Collect all data from FirebaseDatabse and call notifyDataSetChanged() once












1















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?










share|improve this question

























  • 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
















1















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?










share|improve this question

























  • 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














1












1








1








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?










share|improve this question
















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






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 13 '18 at 17:56









Frank van Puffelen

232k29380406




232k29380406










asked Nov 13 '18 at 16:05









northenofcanorthenofca

135




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



















  • 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







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





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





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





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





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












1 Answer
1






active

oldest

votes


















3














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
}
});
}





share|improve this answer


























  • 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











Your Answer






StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53284983%2fcollect-all-data-from-firebasedatabse-and-call-notifydatasetchanged-once%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









3














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
}
});
}





share|improve this answer


























  • 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
















3














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
}
});
}





share|improve this answer


























  • 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














3












3








3







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
}
});
}





share|improve this answer















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
}
});
}






share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 13 '18 at 17:56

























answered Nov 13 '18 at 17:22









Frank van PuffelenFrank van Puffelen

232k29380406




232k29380406













  • 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

















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

– Ioana P.
Nov 13 '18 at 17:23





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





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







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





@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





@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


















draft saved

draft discarded




















































Thanks for contributing an answer to Stack Overflow!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53284983%2fcollect-all-data-from-firebasedatabse-and-call-notifydatasetchanged-once%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Florida Star v. B. J. F.

Danny Elfman

Lugert, Oklahoma