How do i display elements from Firebase such as "FIELD1" in android? - android

As the title says, i just cannot find a solution. What I've tried so far, results in no success.
Here's a link to an image below.


If you want to get only the value of the FIELD1 property under node 7, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference fieldOneRef = rootRef.child("Ada").child("7").child("FIELD1");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String field1 = dataSnapshot.getValue(String.class);
Log.d(TAG, field1);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage());
}
};
fieldOneRef.addListenerForSingleValueEvent(valueEventListener);
And if you want to get the value of the FIELD1 property under all nodes, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference adaRef = rootRef.child("Ada");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String field1 = ds.child("FIELD1").getValue(String.class);
Log.d(TAG, field1);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage());
}
};
adaRef.addListenerForSingleValueEvent(valueEventListener);

Related

Firebase android get all from table

I need some help.
I have a realtime database in firebase. I need to bring all records from this table.
After already setting the connection, I tried the command:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference usersRef = rootRef.child("rlmb-loterias");
I need the whole contents of the table and generate an array or a json

first you have to get all the keys and then you can get table values like this :-
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference usersRef = rootRef.child("rlmb-loterias");
usersRef .addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot snap : dataSnapshot.getChildren()){
usersRef.child(snap.getKey()).addListenerForSingleValueEvent(new
ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
String data = dataSnapshot.getValue();
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
//enter code here
}
});
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
//enter code here
}
});

In order to get the keys and the corresponding values, you need to attach a listener on your reference. Assuming that the rlmb-loterias node is not your root node, please use the following lines of code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference rlmbLoteriasRef = rootRef.child("rlmb-loterias");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String key = ds.getKey();
String value = ds.getValue(String.class);
Log.d(TAG, key + " / " + value);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage()); //Don't ignore errors!
}
};
rlmbLoteriasRef.addListenerForSingleValueEvent(valueEventListener);
If your rlmb-loterias node is your root key, then simply attach the listener on the rootRef:
rootRef.addListenerForSingleValueEvent(valueEventListener);

How do I read all the routeUp objects?

I want to read routeUp node`s all the objects.How can I read it?
This is the database :
enter image description here

To get all the object within your routeUp node, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference routeRef = rootRef.child("route");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot dSnapshot : dataSnapshot.getChildren()) {
for(DataSnapshot ds : dSnapshot.child("routeUp").getChildren()) {
String haltName = ds.child("haltName").getValue(String.class);
Log.d(TAG, haltName);
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage());
}
};
routeRef.addListenerForSingleValueEvent(valueEventListener);
The output in your logcat will be:
Kaduwela
//an so on

How to search through data in firebase android from given structure

I want to search through data in firebase like here:
I have already tried, but it not works
//Query query = FirebaseDatabase.getInstance().getReference(uid).orderByChild("title").startAt(editable.toString()).endAt(editable.toString()+"\uf888");
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("categoreis");
Query query = FirebaseDatabase.getInstance().getReference("categoreis").limitToFirst(4).orderByChild("image");
query.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
list.clear();
for (DataSnapshot data:dataSnapshot.getChildren())
{
for (DataSnapshot ds:data.child("SubAccessories").getChildren())
{
for (DataSnapshot ds1:ds.getChildren())
{
//Log.d("checkData1",ds1.toString());
//Log.d("checkData1",ds1.child("image").getValue(String.class));
}
}
}

If you want to get the image as I see in your question, please use the following lines of code but assuming that the categories node is a direct child of your Firebase database root:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference ref = rootRef.child("categories/Accessories/SubAccessories/Accessories/Grab Bar");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String image = dataSnapshot.child("image").getValue(String.class);
Log.d("TAG", image);
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
ref.addListenerForSingleValueEvent(valueEventListener);
According to your comment, you should loop through the second Accessories node using getChildren() method like this:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference ref = rootRef.child("categories/Accessories/SubAccessories/Accessories");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String image = dataSnapshot.child("image").getValue(String.class);
Log.d("TAG", image);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
ref.addListenerForSingleValueEvent(valueEventListener);

Get linked data from Firebase

My firebase structure looks like this:
The groups use keys generated by firebase, 0 and 1 are just examples.
In those groups there is more data like "groupname".
How should I retrieve the groupnames of all groups linked to a user?
I'm on Android.
Solved by Alex.

Assuming that the groups node is a direct child of your Firebase root and inside a single group, there is a key named groupName, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference groupsRef = rootRef.child("groups");
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String name = ds.child("name").getValue(String.class);
Log.d("TAG", name);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.d("TAG", task.getException().getMessage()); //Never ignore potential errors!
}
};
groupsRef.addListenerForSingleValueEvent(eventListener);
If you need to be able to get only the group names of the groups that your users are linking to, you need to query twice like this:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference userGroupsRef = rootRef.child("users").child(userKey).child("groups");
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String groupKey = ds.getKey();
DatabaseReference groupKeyRef = rootRef.child("groups").child(groupKey);
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String name = dataSnapshot.child("name").getValue(String.class);
Log.d("TAG", name);
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.d("TAG", task.getException().getMessage()); //Never ignore potential errors!
}
};
groupKeyRef.addListenerForSingleValueEvent(valueEventListener);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.d("TAG", task.getException().getMessage()); //Never ignore potential errors!
}
};
userGroupsRef.addListenerForSingleValueEvent(eventListener);
In which userKey is the key of the user from which you want the get the group ids.

Firebase Query get values

I have a list of Child-Data and wants to have a certain value.
My Firebase structure:
Now, I only have the Child "Text" and the currendUser "0zwtyRwgnogC8Qk91AtHj7amZb63"
So how can I get the values of "text and "user_id"?
My source code:
mDatabaseText = FirebaseDatabase.getInstance().getReference().child("Text");
query = mDatabaseText.startAt(mCurrentUser.getUid());
query.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
for (DataSnapshot textSnapshot : dataSnapshot.getChildren()) {
/* String text = textSnapshot.getKey();
Toast.makeText(getActivity(), text, Toast.LENGTH_SHORT).show(); */
TextModel textModel = chatSnapshot.getValue(TextModel.class);
String t = textModel.getText();
Log.i("!!!!!!!text", t);
Toast.makeText(getActivity(), t, Toast.LENGTH_SHORT).show();
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
But this code doesn't work, why?
I used the query startAt.

Please use this code:
FirebaseDatabase rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference currentUserIdRef = rootRef.child("Text").child(currentUserId);
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String userId = (String) ds.getKey();
DatabaseReference userIdRef = rootRef.child("Text").child(currentUserId).child(userId);
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String user_id = (String) dataSnapshot.child("user_id").getValue();
}
#Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException(); // don't ignore errors
}
};
userIdRef.addListenerForSingleValueEvent(eventListener);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException(); // don't ignore errors
}
};
currentUserIdRef.addListenerForSingleValueEvent(eventListener);
In which currentUserId is the variable that you say you already have it.
Hope it helps.

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