I am having some trouble getting some data from my Parse table/object with a query. I am trying to simply make a query which looks for the current Parse User's objectID in the "sender" column. When that result is returned, I want to extract the receiver's objectID from the "receiver" column associated with the user that I searched for. I keep getting 0 results, even though I know the data is there. Here is my code:
private List<String> potentialRelationQuery() {
mPotentialRelations = new ArrayList<>();
String currentUserId = mCurrentUser.getObjectId();
ParseQuery<ParseObject> query3 = ParseQuery.getQuery("PotentialRelation");
query3.whereEqualTo("sender", currentUserId);
query3.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> parseObjects, ParseException e) {
if (e == null) {
if (parseObjects.size() > 0) {
for (int i = 0; i < parseObjects.size(); i++) {
ParseUser receiver = (ParseUser) parseObjects.get(i).get("receiver");
String receiverId = receiver.getObjectId();
mPotentialRelations.add(receiverId);
}
}
} else {
Log.d("MyApp", "No matching objects returned from request");
}
}
});
return mPotentialRelations;
}
Since findInBackground is an asynchronous call to Parse isn't it possible that mPotentialRelations returns empty because the findInBackground query hasn't yet completed before the potentialRelationQuery method returns? I know I've had issues with this. Since you can't return data from an inner class (i.e. in the done method of FindCallback), writing this kind of query method has never really worked consistently for me.
Related
I'm using parse backend to store and retrieve the datas for my android app, the storing gets done properly but i have problem in retrieving it. I just went through the parse documentation to retrieve the result but what i get is just 0 for all the retrieved values..im suret that the class exists in the parse cloud with valid values but still i get 0 for all the queries.. this is my code to save:
Toast.makeText(getApplicationContext(),"writing to parse",Toast.LENGTH_SHORT).show();
ParseObject dataObject = new ParseObject("Score");
dataObject.put("correct",correctAnswers);
dataObject.put("wrong",wrongAnswers);
dataObject.put("percent", percentage);
dataObject.saveInBackground();
this is how i get back the saved data
ParseQuery<Score> query = ParseQuery.getQuery("Score");
try {
List<Score> scoreList = query.find();
} catch (ParseException e) {
e.printStackTrace();
}
query = ParseQuery.getQuery("Score");
final Activity ctx = this;
query.findInBackground( new FindCallback<Score>() {
#Override public void done(List<Score> scoreList, ParseException e) {
if ( e == null ) {
ParseObject dataObject = ParseObject.create("Score");
int p = dataObject.getInt("correct");
int q = dataObject.getInt("wrong");
int r = dataObject.getInt("percent");
Toast.makeText(ExamRecordActivity.this,String.valueOf(p),Toast.LENGTH_SHORT).show();
Toast.makeText(ExamRecordActivity.this,String.valueOf(q),Toast.LENGTH_SHORT).show();
Toast.makeText(ExamRecordActivity.this,String.valueOf(r),Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(ctx,
"Error updating questions - please make sure you have internet connection",
Toast.LENGTH_LONG).show();
}
}
});
Inside the done method you are creating a new by calling ParseObject dataObject = ParseObject.create("Score"); and then trying to read values from it without putting any in.
I don't know what the structure of your class is but you need to be iterating through List<Score> scoreList in order to get the queried data.
I'm making a small application. trying to retrieve posts inserted, and then I want to retrieve only new inserted posts, and not retrieving all the posts again.
So do you have any idea on how to I can retrieve last items ( Since the list object retrieved)
Here my Query code :
public void getFeed(int limit, int skip){
ParseQuery<ParseObject> query = ParseQuery.getQuery("Feed");
query.setSkip(skip);
query.setLimit(limit);
query.setCachePolicy(ParseQuery.CachePolicy.CACHE_ELSE_NETWORK);
query.findInBackground(new FindCallback<ParseObject>() {
public void done(List<ParseObject> feedList, ParseException e) {
if (e == null) {
for (int i = 0; i < feedList.size(); i++) {
Post p = new Post(feedList.get(i).get("Text").toString());
mAdapter.addItem(p);
}
Log.d("result", "Here is it:" + feedList.size());
mRecyclerView.setAdapter(mAdapter);
} else {
Log.d("Feed", "Error: " + e.getMessage());
}
}
});
}
keep the last time you checked and then use that time to pull anything greater than the last time checked from the createdAt column or updatedAt column (if its possible for someone to update something you are pulling) of the object. then after your query is finished update that time to the current time.
you can store the viewed posts count and next time when retrieving the list set the count as parameter for skip:
query.setSkip(count);
I've built an application that uses Parse. My application allows users to register, login and then post to a parse cloud database.
I have two Parse classes, one called User and one called Posts. User is made up of ObjectId, username and password, and Posts is made up of ObjectId, text and user. Of which user is a pointer to ObjectId within the User class.
I've created a method in my app called getData() which contains a ParseQuery, this queries the Posts class, selects the text field and includes the user field. The query then retrieves the data into a List and then loops through each row of the List, collecting the String from the text field and then adds it into a ListView on the UI using postList.add(textList.get(i).getString("text")); each time the program goes through the loop.Within the loop is another query, which queries the User class, selects the objectId field, I then add a constraint to the query to tell it to only retrieve data where the objectId field is equal to the user field within the Posts class(I think).
ParseQuery<ParseObject> queryUser = ParseQuery.getQuery("User");
queryUser.selectKeys(Arrays.asList("objectId"));
queryUser.whereEqualTo("objectId", textList.get(i).getString("user"));
Next I want to take the collected username data that the query retrieved, put it into a String and display it on screen in a toast. So basically the getData() method should collect all of the strings from the text field and the username of the user that posted it. The problem is that I'm unsure if i'm trying to go about this in the right way. My app throws an error when this piece of code is executed so I'm obviously doing something wrong.
java.lang.IllegalStateException: ParseObject has no data for this key. Call fetchIfNeeded() to get the data.
at com.parse.ParseObject.checkGetAccess(ParseObject.java:3235)
at com.parse.ParseObject.getString(ParseObject.java:2817)
at com.text.parse.MainActivity$3.done(MainActivity.java:186)
Code at line 186 : queryUser.whereEqualTo("objectId", textList.get(i).getString("user"));
My questions are:
1. Am I trying to do this in the right way?
2. Why am I receiving this error?
Code for getData() method:
public void getData() {
final ArrayList<String> postList = new ArrayList<String>();
final ArrayAdapter<String> listAdapter = new ArrayAdapter<String>(this, R.layout.listview_row, postList);
final ParseQuery<ParseObject> queryPosts = ParseQuery.getQuery("Posts");
queryPosts.selectKeys(Arrays.asList("text"));
queryPosts.include("user");
queryPosts.addDescendingOrder("createdAt");
queryPosts.setLimit(20);
queryPosts.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> textList, ParseException e) {
if (e == null) {
//query successful
for (int i = 0; i < textList.size(); i++) {
postList.add(textList.get(i).getString("text"));
ParseQuery<ParseObject> queryUser = ParseQuery.getQuery("User");
queryUser.selectKeys(Arrays.asList("objectId"));
queryUser.whereEqualTo("objectId", textList.get(i).getString("user"));
queryUser.setLimit(20);
queryUser.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> userList, ParseException e) {
if (e == null) {
String s = userList.get(0).getString("username").toString();
Toast.makeText(MainActivity.this, s, Toast.LENGTH_LONG).show();
}
else {
//query error
Toast.makeText(MainActivity.this, "query error: " + e, Toast.LENGTH_LONG).show();
}
}
});
}
lvText.setAdapter(listAdapter);
} else {
//query error
Toast.makeText(MainActivity.this, "query error: " + e, Toast.LENGTH_LONG).show();
}
}
});
}
Sorry for the long question. Any help would be greatly appreciated, thanks.
UPDATE:For anyone stuck with a similar problem, here's how I got it to work:
public void getData() {
final ArrayList<String> postList = new ArrayList<String>();
final ArrayAdapter<String> listAdapter = new ArrayAdapter<String>(this, R.layout.listview_row, postList);
final ParseQuery<ParseObject> queryPosts = ParseQuery.getQuery("Posts");
queryPosts.include("user");
queryPosts.addDescendingOrder("createdAt");
queryPosts.setLimit(20);
queryPosts.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> textList, ParseException e) {
if (e == null) {
//query successful
for (int i = 0; i < textList.size(); i++) {
postList.add(textList.get(i).getString("text"));
ParseObject po1 = textList.get(i);
ParseObject po2 = po1.getParseObject("user");
String username = po2.getString("username");
Toast.makeText(MainActivity.this, username, Toast.LENGTH_SHORT).show();
}
lvText.setAdapter(listAdapter);
} else {
//query error
Toast.makeText(MainActivity.this, "query error: " + e, Toast.LENGTH_LONG).show();
}
}
});
}
You simply include the column in the class you are querying that holds a pointer to another class, that then gives you access to all of the columns of data within the second class.
This method as shown is doing nothing useful:
ParseQuery<ParseObject> queryUser = ParseQuery.getQuery("User");
queryUser.selectKeys(Arrays.asList("objectId"));
queryUser.whereEqualTo("objectId", textList.get(i).getString("user"));
The selectKeys statement is telling it to only return the contents of the objectId column, which you are passing in to the whereEqualTo statement as a parameter... seems silly to run a query to get a value you already have!?. I would not user selectKeys until you think you need to optimise your queries. The only use this query would have is to let you know if the objectId is valid, since the query will return null if it isn't a valid objectId for a User.
I'm hoping that you want to get more information about the user, so if you remove selectKeys then the other columns will be returned.
The fact that fetchIfNeeded is throwing an exception on due to this line:
queryUser.whereEqualTo("objectId", textList.get(i).getString("user"));
That suggests that textList.get(i).getString("user") is not returning an objectId for a user. If that is instead returning a username as suggested by some of your other comments (not sure here), then you need to change that line of code to read:
queryUser.whereEqualTo("username", textList.get(i).getString("user"));
If there are some other questions you have, you'll need to be a bit more precise in your questions as it isn't really clear what you're asking at the moment.
I am using Parse backend for my android app. I need to query the database for a record that has a field with a specific string value. following is the Parse code
strObjectId is a String initialised with a Parse ObjectId as follows
String strObjectId = MyParseObject.getObjectId();
Parse code
ParseQuery<ParseObject> query = ParseQuery.getQuery("MyDataTable");
query.whereEqualTo("code", Code);
query.getFirstInBackground(new GetCallback<ParseObject>()
{
public void done(ParseObject object, ParseException e)
{
if (object == null)
{
return;
}
else
{
ShowToast("Record found!");
}
}
});
The problem is that it works perfectly okay when 'Code' is hardcoded as follows prior to running above query
String Code = "krErZgz9Is";
But it DOES NOT work when Code is assigned Parse ObjectId as follows
String Code = strObjectId;
Obviously the Data Table does have a record with 'code' field with value 'krErZgz9Is'
Your help will be appreciated
Thanks
Have you tried to print out the strObjectId? If your object is not yet saved in Parse, or the object is not loaded from Parse. It will not have an object Id.
Also, have you tried to check the equality with the objectId directly?
query.whereEqualTo("code", MyParseObject.getObjectId());
I've got this working for me
I created an EditText and contained the text I want to find a match in my query. Just try to hide it in the layout if you don't really want to show it.
EditText editText = (EditText) findViewById(R.id.editText);
editText.setText(strObjectId);
ParseQuery<ParseObject> query = ParseQuery.getQuery("MyDataTable");
query.whereEqualTo("code", editText.getText().toString());
query.getFirstInBackground(new GetCallback<ParseObject>()
{
public void done(ParseObject object, ParseException e)
{
if (object == null)
{
return;
}
else
{
ShowToast("Record found!");
}
}
});
I don't get it why removing the getText() function doesn't work so you better keep it this way.
My Class in parse is called "MyClass" and this one has several objects like
| ObjectId | Names | owners | users | (owners is a pointer of another class)
I want to do a query that gives me all of the names in my object "Names" that belong to the owner but, when I do this query i get this:
com.parse.ParseObject#41828fe0
com.parse.ParseObject#41829fdd
com.parse.ParseObject#4182aa28
my code is this
final ParseQuery query = new ParseQuery("MyClass");
query.whereEqualTo("owners", ParseUser.getCurrentUser());
query.findInBackground(new FindCallback() {
public void done( List<ParseObject> MyList, ParseException e) {
if (e == null) {
adapter = new ArrayAdapter<ParseObject>(MyActivity.this, android.R.layout.simple_list_item_1, MyList);
listDev.setAdapter(adapter);
}else{
//error
}
please help me how to do that query that gives me all of name that belong to the owner.
EDIT
I found a solution and is something like this.
ParseQuery<ParseObject> query = ParseQuery.getQuery("MyClass");
ParseUser user = ParseUser.getCurrentUser();
query.whereEqualTo("owners", user);
query.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> objects, com.parse.ParseException e) {
if (e == null) {
for (ParseObject parseObject : objects){
String task;
task= parseObject.get("owners").toString();
adapter.add(task);
adapter.notifyDataSetChanged();
}
} else {
// Something went wrong.
Toast.makeText(getActivity(),"Error: " + e.getMessage().toString(),Toast.LENGTH_SHORT).show();
}
}
});
Your real problem here is your ArrayAdapter. You would need a custom adapter if you want to use Parse objects as your data type. The built in adapter doesn't know how to use Parse objects and is outputting the object as a string for you. Instead you should do something like
arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, MyNamesList);
Where MyNamesList is of type String.
It's hard to help on your query without more information but you are getting Parse objects back, you just need to get the name out of them with something like
MyList.get(i).getString("name");
somewhere outside the query method
private ArrayList<YourObjectType> list;
public void done(List<ParseObject> objects, ParseException e) {
if (objects == null || objects.size() == 0) {
return; //no objects
}
list = new ArrayList<YourObjectType>();
for (int i = 0; i < objects.size(); i++) {
YourObjectType myObject = new YourObjectType();
ParseObject object = objects.get(i);
myObject.objectId = object.getObjectId();
myObject.names = object.get("Names");
myObject.owners = object.get("owners");
myObject.users = object.get("users");
list.add(myObject);
}
adapter = new ArrayAdapter<YourObjectType>(MyActivity.this,android.R.layout.simple_list_item_1, MyList);
listDev.setAdapter(adapter);
}
now set the list to your adapter
your adapter should be able to handle objects of your type, so i think you need to create a custom adapter, the one provided by the android sdk, won't do here
The solution is pretty easy, since you are getting com.parse.whatever, all u need to do is ParseUser user = ParseUser.getCurrentUser();
Then query.whereequalto("owner", user.getUsername());
The problem was, u where querying for currentUser instead of usernames.