Develop Reference

Firebase Database change node ID

How can I change the naming of the nodes of my children in the image below?
questions_stats is a List<Integer>, I'm aware that I get integers as nodes Id because this is a List. I create each of the children randomly with a number between 0 and 1000. I set this ID as part of the object and to find it I loop trough the list. What I want is to set the "0671" as the Key of the Object at the moment I create it.
How should I define my object in order to access each child with an Id that I define as a String.
Each of the questions_stats is an object.
This is my UserProfile Class definition.
public class UserProfile implements Parcelable {
private List<Integer> questions_list;
private List<QuestionsStats> questions_stats;
private String country_name, share_code, user_name;
private int token_count;
private Boolean is_guest;
public UserProfile() {
}
public UserProfile(List<Integer> questions_list, List<QuestionsStats> questions_stats, String country_name, String share_code, String user_name, int token_count, Boolean is_guest) {
this.questions_list = questions_list;
this.questions_stats = questions_stats;
this.country_name = country_name;
this.share_code = share_code;
this.user_name = user_name;
this.token_count = token_count;
this.is_guest = is_guest;
}
}
I know I can set them using the child("0159").setValue(QuestionStats) individually.
But for my purpose I need to retrieve the data of the "user" as a whole and then iterate whithin questions_stats like it is a List.
How should I define my UserProfile class in order to achieve what I want?
Anybody could give me a hint?

How can I change the node names of my children in the image below?
Answer: There is no way in which you can change the names of the nodes from your Firebase database. There is no API for doing that. What can you do instead is to attach a listener on that node and get the dataSnapshot object. Having that data, you can write it in another place using other names. You cannot simply rename them from 0 to 0000, 1 to 0001 and so on.

Perhaps I should have asked for How to "Set" the node Id instead of "Change"
What I have is an List<QuestionsStats>, but when using an List<QuestionsStats> you get indexes as Keys, What I want is to have the same List<QuestionsStats> but instead of indexes, String Keys for each of my items.
So I changed my List for a Map<String, QuestionsStats>. Now the tricky part is when parceling the Object. You can use readMap() or writeMap() to parcel as shown here in this answer by #David Wasser, but it gives a warning:
Please use writeBundle(Bundle) instead. Flattens a Map into the parcel
at the current dataPosition(), growing dataCapacity() if needed. The
Map keys must be String objects. The Map values are written using
writeValue(Object) and must follow the specification there. It is
strongly recommended to use writeBundle(Bundle) instead of this
method, since the Bundle class provides a type-safe API that allows
you to avoid mysterious type errors at the point of marshalling.
So with the help of the comments in This Question I parceled using this code, note that I'm leaving the "easy" way commented in case somebody find it useful or have any comment on that :
protected UserProfile(Parcel in) {
// in.readMap(myMap, Object.class.getClassLoader());
myMap = new HashMap<>();
String[] array = in.createStringArray();
Bundle bundle = in.readBundle(Object.class.getClassLoader());
for (String s : array) {
myMap.put(s, (Object) bundle.getParcelable(s));
}
}
#Override
public void writeToParcel(Parcel dest, int flags) {
// dest.writeMap(myMap);
Bundle bundle = new Bundle();
for (Map.Entry<String, Object> entry : myMap.entrySet()) {
bundle.putParcelable(entry.getKey(), entry.getValue());
}
Set<String> keySet = myMap.keySet();
String[] array = keySet.toArray(new String[keySet.size()]);
dest.writeStringArray(array);
dest.writeBundle(bundle);
}
Why I want this, well at the moment my list contains less than 100 items but it could grow up to a 1000, I'm no Pro, but I believe that if I already know the key of the item I'm interested in will be always better than having to iterate over the list to find it. In the end my main problem was the usage of a Map, I did not know howto.

Iterate through Java jsonObjects without array included

My problem is that this will create 3 new instances of DailyJobObjects with the same values as object number one (01, Bill, 50). And it's logical that it would do so, so how can I iterate through my jsonObject so I can separate the three objects? I have looked this up tirelessly but everything thing I have seen has and array included in the jsonData which would make things easier but this response Body is coming straight from a database - no arrays, just back to back objects. Iterating only gives me keys which I already did in a separate method to give me one half of my map. Now I need the values. You don't have to give me an answer, you can (I rather) point to something I'm missing. Thanks!
{"id":"01","name":"Bill","salary":"50"},
{"id":"02","name":"James","salary":"60"},
{"id":"03","name":"Ethan","salary":"70"}
JSONObject fields = new JSONObject(jsonData);
mObjectArray = new DailyJobObjectArray[fields.length()];
for(int i=0; i< fields.length(); i++) {
DailyJobObject mObject = new DailyJobObject();
mObject.setName(fields.getString("name"));
mObject.setSalary(fields.getString("salary"));
mObjectArray[i] = mObject;
}
return mObjectArray;

As #Selvin has mentioned, your json is not valid. Either get proper json from the database or parse it in a non-standard way. I would suggest getting a proper json array from the DB.
String[] splitString = jsondata.split("[^a-zA-Z \\{\\}]+(?![^\\{]*\\})");
for ( String s : splitString) {
try {
JSONObject field = new JSONObject(s);
String name = field.getString("name");
String id = field.getString("id");
} catch (JSONException e) {
e.printStackTrace();
}
}
I also agree that your mObject(...) does not make sense at all
Maybe you're looking for something like this
mObject.setName(name)

Android JSONObject getString method check for null/NULL?

Hitting a brick wall in my code at the moment for fetching json objects from multiple pages(using a loop) in a AsyncTask. It reaches the last page, but getting the correct if statement to ensure that the loop DOESN'T run again and continues on is baffling me.
String data = //some correct json data with next element that holds a uri parseable string
JSONObject initial = new JSONObject(data);
String next = initial.getString(nextObjSTR);
//gonna start from the "last" page and recursively return to the 1st page
if(*The if condition I need help with*) {
//there is another page
makeConnection(Uri.parse(next));
}
Basically, the last page of json elements has a next element with a null or no element value, which triggers the IOException error caught in makeConnection method because my initial if statement has always been failing.
Can I get a reason or help as to the appropriate if check for Strings from json? I've tried String != null as NullPointerExceptions occur if I use any method from String to compare. Likewise, JsonObject.NULL comparison doesn't work for me either.

None of the other answers worked, and I ended up questioning whether the element was really null despite looking at the parsed json data via an online tool. In the end, JSONObject.IsNull(element mapping name) is the right approach.

If you're sure that the value is either null (empty) or a correct URI, and assuming that the nextObjSTR key is always present in the data JSON, then that will do:
if (next != null && !next.trim().isEmpty()) {
makeConnection(Uri.parse(next));
}
Or, since you're on Android, it's better use the more convenient method:
if (!TextUtils.isEmpty(next)) {
makeConnection(Uri.parse(next));
}

You can use the optString Method of the JSONObject. If the JSON key is not this method will return a empty string, so you can check it easily:
String next = initial.optString(nextObjSTR);
if ( ! next.isEmpty() ) {
makeConnection(Uri.parse(next));
}
Source: https://developer.android.com/reference/org/json/JSONObject.html#optString(java.lang.String)

you must check value with key is has in json object.
Try below code:
JSONObject initial = new JSONObject(data);
if(initial.has(nextObjSTR)) {
String next = initial.getString(nextObjSTR);
if (next != null && !next.isEmpty()) {
makeConnection(Uri.parse(next));
}
}

I do like this...
String value;
if(jsonObject.get("name").toString.equals("null")){
value = "";
else{
value = jsonObject.getString("name");
}

How is this JSON string supposed to be parsed to get the different fields

I have this JSON string that I am recieving after I make a purchase from the playstore and I am apparently missing something in my code when I am trying to parse it.
PurchaseInfo:{"orderId":"12999763165555505758.1317333586444405",
"packageName":"com.mypkgname.myapp",
"productId":"monthly_purchase_01",
"purchaseTime":1357456489000,
"purchaseState":0,
"purchaseToken":"yrynypfkdncvhlxdbypysvwz.AO-J1OxFkndfqkClAqbbYAOApkMgTG4VX9Ef0uNP0FIs9-xGrXivkbx3FNMA2yNU12K_sbvRGFcknVBTfisI-uZawCXLGlMX4v4Zw8GFOmS0Q6PIbiITTGqn5h1QbEB4Rv84sXdUJHP3B_UQfujZN7ADi9bm_N4_iA"}
Here is the snippet of code I am using it to attempt the parsing
try {
JSONObject j1 = new JSONObject(tester1);
JSONArray mPurchInfo = j1.getJSONArray("PurchaseInfo");
int count = mPurchInfo.length();
final String[] purchInfo = new String[count];
JSONObject q1 = mPurchInfo.getJSONObject(0);
purchInfo[0] = q1.getString("orderId");
purchInfo[1] = q1.getString("packageName");
purchInfo[2] = q1.getString("productId");
purchInfo[3] = q1.getString("purchaseTime");
purchInfo[4] = q1.getString("purchaseState");
purchInfo[5] = q1.getString("purchaseToken");
orderID=purchInfo[0];
} catch (JSONException e) {
Log.e("Error","Yes");
}
I am catching the an error as I see this last log statement in my log but I am still trying to learn the parsing JSON Strings
I hope I am at least close
Ideally I would like to have Strings set to all the values in the JSON String
orderID = ??
packageName = ??
etc.
Thanks

I have this JSON string that I am recieving after I make a purchase from the playstore
If that's really what you get back, you need to contact them and tell them to fix their API; that string is not valid JSON. There are two problems with it:
A JSON document must have an object or array as the top-level item. The string as quoted is missing a { at the beginning and a } at the end.
All keys in JSON must be in double quotes. The first one, PurchaseInfo, is not.
Also, your code is doing this:
JSONArray mPurchInfo = j1.getJSONArray("PurchaseInfo");
...but if it were valid JSON, PurchaseInfo wouldn't be an array, it'd be an object.
Looking at it, if you remove the PurchaseInfo: at the beginning, it's valid. Once you've removed that, this line:
JSONObject j1 = new JSONObject(tester1);
...will give you an object from which you can query information:
String orderId = j1.getString("orderId");

Alphabet Indexed ListView Without a cursor

I receive data from a server using JSON and I want to order them alphabetically with alphabet indexed section and store them in a ListView.
Maybe something that will happen in :
for(int i=0;i<jArray.length();i++){
// here
}
I read that you can order elements like that only using a cursor. In my case would be very inefficient to store the elements from the server in the database and read them again. Waste of time and memory.
So, I am asking you if there could be any solution for my problem : order alphabetically with alphabet indexed section string received from JSON .
EDIT: I want my listview to look like this http://eshyu.wordpress.com/2010/08/15/cursoradapter-with-alphabet-indexed-section-headers/ . I mean with those sections . All tutorials I found said that you need to fetch information with a cursor. My question was if I could't do this wihout a cursor, because it would be a waste of memory to store them in the local database too.

You may need to parse the JSON Array :
List<Project> list = new ArrayList<Project>();
for (int i = 0; i < jArray.length(); i++) {
JSONObject obj = (JSONObject) jArray.get(i);
project = new Project();
project.setId( Long.parseLong(obj.get("id").toString()));
project.setKey(obj.get("key").toString());
project.setName(obj.get("name").toString());
list.add(project);
}
You can use the comparator class like this to sort them :
Collections.sort(list), new Comparator<Project>() {
public int compare(Project p1, Project p2) {
return p1.getKey().compareToIgnoreCase(p2.getKey());
}
});
You can also have Project class and implements Comparable:
public class Project implements Comparable<Project> {
private long id;
private String key;
private String name;
public int compareTo(Project p) {
if (this.key > p.key)
return -1;
else if (this.key < p.key)
return 1;
return 0;
}
}
And then sort the list by Collections.sort(list);
My suggestion is try to sort the data in the Server-side, because the memory of the phone is limited and it may make you application time consuming to show the data, but you do not have memory limitation problem in the Server-side.

use a comparator to sort the arraylist as described here . And then use an ArrayAdapter to show the items in Listview