I have been making a project using firebase for a delivery system app.
Problem: In this image, I need to get these two keys(or parent I think) and store them in a string or if possible I just want to know if I can check if the Id in user has a duplicate. How to check if these key has duplicate or exist and store it on a string if it does exist.
Updated code,
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_manageordergrocery);
mRecyclerView2= findViewById(R.id.recyclerview1);
mRecyclerView2.setHasFixedSize(true);
mRecyclerView2.setLayoutManager(new LinearLayoutManager(this));
mModel2 = new ArrayList<>();
mAuth = FirebaseAuth.getInstance();
FirebaseUser user = mAuth.getCurrentUser();
mAdapter2=new ViewHolder1(Manageordergrocery.this, mModel2);
mRecyclerView2.setAdapter(mAdapter2);
mDatabaseReference2= FirebaseDatabase.getInstance().getReference("Users");
mDatabaseReference2.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot postSnapshot:dataSnapshot.getChildren())
{
String myParentNode = postSnapshot.getKey();
mDatabaseReference2 = FirebaseDatabase.getInstance().getReference();
mDatabaseReference2.orderByKey().equalTo(myParentNode).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
String saveNode = dataSnapshot.getKey();
mDatabaseReference2 = FirebaseDatabase.getInstance().getReference(saveNode).child("Ordered");
mDatabaseReference2.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot postSnapshot:dataSnapshot.getChildren()) {
Model1 model2 = postSnapshot.getValue(Model1.class);
mModel2.add(model2);
}
mAdapter2.notifyDataSetChanged();
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Toast.makeText(Manageordergrocery.this, databaseError.getMessage(), Toast.LENGTH_LONG).show();
}
});
}
Can someone help me, please? I'm still new in firebase and don't know how to do it.
To obtain the two keys you can do the following:
mDatabaseReference2 = FirebaseDatabase.getInstance().getReference("User");
mDatabaseReference2.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot postSnapshot:dataSnapshot.getChildren())
{
String myParentNode = postSnapshot.getKey();
mDatabaseReference = FirebaseDatabase.getInstance().getReference();
mDatabaseReference.orderByKey().equalTo(myParentNode).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for(DataSnapshot posts :dataSnapshot.getChildren())
{
String key = posts.getKey();
if(key.equals(myParentNode))
Toast.makeText(Manageordergrocery.this,"equals", Toast.LENGTH_LONG).show();
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {}
});
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Toast.makeText(Manageordergrocery.this, databaseError.getMessage(), Toast.LENGTH_LONG).show();
}
});
Here first you add a reference to node User
then you loop inside that node and retrieve the key
using getKey()
. After that you attach another listener to the root location and using orderByKey().equalTo(myParentNode)
you can check if you have two keys with the same value and do the required.