I want to be able to query the tags from each category eg, Shirts, Pants , etc. In my firebase console i only have Shirts for now.
In my app recouture i have currently 2 users using and a Shirts node. Ideally there would be other categories added to it as well. Eg, Pants, Shoes
I would like for each user to conduct a query on the tags under each category and each would have a similar structure to Shirts.
Hope my question was clear !
Try the following:
FirebaseUser user=FirebaseAuth.getInstance().getCurrentUser();
DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child(user.getUid()).child("Shirts");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds: dataSnapshot.getChildren()){
DataSnapshot tags=ds.child("tags");
for(DataSnapshot datas: tags.getChildren()){
String tagValues=datas.getValue().toString();
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Here you snapshot is at Shirts then you loop and to be able to access the child tags, then you loop inside the node tags and retrieve the values Style and Tags.
Related
Here is my Database architecture where Jobs is the main child and under that there will be users child, and an user can post multiple time. now i want to get all the posts done by all the users at once. is it possible to do that?
https://i.stack.imgur.com/DT3MO.jpg
setQuery(FirebaseDatabase.getInstance().getReference().child("Jobs")
Used that query to get all of the posts from all of the users but didnt work. any better solution for this problem?
setQuery(FirebaseDatabase.getInstance().getReference().child("Jobs").child("Uid");
this one works but cant use this one because i want to set free for all users to read data.
You can do the following:
DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Jobs");
reference.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()){
String key = ds.getKey();
for (DataSnapshot childSnapshot: ds.getChildren()) {
// get the child attribute under the random key
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException();
}
});
Since you have a reference to node Jobs then in the first iteration you can get the random keys (highlighted in your image), and in the second iteration you can get the attributes inside those keys.
how email's value change from "app-user/users"?
Firebase state :
this isn't web language, i use javacode and xml of androidstudio.
i'm tryed under code.
databaseReference.child(app-user).child(user).orderByChild("email").equalTo("user4~~")
I don't know what to do next.
To get all users whose email address starts with user4:
DatabaseReference usersRef = FirebaseDatabase.getInstance().getReference().child("app-users/users");
Query usersQuery = usersRef.orderByChild("email").startAt("user4").endAt("user4\uF7FF");
usersQuery.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot userSnapshot: dataSnapshot.getChildren()) {
System.out.println(userSnapshot.getKey()+": "+userSnapshot.getChild("displayName").getValue(String.class));
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException();
}
}
To understand the usersRef.orderByChild("email").startAt("user4").endAt("user4\uF7FF") query, read it as:
Take all child nodes of usersRef and order them by their email property.
Then find the first child node that starts with user4.
Then return each child node, until you find a child that starts with .endAt("user4\uF7FF") (or further).
In this the \uF7FF is no magic code, but just the last known Unicode character. So by combining .startAt("user4").endAt("user4\uF7FF"), you're building a startsWith operator.
How do I display the RequestsID on a recyclerview only when stallID = 1?
How should my DatabaseReference be?
update:
Your database structure would not support orderByChild() from top node. So you would have to set your database reference upto the node food and then you can use orderByChild() query to find the Childs with certain stallID.
This, in code would look something like this:
DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Requests").child("1542..").child("foods");
ref.orderByChild("stallID").equalTo(stallIDYouWant).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot ds : dataSnapshot.getChildren()){
// do here what you wanted
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
// ToDo: don't ignore this, do something for errors
}
)};
This would in fact not help you much because you'd have to set this for every unique id in your database structure.
So the better thing to do here would be make your database structure different. To know more how to make your structure good for this operation, refer this answer.
I'm trying to get data which has current user uid and sort by time, but somehow my query brings data which has other uid as well
This is my query
FirebaseDatabase.getInstance().getReference().child("posts").orderByChild("uid_timestamp/"+uid).limitToLast(12)
.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
items.clear();
for (DataSnapshot item : dataSnapshot.getChildren()) {
items.add(item.getValue(PostModel.class));
Log.d("checking","writerUid "+item.getValue(PostModel.class).writerUid);
}
This is my database
So the writerUid is in uid_timestamp with the time. Am I using wrong child key? I need your help!
I am trying to retrieve a list of friends for a user so I can display them in a list view. The friends and user info is structured like this in my firebase database:
So basically, I want to take the user ids listed in the friends part and query my users data to get all the info under every node that is in that set of user ids. How can I achieve this using the android firebase database sdk querying? I would like to be able to retrieve all the users in a single database query.
Thanks.
You cannot get that data in single query, you need to query your database twice. This is a common practice when it comes to Firebase. Assuming that friends and users nodes are direct childs of your Firebase root, to achieve this, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference friendIdRef = rootRef.child("friends").child(friendId)
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String key = ds.getKey();
DatabaseReference usersRef = rootRef.child("users").child(key);
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot dSnapshot : dataSnapshot.getChildren()) {
String username = dSnapshot.child("username").getValue(String.class);
Log.d("TAG", username);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
usersRef.addListenerForSingleValueEvent(eventListener);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
friendIdRef.addListenerForSingleValueEvent(valueEventListener);
It will print all user names of those particular users. One more thing to note, is that you don't need to add in your database those friends that have the value of false, only those with the value of true.