Develop Reference

Unable to retrieve relational data with object id

I am trying to retrieve a list of posts (_Relation ) that are stored as a relation in a parse class called "Threads". I tried many different usages but didn't succeed though the object Id and the getClassName methods are working I am unable to get the list.
ParseRelation<ParseObject> posts = recylerViewListAdapter.currentThreadObject.threadObject.getRelation("postMessage");
ParseQuery postsQuery = posts.getQuery();
Log.d("DEBUG_NETWORK_CALL : ", String.valueOf(postsQuery.getClassName())); // This works and I get the class name as "Posts" while debugging.
// The List size retrieved is 0 when I print it
postsQuery.findInBackground(new FindCallback() {
#Override
public void done(List list, ParseException e) {
List<postModelStore> postModelStoreArrayList = new ArrayList<postModelStore>();
Log.d("DEBUG_NETWORK_RETRIEVAL : ","DONE");
Log.d("DEBUG_NETWORK_LIST_SIZE : ",String.valueOf(list.size()));
for (int i = 0; i < list.size(); i++) {
ParseObject parseObject = (ParseObject) list.get(i);
String postMessage = (String) parseObject.get("postMessage");
Log.d("post Message", postMessage);
ParseUser parseUser = (ParseUser) parseObject.get("postedBy");
String profilePictureUrl = "local";
profilePictureUrl = ((ParseFile) parseUser.get("profilePicture")).getUrl();
postModelStore retrievedPostDetails = new postModelStore(postMessage, profilePictureUrl);
postModelStoreArrayList.add(retrievedPostDetails);
}
postListObject = postModelStoreArrayList;
}
#Override
public void done(Object o, Throwable throwable) {
callMe();
}
});

Parse - Android - Will an exception be caused if no data is returned on a Parse query?

A quick question - would an exception be caused on a Parse query if no matches were found and no data was returned by the query? For example, I'm looking to query my username table to find out if a user/username already exists or not. So I'm wondering if no matches were found on a username then would that return an unsuccesful query with an exception or a successful query with no data in the list of objects?
ParseQuery<ParseUser> userQuery = ParseUser.getQuery();
query.whereEqualTo("username", usernameInput);
query.findInBackground(new FindCallback<ParseUser>() {
#Override
public void done(List<ParseUser> objects, ParseException e) {
//query was successful
if (e == null) {
}
//query was unsuccessful
else {
}
}

If you follow the code from ParseQuery:
public Task<List<T>> findInBackground() {
return findAsync(builder.build());
}
you’ll eventually stumble upon this:
// Converts the JSONArray that represents the results of a find command to an
// ArrayList<ParseObject>.
/* package */ <T extends ParseObject> List<T> convertFindResponse(ParseQuery.State<T> state,
JSONObject response) throws JSONException {
ArrayList<T> answer = new ArrayList<>();
JSONArray results = response.getJSONArray("results");
if (results == null) {
PLog.d(TAG, "null results in find response");
} else {
String resultClassName = response.optString("className", null);
if (resultClassName == null) {
resultClassName = state.className();
}
for (int i = 0; i < results.length(); ++i) {
JSONObject data = results.getJSONObject(i);
T object = ParseObject.fromJSON(data, resultClassName, state.selectedKeys() == null);
answer.add(object);
/*
* If there was a $relatedTo constraint on the query, then add any results to the list of
* known objects in the relation for offline caching
*/
ParseQuery.RelationConstraint relation =
(ParseQuery.RelationConstraint) state.constraints().get("$relatedTo");
if (relation != null) {
relation.getRelation().addKnownObject(object);
}
}
}
return answer;
}
Inspect the above - you can see that a successful query, even though it might contain no data, will still return a non-null ArrayList instance.

How to run code sequentially with parse, in Android?

I am trying to get records from parse. My table in parse contains an array of pointers; I was facing difficulties to write parse query, so I first save array of pointers in an ArrayList, now I make a for loop to execute the query; for each loop iteration, I want to get records from parse and update local db then same as for next iterations. But this is creating some different problems. parse getInBackground is not working sequentially.... my outer for loop completely executes then parse method called due to which I am facing problems to save values in local db.
public void insertGroupsInDB(ArrayList<TempGroupClass> temp)
{
Log.d(TAG,"insertGroupsInDB: temp size:"+temp.size());
for(int i = 0;i<temp.size();i++) `//my target is to make inner query run till no of loop times and for each iterations inner parse query will run and then insert records in db against outer insertion group`
{
Groups grp = new Groups();
grp.setGroupTitle(temp.get(i).getGroupTitle());
grp.setGroupType(temp.get(i).getGroupType());
grp.setParseObjectId(temp.get(i).getParseObjectId());
long groupinsert = (YouinDatabase.getInstance(context)).addGroup(grp,context);
//}
/*try
{
final CountDownLatch latch = new CountDownLatch(1);*/
if(groupinsert != -1)
{
//now insert friends
//long friendInsertId = YouinDatabase.getInstance(context).addFriend();
//now get friends from members id
Log.d(TAG,"groups inserted successfully:"+groupinsert);
final ArrayList<Integer> list = new ArrayList<Integer>();
if(temp.get(i).getFriendObjectIdList().size() > 0)
{
for(int j =0;j<temp.get(i).getFriendObjectIdList().size();j++)
{
Log.d(TAG," >>>>>>>>>>>>>>>friend objectId>>>>>>>>>>>>>>:"+temp.get(i).getFriendObjectIdList().get(j));
ParseQuery<ParseUser> query = ParseUser.getQuery();
query.whereContainedIn("objectId",temp.get(i).getFriendObjectIdList());
query.findInBackground(new FindCallback<ParseUser>() {
#Override
public void done(List<ParseUser> arg0,
ParseException arg1) {
// TODO Auto-generated method stub
if(arg1 == null)
{
//Log.d(TAG,"arg0 size:"+arg0.size());
if(arg0.size() >0)
{
for(int i = 0;i<arg0.size();i++)
{
Log.d(TAG,"arg0.size():"+arg0.size());
Friend f = new Friend();
f.setUsername(arg0.get(0).getString("username"));
f.setParseObjectId(arg0.get(0).getObjectId());
f.setHasAdded(false);
boolean userAlreadyExist = YouinDatabase.getInstance(context).checkUserExistInFriendTable(arg0.get(0).getString("username"));
long friendInsertId = -1;
ArrayList<Integer> list = new ArrayList<Integer>();
int friendid;
if(!userAlreadyExist)
{
// Log.d(TAG,"friend Already not exist :"+userAlreadyExist);
friendInsertId = YouinDatabase.getInstance(context).addFriend(f);
list.add(YouinDatabase.getInstance(context).findFriendIdOfLatestRecord());
friendid = YouinDatabase.getInstance(context).findFriendIdOfLatestRecord();
}
else
{
//Log.d(TAG,"friend Already exist :"+userAlreadyExist);
//list.add(YouinDatabase.getInstance(context).getFriendIdFromFriendName(arg0.get(0).getString("username")));
friendid = YouinDatabase.getInstance(context).getFriendIdFromFriendName(arg0.get(0).getString("username"));
}
// Log.d(TAG,"list size 1 :"+list.size());
int latestGroupInsertId = YouinDatabase.getInstance(context).findGroupIdOfLatestRecord();
long id = YouinDatabase.getInstance(context).addFriendInConnection(friendid,latestGroupInsertId);
//now update user setHasAdded
long updateFriendTable = -1;
if(id != -1)
{
updateFriendTable = YouinDatabase.getInstance(context).updateFriendTable(friendid);
}
Log.d(TAG,">>>>updated friend id information:>>>>");
if(updateFriendTable != -1)
{
Friend friendDetails = YouinDatabase.getInstance(context).getFriendDetailsFromFriendId(friendid);
Log.d(TAG,"friend name:"+friendDetails.getUsername());
Log.d(TAG,"friend:"+friendDetails.getParseObjectId());
Log.d(TAG,"friend added :"+friendDetails.isHasAdded());
Log.d(TAG,"groupId:"+latestGroupInsertId);
}
//YouinDatabase.getInstance(context).get
}
Log.d(TAG,"list size 2"+list.size());
}
}
else
{
Log.d(TAG,"arg1 != null:"+arg1.getMessage());
}
}
});
}
// Log.d(TAG,"list size:"+list.size());
}
//latch.countDown();
}
/*latch.await();
}
catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
*/
}
Right now, the problem is that my outer loop executes twice one after another and then after the loop ends, then my parse method brings data from parse ...due to which it's only updating record in db against last group id ...and it's not inserting records against first groupId
How to resolve this issue? I have used this technique because I failed to write query to get object result of array of pointers using parse.

You could use find() which should do a synchronous operation which might hold up your ui. I have not used parse yet so i dont know. Or you can set up something like below. Remove the outer and check conditions in your callback to determine when to launch the next query.
private int j = 0;
private int loopnumber = temp.size();
ArrayList<TempGroupClass> temp; //setup temp somewhere else
private void doQuery() {
ParseQuery<ParseUser> query = ParseUser.getQuery();
query.whereContainedIn("objectId",temp.get(i).getFriendObjectIdList());
query.findInBackground(new FindCallback<ParseUser>() {
#Override
public void done(List<ParseUser> arg0,
ParseException arg1) {
// TODO Auto-generated method stub
if(arg1 == null)
{
...
...
else
{
Log.d(TAG,"arg1 != null:"+arg1.getMessage());
}
//at the end call the same method to start a query if the loop conditions have not been reached.
if(++i < loopnumber) {
doQuery();
}
}
});
}
}

Calling a parse function asynchronously

I have to fetch some data from the parse cloud. I'm using the parse sdk for android. How do I call the method findInBackground asynchronously in my activity? Essentially, where do I place this piece of code in my Activity? Below is my code:
ParseQuery<ParseObject> query = ParseQuery.getQuery("Average");
query.whereEqualTo("squarefeet", area);
query.findInBackground(new FindCallback<ParseObject>() {
public void done(List<ParseObject> objects, ParseException e) {
if (e == null) {
if (objects.size() > 0) {
for (int i = 0; i < objects.size(); i++) {
ParseObject p = objects.get(i);
averageConsumption = p
.getNumber("average_consumption");
efficientConsumption = p
.getNumber("efficient_consumption");
}
}
} else {
// something went wrong!
}
}
});

I called it inside an OnClick method of an OnClickListener. This made it asynchronous! Pretty silly but works! Previously I called it synchronously in OnCreate.

getting all the records from table -Parse.com

i have around 13000 records on one table(HashTag -classname) . i want to retrieve all of them on a single query. but parse allows only 1000 per query. any other ways get the all the records..
ParseQuery<ParseObject> query = ParseQuery.getQuery("HashTag");
query.whereExists("Tag"); query.orderByAscending("Type"); query.setLimit(1000);
query.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> list,
ParseException e) {
// TODO Auto-generated method stub
if (e == null)
{
if (list.size() > 0) {
for (int i = 0; i < list.size(); i++) {
ParseObject p = list.get(i);
String tagid = p.getString("Tag");
String Type = p.getString("Type");
class2 c2 = new class2();
c2.type = "" + Type;
c2.tag = "" + tagid;
listClass2.add(c2);
}
}

Sure, you can run multiple queries on the same table, with query's skip property incremented by 1000 each time:
Get the total number of records via query.count(), and use it to set a 'skip' variable
Run a new query for each 1000 records, updating your skip property accordingly
Process records as normal when each query returns
Something like this:
ParseQuery<ParseObject> query = ParseQuery.getQuery("HashTag");
query.whereExists("Tag");
query.countInBackground(new CountCallback() {
public void done(int count, ParseException e) {
if (e == null) {
// The count request succeeded. Run the query multiple times using the query count
int numQueries = Math.ceil(count / 1000); //Gives you how many queries to run
for(int skipNum = 0; l < numQueries; l++){
ParseQuery<ParseObject> query = ParseQuery.getQuery("HashTag");
query.whereExists("Tag"); query.orderByAscending("Type");
query.setLimit(skipNum * 1000);
query.findInBackground(new FindCallback<ParseObject>() {
//Run your query as normal here
}
}
} else {
// The request failed
}
}

//Declare a global variable for storing the complete data
private static List<ParseObject>allObjects;
allObjects=new ArrayList<ParseObject>();
ParseQuery<ParseObject>query3=ParseQuery.getQuery("HashTag");
query3.whereExists("Tag");
query3.setLimit(1000);
query3.findInBackground(getallobjects());
int limit=1000;
int skip=0;
//callback method:
private FindCallback<ParseObject>getallobjects(){
return new FindCallback<ParseObject>(){
#Override
public void done(List<ParseObject>list,ParseException e){
allObjects.addAll(list);
if(list.size()==limit){
skip=skip+limit;
ParseQuery<ParseObject>query=ParseQuery.getQuery("HashTag");
query.setSkip(skip);
query.setLimit(limit);
query.findInBackground(getallobjects());
}else{
//you have full data in allobjects
for(int i=0;i<allObjects.size();i++){}
}
}}}

ParseQuery<ParseObject> query = new ParseQuery<ParseObject>("TestObject");
query.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> list, ParseException e) {
for(ParseObject p : list){
Log.d("--", (String) p.get("foo")+p.getCreatedAt());
}
}
});