Collect all data from FirebaseDatabse and call notifyDataSetChanged() once

in brief: I have a list of users ID and I want to iterate over database and find profiles of those users and put them on the list. But I have a problem as follows:

final List<Friend> friendsProfiles = new ArrayList<>();
 for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);
 // The problem is here, because its called as many times as the size of
 // the friendIds list. loadnewData() contains notifyDataSetChanged()
 mFriendsFragment.loadNewData(friendsProfiles);
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 

 
 );
 
 // It gives 0, because it's called before onDatachange()
 // So I can't call loadNewData() here
 Log.d(TAG, updatedFriendsRequestList.size());

How to do it in the nice, proper way?

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

asked Nov 13 '18 at 16:05

northenofca

135

What is the type of your friendIds list?

– Alex Mamo
Nov 13 '18 at 18:04

I simplified the case in sake of better understanding. In original it contains: String friendId and type of the invitation to friends ("sent" or "received"). So it is basically list of objects that contain 2 strings.

– northenofca
Nov 14 '18 at 5:01

So basically your friendIds list is declared as List<String> friendIds = new ArrayList<>();, right?

– Alex Mamo
Nov 14 '18 at 8:42

No. In this case it is a list of invitations to the friends. It looks like this: List<FriendRequest> requests= new ArrayList<>(); where FriendRequest is an object that contains String frienId and String requestType ("sent" or "received") either he sent invitation or received and this determines which layout to use.

– northenofca
Nov 14 '18 at 9:55

Thanks for your explanation. One more thing, please show me how your friendIds list is declared. Thanks!

– Alex Mamo
Nov 14 '18 at 11:04

add a comment |

in brief: I have a list of users ID and I want to iterate over database and find profiles of those users and put them on the list. But I have a problem as follows:

final List<Friend> friendsProfiles = new ArrayList<>();
 for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);
 // The problem is here, because its called as many times as the size of
 // the friendIds list. loadnewData() contains notifyDataSetChanged()
 mFriendsFragment.loadNewData(friendsProfiles);
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 

 
 );
 
 // It gives 0, because it's called before onDatachange()
 // So I can't call loadNewData() here
 Log.d(TAG, updatedFriendsRequestList.size());

How to do it in the nice, proper way?

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

asked Nov 13 '18 at 16:05

northenofca

135

What is the type of your friendIds list?

– Alex Mamo
Nov 13 '18 at 18:04

I simplified the case in sake of better understanding. In original it contains: String friendId and type of the invitation to friends ("sent" or "received"). So it is basically list of objects that contain 2 strings.

– northenofca
Nov 14 '18 at 5:01

So basically your friendIds list is declared as List<String> friendIds = new ArrayList<>();, right?

– Alex Mamo
Nov 14 '18 at 8:42

No. In this case it is a list of invitations to the friends. It looks like this: List<FriendRequest> requests= new ArrayList<>(); where FriendRequest is an object that contains String frienId and String requestType ("sent" or "received") either he sent invitation or received and this determines which layout to use.

– northenofca
Nov 14 '18 at 9:55

Thanks for your explanation. One more thing, please show me how your friendIds list is declared. Thanks!

– Alex Mamo
Nov 14 '18 at 11:04

add a comment |

in brief: I have a list of users ID and I want to iterate over database and find profiles of those users and put them on the list. But I have a problem as follows:

final List<Friend> friendsProfiles = new ArrayList<>();
 for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);
 // The problem is here, because its called as many times as the size of
 // the friendIds list. loadnewData() contains notifyDataSetChanged()
 mFriendsFragment.loadNewData(friendsProfiles);
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 

 
 );
 
 // It gives 0, because it's called before onDatachange()
 // So I can't call loadNewData() here
 Log.d(TAG, updatedFriendsRequestList.size());

How to do it in the nice, proper way?

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

asked Nov 13 '18 at 16:05

northenofca

135

in brief: I have a list of users ID and I want to iterate over database and find profiles of those users and put them on the list. But I have a problem as follows:

final List<Friend> friendsProfiles = new ArrayList<>();
 for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);
 // The problem is here, because its called as many times as the size of
 // the friendIds list. loadnewData() contains notifyDataSetChanged()
 mFriendsFragment.loadNewData(friendsProfiles);
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 

 
 );
 
 // It gives 0, because it's called before onDatachange()
 // So I can't call loadNewData() here
 Log.d(TAG, updatedFriendsRequestList.size());

How to do it in the nice, proper way?

android firebase firebase-realtime-database android-recyclerview recycler-adapter

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

asked Nov 13 '18 at 16:05

northenofca

135

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

asked Nov 13 '18 at 16:05

northenofca

135

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

edited Nov 13 '18 at 17:56

Frank van Puffelen

236k29382408

asked Nov 13 '18 at 16:05

northenofca

135

asked Nov 13 '18 at 16:05

northenofca

135

asked Nov 13 '18 at 16:05

northenofca

135

What is the type of your friendIds list?

– Alex Mamo
Nov 13 '18 at 18:04

I simplified the case in sake of better understanding. In original it contains: String friendId and type of the invitation to friends ("sent" or "received"). So it is basically list of objects that contain 2 strings.

– northenofca
Nov 14 '18 at 5:01

So basically your friendIds list is declared as List<String> friendIds = new ArrayList<>();, right?

– Alex Mamo
Nov 14 '18 at 8:42

No. In this case it is a list of invitations to the friends. It looks like this: List<FriendRequest> requests= new ArrayList<>(); where FriendRequest is an object that contains String frienId and String requestType ("sent" or "received") either he sent invitation or received and this determines which layout to use.

– northenofca
Nov 14 '18 at 9:55

Thanks for your explanation. One more thing, please show me how your friendIds list is declared. Thanks!

– Alex Mamo
Nov 14 '18 at 11:04

add a comment |

What is the type of your friendIds list?

– Alex Mamo
Nov 13 '18 at 18:04

I simplified the case in sake of better understanding. In original it contains: String friendId and type of the invitation to friends ("sent" or "received"). So it is basically list of objects that contain 2 strings.

– northenofca
Nov 14 '18 at 5:01

So basically your friendIds list is declared as List<String> friendIds = new ArrayList<>();, right?

– Alex Mamo
Nov 14 '18 at 8:42

No. In this case it is a list of invitations to the friends. It looks like this: List<FriendRequest> requests= new ArrayList<>(); where FriendRequest is an object that contains String frienId and String requestType ("sent" or "received") either he sent invitation or received and this determines which layout to use.

– northenofca
Nov 14 '18 at 9:55

Thanks for your explanation. One more thing, please show me how your friendIds list is declared. Thanks!

– Alex Mamo
Nov 14 '18 at 11:04

What is the type of your friendIds list?

– Alex Mamo
Nov 13 '18 at 18:04

I simplified the case in sake of better understanding. In original it contains: String friendId and type of the invitation to friends ("sent" or "received"). So it is basically list of objects that contain 2 strings.

– northenofca
Nov 14 '18 at 5:01

So basically your friendIds list is declared as List<String> friendIds = new ArrayList<>();, right?

– Alex Mamo
Nov 14 '18 at 8:42

No. In this case it is a list of invitations to the friends. It looks like this: List<FriendRequest> requests= new ArrayList<>(); where FriendRequest is an object that contains String frienId and String requestType ("sent" or "received") either he sent invitation or received and this determines which layout to use.

– northenofca
Nov 14 '18 at 9:55

Thanks for your explanation. One more thing, please show me how your friendIds list is declared. Thanks!

– Alex Mamo
Nov 14 '18 at 11:04

add a comment |

1 Answer
1

active

oldest

votes

You can simply count how many you've already loaded, and then call notifyDataSetChanged() only once you've loaded the last one:

final List<Friend> friendsProfiles = new ArrayList<>();
for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);

 if (friendsProfiles.size() == friendIds.length) 
 mFriendsFragment.loadNewData(friendsProfiles);
 
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 
 throw databaseError.toException(); // don't ignore errors, as they break the logic of your app
 
 );

edited Nov 13 '18 at 17:56

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

If the list contains 1000 ids, is it ok to add a listener 1000 times?

– Ioana P.
Nov 13 '18 at 17:23

That seems like a different question. But all your listeners are short-lived, so I doubt it'll create a problem. If it does (or you're worried enough you want to be sure it doesn't), throttle how often you add a next listener: so add the first 10 or so, and then only add the next one once another completes (or gets cancelled).

– Frank van Puffelen
Nov 13 '18 at 17:26

I've got the answer to one of my biggest problems in my today's work from this comment. Thank you!!!! I'll try your solution. +1

– Ioana P.
Nov 13 '18 at 17:33

@IoanaP. I know it's awful solution, but I can not find better one. What do you suggest?

– northenofca
Nov 13 '18 at 17:35

@Frank van Puffelen Thank you, it's simple solution, why it did not come to my mind.. But I will wait, maybe someone post another solution.

– northenofca
Nov 13 '18 at 17:36

|
show 2 more comments

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1 Answer
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1 Answer
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oldest

votes

You can simply count how many you've already loaded, and then call notifyDataSetChanged() only once you've loaded the last one:

final List<Friend> friendsProfiles = new ArrayList<>();
for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);

 if (friendsProfiles.size() == friendIds.length) 
 mFriendsFragment.loadNewData(friendsProfiles);
 
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 
 throw databaseError.toException(); // don't ignore errors, as they break the logic of your app
 
 );

edited Nov 13 '18 at 17:56

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

If the list contains 1000 ids, is it ok to add a listener 1000 times?

– Ioana P.
Nov 13 '18 at 17:23

That seems like a different question. But all your listeners are short-lived, so I doubt it'll create a problem. If it does (or you're worried enough you want to be sure it doesn't), throttle how often you add a next listener: so add the first 10 or so, and then only add the next one once another completes (or gets cancelled).

– Frank van Puffelen
Nov 13 '18 at 17:26

I've got the answer to one of my biggest problems in my today's work from this comment. Thank you!!!! I'll try your solution. +1

– Ioana P.
Nov 13 '18 at 17:33

@IoanaP. I know it's awful solution, but I can not find better one. What do you suggest?

– northenofca
Nov 13 '18 at 17:35

@Frank van Puffelen Thank you, it's simple solution, why it did not come to my mind.. But I will wait, maybe someone post another solution.

– northenofca
Nov 13 '18 at 17:36

|
show 2 more comments

You can simply count how many you've already loaded, and then call notifyDataSetChanged() only once you've loaded the last one:

final List<Friend> friendsProfiles = new ArrayList<>();
for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);

 if (friendsProfiles.size() == friendIds.length) 
 mFriendsFragment.loadNewData(friendsProfiles);
 
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 
 throw databaseError.toException(); // don't ignore errors, as they break the logic of your app
 
 );

edited Nov 13 '18 at 17:56

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

If the list contains 1000 ids, is it ok to add a listener 1000 times?

– Ioana P.
Nov 13 '18 at 17:23

That seems like a different question. But all your listeners are short-lived, so I doubt it'll create a problem. If it does (or you're worried enough you want to be sure it doesn't), throttle how often you add a next listener: so add the first 10 or so, and then only add the next one once another completes (or gets cancelled).

– Frank van Puffelen
Nov 13 '18 at 17:26

I've got the answer to one of my biggest problems in my today's work from this comment. Thank you!!!! I'll try your solution. +1

– Ioana P.
Nov 13 '18 at 17:33

@IoanaP. I know it's awful solution, but I can not find better one. What do you suggest?

– northenofca
Nov 13 '18 at 17:35

@Frank van Puffelen Thank you, it's simple solution, why it did not come to my mind.. But I will wait, maybe someone post another solution.

– northenofca
Nov 13 '18 at 17:36

|
show 2 more comments

You can simply count how many you've already loaded, and then call notifyDataSetChanged() only once you've loaded the last one:

final List<Friend> friendsProfiles = new ArrayList<>();
for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);

 if (friendsProfiles.size() == friendIds.length) 
 mFriendsFragment.loadNewData(friendsProfiles);
 
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 
 throw databaseError.toException(); // don't ignore errors, as they break the logic of your app
 
 );

edited Nov 13 '18 at 17:56

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

You can simply count how many you've already loaded, and then call notifyDataSetChanged() only once you've loaded the last one:

final List<Friend> friendsProfiles = new ArrayList<>();
for (final FriendId friendId : friendIds) 
 mUserRef.child(friendId).addListenerForSingleValueEvent(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 // Get the friend profile
 Friend friend = dataSnapshot.getValue(Friend.class);
 // Add to the list
 friendsProfiles.add(friend);

 if (friendsProfiles.size() == friendIds.length) 
 mFriendsFragment.loadNewData(friendsProfiles);
 
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 
 throw databaseError.toException(); // don't ignore errors, as they break the logic of your app
 
 );

edited Nov 13 '18 at 17:56

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

edited Nov 13 '18 at 17:56

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

answered Nov 13 '18 at 17:22

Frank van Puffelen

236k29382408

If the list contains 1000 ids, is it ok to add a listener 1000 times?

– Ioana P.
Nov 13 '18 at 17:23

That seems like a different question. But all your listeners are short-lived, so I doubt it'll create a problem. If it does (or you're worried enough you want to be sure it doesn't), throttle how often you add a next listener: so add the first 10 or so, and then only add the next one once another completes (or gets cancelled).

– Frank van Puffelen
Nov 13 '18 at 17:26

I've got the answer to one of my biggest problems in my today's work from this comment. Thank you!!!! I'll try your solution. +1

– Ioana P.
Nov 13 '18 at 17:33

@IoanaP. I know it's awful solution, but I can not find better one. What do you suggest?

– northenofca
Nov 13 '18 at 17:35

@Frank van Puffelen Thank you, it's simple solution, why it did not come to my mind.. But I will wait, maybe someone post another solution.

– northenofca
Nov 13 '18 at 17:36

|
show 2 more comments

If the list contains 1000 ids, is it ok to add a listener 1000 times?

– Ioana P.
Nov 13 '18 at 17:23

That seems like a different question. But all your listeners are short-lived, so I doubt it'll create a problem. If it does (or you're worried enough you want to be sure it doesn't), throttle how often you add a next listener: so add the first 10 or so, and then only add the next one once another completes (or gets cancelled).

– Frank van Puffelen
Nov 13 '18 at 17:26

I've got the answer to one of my biggest problems in my today's work from this comment. Thank you!!!! I'll try your solution. +1

– Ioana P.
Nov 13 '18 at 17:33

@IoanaP. I know it's awful solution, but I can not find better one. What do you suggest?

– northenofca
Nov 13 '18 at 17:35

@Frank van Puffelen Thank you, it's simple solution, why it did not come to my mind.. But I will wait, maybe someone post another solution.

– northenofca
Nov 13 '18 at 17:36

If the list contains 1000 ids, is it ok to add a listener 1000 times?

– Ioana P.
Nov 13 '18 at 17:23

That seems like a different question. But all your listeners are short-lived, so I doubt it'll create a problem. If it does (or you're worried enough you want to be sure it doesn't), throttle how often you add a next listener: so add the first 10 or so, and then only add the next one once another completes (or gets cancelled).

– Frank van Puffelen
Nov 13 '18 at 17:26

I've got the answer to one of my biggest problems in my today's work from this comment. Thank you!!!! I'll try your solution. +1

– Ioana P.
Nov 13 '18 at 17:33

@IoanaP. I know it's awful solution, but I can not find better one. What do you suggest?

– northenofca
Nov 13 '18 at 17:35

@Frank van Puffelen Thank you, it's simple solution, why it did not come to my mind.. But I will wait, maybe someone post another solution.

– northenofca
Nov 13 '18 at 17:36

|
show 2 more comments

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