Each user in my app can send and get friend requests. When the user checks his friends requests, I want the app to go through each user who sent him a friend request and retrieve his information from the Realtime Database.
This is my code in order to accomplish this:
public void check_For_Friends_And_Requests(){
String loggedUser=SaveSharedPreference.getLoggedEmail(getApplicationContext());
final DatabaseReference mDatabase= FirebaseDatabase.getInstance().getReference();
final DatabaseReference userRef=mDatabase.child("Users").child(loggedUser);
userRef.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
final List<User> friendRequestsReceived_UserList=new ArrayList<>();
for (DataSnapshot postSnapshot: dataSnapshot.child("friend_requests_received").getChildren()) {
final String senderEmail=postSnapshot.getKey();
Toast.makeText(getApplicationContext(),
senderEmail, Toast.LENGTH_SHORT).show();
if (senderEmail!=null){
mDatabase.child("Users").child(senderEmail).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Toast.makeText(getApplicationContext(),
dataSnapshot.child("name").getValue(String.class), Toast.LENGTH_SHORT).show();
friendRequestsReceived_UserList.add(
new User(
senderEmail,
dataSnapshot.child("name").getValue(String.class),
dataSnapshot.child("level").getValue(Integer.class),
dataSnapshot.child("skill").getValue(Double.class)));
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
UserListAdapter friendRequestsReceived_Adapter =
new UserListAdapter(getApplicationContext(),
R.layout.friend_requests_received_listview_row,
friendRequestsReceived_UserList);
friendRequestsReceived_ListView.setAdapter(friendRequestsReceived_Adapter);
}
else
connectionErrorGoToMain();
}
@Override
public void onCancelled(DatabaseError databaseError) {
connectionErrorGoToMain();
}
});
}
I have in this code 2 ValueEventListeners. I add the user information to the list in the inner one. The problem is that the list is empty at the end of this process.
I would like to fill a list view with this information using these lines:
UserListAdapter friendRequestsReceived_Adapter =
new UserListAdapter(getApplicationContext(),
R.layout.friend_requests_received_listview_row,
friendRequestsReceived_UserList);
friendRequestsReceived_ListView.setAdapter(friendRequestsReceived_Adapter);
When I put them inside the innner listener, it works fine, but I don't want to set the adapter for each user in the list, only after the for loop.
I'm attaching a screenshot with my database structure (I don't need to get all of the parameters):
