I work on it a lot of time but still don't really understand what is a problem.
Probably it's very simple mistake so get my excuses please
fRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
ids = dataSnapshot.child("dictionary").child("fruitIds").getValue(DictionaryIDs.class);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
DictionaryIds.class code
package com.example.asuper.mluvitslova;
import com.google.firebase.database.FirebaseDatabase;
import java.util.ArrayList;
public class DictionaryIDs {
private ArrayList<String> fruitIds = new ArrayList<>();
public DictionaryIDs() {
}
public DictionaryIDs(ArrayList<String> fruitIds) {
this.fruitIds = fruitIds;
}
public void addFruitId(String id){
fruitIds.add(id);
}
public ArrayList<String> getFruitIds(){
return fruitIds;
}
public void setFruitIds(ArrayList<String> fruitIds){
this.fruitIds = fruitIds;
}
}
And in log just NOTHING
This code must just get me the DictionaryIds.class file but in fact Firebase just get me null object.
Firebase database structure
Under the last fruitIds child, there are no DictionaryIDs objects, there are simple strings. To get all those ids, you need to loop through the DataSnapshot object using getChildren() method like this:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference fruitRef = rootRef.child("dictionary").child("fruitIds").child("fruitIds");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String id = ds.getValue(String.class);
Log.d(TAG, id);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage());
}
};
fruitRef.addListenerForSingleValueEvent(valueEventListener);
The result in your logcat will be all those ids.
Related
Here is my Firebase Realtime Database structure:
I want to retrieve each and every image in a child(images1,images2,images3,images4 are the child names)
private void loadmybanners1() {
DatabaseReference ref = FirebaseDatabase.getInstance().getReference("BannerImages");
ref.orderByChild("images2").addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot snapshot) {
for (DataSnapshot ds : snapshot.getChildren()) {
final String myImg1 = "" + ds.child("image").getValue();
try{
Picasso.get().load(myImg1).networkPolicy(NetworkPolicy.OFFLINE).into(ban2Iv, new Callback() {
#Override
public void onSuccess() {
}
#Override
public void onError(Exception e) {
Picasso.get().load(myImg1).into(ban2Iv);
}
});
} catch (Exception e) {
ban2Iv.setImageResource(R.drawable.ic_image);
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});
I have used this code to retrieve the image2. But from that, I can only retrieve the images1 child data. What are the modifications to do?
I want to retrieve each and every image in a child
To get each and every child within your BannerImages node, there is no need to use a query, you can simply use a DatabaseReference, as in the following lines of code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference bannerImagesRef = rootRef.child("BannerImages");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String myImg1 = dataSnapshot.child("images1").child("image").getValue(String.class);
Picasso.get().load(myImg1)
String myImg2 = dataSnapshot.child("images2").child("image").getValue(String.class);
Picasso.get().load(myImg2)
//And so on for the other images3, images4, and images5 children
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d("TAG", databaseError.getMessage()); //Don't ignore errors!
}
};
bannerImagesRef.addListenerForSingleValueEvent(valueEventListener);
Add this dependency
implementation 'com.github.bumptech.glide:glide:4.10.0'
After getting Url from Firebase.Just Use below line
Glide.with(context).load(Firbase Url).into(imageView);
ccontacts = new ArrayList<>();
DatabaseReference dbGelenler = db.getReference("Filmler");
dbGelenler.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot gelenler:dataSnapshot.getChildren()){
ccontacts.add(new Data(gelenler.getValue(Film.class).getAciklama(),gelenler.getValue(Film.class).getBen(),gelenler.getValue(Film.class).getImdb(),gelenler.getValue(Film.class).getIsim(),gelenler.getValue(Film.class).getIzlemeLinki(),gelenler.getValue(Film.class).getKategori(),gelenler.getValue(Film.class).getNe(),gelenler.getValue(Film.class).getService(),gelenler.getValue(Film.class).getTrailer(),gelenler.getValue(Film.class).getUrl(),gelenler.getValue(Film.class).getWhat(),gelenler.getValue(Film.class).getYear()));
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
for (Data d:ccontacts){
b.setText(d.getIsim());
}
When I directly set the text via gelenler.getValue() it works, however when I want to populate an ArrayList with this information it fails and receives null. Any help would be appreciated.
I need to get data from a table and use it as a reference in order to get another data in another table.
Here is my table structure
Here is how I get the data in java class.IN my table, I have stored an attribute called 'theraid' which I need to retrieve it and use it as a reference in order to get another attribute named 'name' in another table.
a=new ArrayList<AppointmentObject>();
namelist=new ArrayList<String>();
databaseReference= FirebaseDatabase.getInstance().getReference().child("appointment");
databaseReference.orderByChild("userid").equalTo(userid1).addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull final DataSnapshot dataSnapshot) {
for(DataSnapshot dataSnapshot1: dataSnapshot.getChildren()) {
AppointmentObject thera= dataSnapshot1.getValue(AppointmentObject.class);
a.add(thera);
final String theraid = dataSnapshot1.child("theraid").getValue().toString();
refThera = FirebaseDatabase.getInstance().getReference().child("alluser").child("thera");
refThera.child(theraid).addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot3) {
for (DataSnapshot ds: dataSnapshot3.getChildren())
{
***************error this line below********************************
String text = ds.child("name").getValue().toString();
namelist.add(text);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Toast.makeText(getApplicationContext(), "Oh no!", Toast.LENGTH_SHORT).show();
throw databaseError.toException();
}
});
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Toast.makeText(getApplicationContext(), "Oh no!", Toast.LENGTH_SHORT).show();
}
});
adapter=new MyRecyclerviewPAppointment(MainActivityPAppointment.this, a,namelist);
rv.setAdapter(adapter);
Here is the recyclerview class in order to display the data that retrieve via the java class.
public class MyRecyclerviewPAppointment extends RecyclerView.Adapter<MyRecyclerviewPAppointment.MyViewHolder> {
private Context context;
ArrayList<AppointmentObject> alist;
ArrayList<String> namelist1;
public MyRecyclerviewPAppointment(Context c, ArrayList<AppointmentObject> t,ArrayList<String> namelist) {
context = c;
alist = t;
namelist1=namelist;
}
#Override
public void onBindViewHolder(#NonNull final MyRecyclerviewPAppointment.MyViewHolder holder,final int position) {
holder.tdate.setText(alist.get(position).getDate());
holder.ttime.setText(alist.get(position).getTiming());
holder.tname.setText(namelist1.get(position));
// holder.tstatus.setText(alist.get(position).getTiming());
}
#Override
public int getItemCount() {
return alist.size();
}
}
I don't know what's wrong to my code but it can't work, it just keeps stopped.
Here is the error. May I know where is the mistake in my d=code? Thanks for helping me :).
In the second listener, your databaseReference is at node theraid. Therefore you don't have to loop to be able to access the value of name. So change the following code:
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot3) {
for (DataSnapshot ds: dataSnapshot3.getChildren()) {
String text = ds.child("name").getValue().toString();
namelist.add(text);
}
}
Into this:
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot3) {
String text = dataSnapshot3.child("name").getValue().toString();
namelist.add(text);
}
I want to retrieve only the date and all the date element at once and store them in array in the firebase as shown below.
i have used the following code to retrieve but failed to that.
public void showData(View view) {
final ArrayList<String> date = new ArrayList<>();
firebaseDatabase = FirebaseDatabase.getInstance().getReference().child("Date");
firebaseDatabase.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
date.add(dataSnapshot.getValue().toString());
display.setText(dataSnapshot.getValue().toString());
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
Please help to find a solution for this.
The firebase reference is wrong, you should go from the top node to the date node.
Change this:
firebaseDatabase = FirebaseDatabase.getInstance().getReference().child("Date");
into this:
firebaseDatabase = FirebaseDatabase.getInstance().getReference().child("Name");
firebaseDatabase.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot datas: dataSnapshot.getChildren()){
date.add(datas.child("Date").getValue().toString());
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
Since you want to get all Date then put the firebase reference at the node Name and loop inside the names to be able to retrieve all the dates.
If you want to get the date of one user example Ravi, then you do not need to loop, you can do the following:
firebaseDatabase = FirebaseDatabase.getInstance().getReference().child("Name").child("Ravi").child("Date");
firebaseDatabase.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
date.add(dataSnapshot.getValue().toString());
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
As said by #PeterHaddad in the previous answer, the sequence to access the data you have taken is not right. You may try this way, if nothing else helped until yet.
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
rootRef.child("Names").orderByChild("Date").addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot ds: dataSnapshot.getChildren()){
date.add(ds.getValue(String.class));
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
//Also as you've told that code is not working, please tell, what exactly is not working
I am new in android and I want to get userIDS from Firebase Database, I've tried by using this but it returns null.
By using this code
Value of Constants.ARG_CHAT_GROUP_ROOMS=Groups and Constants.NEW_NODE=newGroup
private void getMYuid() {
String senderUid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference mTest = FirebaseDatabase.getInstance().getReference();
mTest.child(Constants.ARG_CHAT_GROUP_ROOMS).child(Constants.NEW_NODE)
.child(senderUid).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (!dataSnapshot.exists()){
Toast.makeText(ActivityChatView.this, "not exist", Toast.LENGTH_SHORT).show();
Log.e("151","ACV"+dataSnapshot);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Log.e("139","ACV"+senderUid);
}
Database Structure is this
if you want the first one under 15052169227329_myGroupName_Hell By Anne: Your problem is that you forgot the node before "Constants.NEW_NODE"
private void getMYuid() {
String senderUid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference mTest = FirebaseDatabase.getInstance().getReference();
mTest.child(Constants.ARG_CHAT_GROUP_ROOMS).child("15052169227329_myGroupName_Hell By Anne").child(Constants.NEW_NODE)
.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (!dataSnapshot.exists()){
Toast.makeText(ActivityChatView.this, "not exist", Toast.LENGTH_SHORT).show();
Log.e("151","ACV"+dataSnapshot);
}
// You can cast this object later but it seems that that is a string and not an array
Object yourRequiredObject = dataSnapshot.child("usersIDS").getValue();
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Log.e("139","ACV"+senderUid);
}
As i see, it's not an array it's a String. To get the userIDS, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference yourRef = rootRef.child(Constants.ARG_CHAT_GROUP_ROOMS).child(senderUid).child(Constants.NEW_NODE);
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String usersIDS = dataSnapshot.child("usersIDS").getValue(String.class);
Log.d("TAG", usersIDS);
//Here you can split the usersIDS String by , (comma)
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
yourRef.addListenerForSingleValueEvent(eventListener);
In which senderUid is the missing child. This child can have the value like 1505217176288_myGroupName_1 or other coresponding group names.