I am trying to make some kind of comments using Firebase for Android.
Just have one question, are there any way to add new items to array?
For example, if I have such kind of object
If I am trying to push, it will convert it to map
And I don't want to overwrite this object each time, because I will have multiuser support and it will fail at some point.
And I am trying to do it as a List to do not create DataTransferObjects for my models, and to support auto parsing using firebase.
Thanks! If there will be no ideas will go with creating Maps, actually.
My ObjectModel:
public class Company implements Parcelable {
private String id;
private String name;
private String description;
private List<Comment> comments;
}
Code for pushing item:
final DatabaseReference ref = companiesRef.child(companyId).child(NODE_COMMENTS).push();
return Single.create(e -> ref.setValue(comment)
.addOnCompleteListener(task -> {
e.onSuccess(task.isSuccessful());
}));
This is how it works, look at the example below I have stored "0" as my first commentID and "1" as my second commentID. As you can see, I stored the lastCommentID as the commentID for the last comment in the lists.
{
"comments": {
"0": {
"text": "mycomment",
"time": "142351516"
},
"1": {
"text": "secondcomment",
"time": "153426564"
}
}
"lastCommentId": "1"
}
So whenever you want to add new comment to the firebase you have to retrieve the lastCommentID first as a string and convert it to integer(E.g. 1) then add 1 to the value(E.g. 2) so that when you save the next comment it won't override the previous version.
Note that you have replace lastCommentID each time you add comment to the database.
{
"comments": {
"0": {
"text": "mycomment",
"time": "142351516"
},
"1": {
"text": "secondcomment",
"time": "153426564"
},
"2": {
"text": "thirdcomment",
"time": "153426564"
}
}
"lastCommentId": "2"
}
You do not need to have a Model Class to write in Firebase, you can parse a JSON to Java Objects dinamically with Jackson and push it into Firebase.
You can parse a JSON as Java Objects with Jackson
. For example you can obtain: Object, List, Hashmap, Integer, String,
etc. without POJO classes.
To see more please visit this answer
Related
I'm very new to NoSql databases, and I just want to ask you an easy question about the use of sembast! I'm developing a very simple app with flutter, and I want to get the object inside the array "list" with the "name" equal to 1.
{
"id": 12345,
"list": [{
"name": 1,
"element": [{
"nameItem": "a"
}, {
"nameItem": "b"
}]
}, {
"name": 2,
"element": []
}, {
"name": 3,
"element": []
}]
}
So I want to make a query that retrieves me this information:
{
"name": 1,
"element": [{
"nameItem": "a"
}, {
"nameItem": "b"
}]
}
I've written this code, but it doesn't work: I don't understand how to make a query with a subtag as a key in the json tree.
Future<List<ElementList>> getElementFromList(int name) async{
final finder = Finder(filter: Filter.equals("name", name));
final recordSnapshot = await _elementList.find(await _db, finder: finder);
return recordSnapshot.map((snapshot){
final elementObj = ElementList.fromJson(snapshot.value);
return elementObj;
}).toList();
}
this returns me []. How can I solve the problem?
Thank you in advance!
Sembast queries allow to filter records, not part of a record. If the object you mention is a whole record, you can:
use custom filter to perform the lookup yourself for each record in the database (checking each item in the list field`)
when a record is retrieved, extract the item (doing a similar Map/List manipulation)
See an issue with a complex filtering
This is my JSON
[{
"user_name": "name",
"tags": ["p", "a", "py"],
"a": 3,
"b": 12,
"c": 4
},
{
"user_name": "name2",
"tags": ["p2", "a2", "py2"],
"a": 32,
"b": 122,
"c": 42
}]
I have no problems using retrofit to get all the other values, except tags. How do I do it?
If you provide some code of what you are actually using currently that would help us help you better. In any case since you mentioned you are doing these already I am assuming you have created the POJO class for this response with something like
public class YourResponse
{
private String a;
private String b;
private String c;
private String user_name;
private String[] tags;
....
}
Now when you write a call to the api, since its a list of this class' objects you should write as
Call<List<YourResponse>> call = ...
and similarly in callbacks etc. like call.enqueue(new Callback<List<YourResponse>>()......
Edit: Just noticed you mentioned your problem was only with getting the values for "tags" and not the response. Your question is already answered by #Mark Keen in his comment. -"tags should be a List<String>, or String[]"
I have a json in which 1 key is coming as jsonArray if it has data otherwise it is coming as empty string. It is giving error while parsing in gson with retrofit.
"section": "Technology",
"subsection": "",
"title": "Depiction of Amazon Stirs a Debate About Work Culture",
"abstract": "Details of working conditions at Amazon led to a response from employees, relatives and friends.",
"url": "http://www.nytimes.com/2015/08/19/technology/amazon-workplace-reactions-comments.html",
"byline": "By THE NEW YORK TIMES",
"item_type": "Article",
"updated_date": "2015-08-18T07:35:33-5:00",
"created_date": "2015-08-18T07:35:35-5:00",
"published_date": "2015-08-19T04:00:00-5:00",
"material_type_facet": "News",
"kicker": "",
"des_facet": [
"Workplace Environment"
],
"org_facet": [
"Amazon.com Inc"
],
"per_facet": "",
"geo_facet": "",
des_facet , org_facet, per_facet, geo_facet are jsonArray but you can see that 2 are not having data so coming as empty string.
How to handle this scenario with retrofit +gson.
Json format can't be changed here at server.
is there any way I can achieve it in android?
Ok so there are two option you can solve this
Option 1:
JSON which I used as a example
"des_facet": [
"Workplace Environment"
],
"org_facet": [
"Amazon.com Inc"
],
"per_facet": ["Akshay"],
"geo_facet": ""
In your model class convert those variable to Object type
#Expose
#SerializedName("geo_facet")
private Object geo_facet;
#Expose
#SerializedName("per_facet")
private Object per_facet;
then where you want to set data do the following
if (model != null)
{
if (model.getGeo_facet() != null || model.getGeo_facet() != "")
{
Object arr = model.getGeo_facet();
}
if (model.getPer_facet() !=null || model.getPer_facet()!= "")
{
Object arr = model.getPer_facet();
if (arr!=null && arr.toString().length()>0)
{
arr = arr.toString();
Log.d("akshay","arr= "+arr);
//Do your Stuff or Set data
}
}
}
This is the output= 08-11 16:51:29.830 17951-17951/com.android.example
D/akshay: arr= [Akshay]
Option 2:
Follow this which is a little bit complex
Option 3:
Write own custom Parsing like this and Handle your response accordingly
a json can have a single structure. From the code it is clear that the key is given with 2 types of data
Ideally, it should not give "" when no items. It should give null
Please change the data
If no items,
"des_facet"=null // this is the change on server side. No need to change it on app side
If it has items
"des_facet"=[
"Workplace Environment"
]
instead of
If no items,
"des_facet"=""
If it has items
"des_facet"=[
"Workplace Environment"
]
You can use AutoValue with gson plugin and mark the field as nullable which will notify the Autovalue to make this field optional.
AZs an example this is how you do it:
#AutoValue
public abstract class NewsResponse{
public static TypeAdapter<NewsResponse> typeAdapter(Gson gson){
return new AutoValue_NewsResponse.GsonTypeAdapter(gson);
}
#SerializedName("api_status")
public abstract String apiStatus();
#SerializedName("api_text")
public abstract String success();
#Nullable
#SerializedName("errors")
public abstract ErrorDetails errorDetails();
#SerializedName("news")
public abstract List<NewsDetails> newsDetails();
}
you must import both of them see more info about importing at: AutoValue and AutoValue Gson Plugin
I am not that skilled with Retrofit library and I ran into a problem that i don't know how to handle without restructuring the whole project.
Basically, i have two responses that are very similar, but my code only handles one response.
Here are the responses and what i did, so tell me if there is any way to do this...
{
"cv":[
{
"id":46,
"name":"Ciriculum Vitae",
"description":"Lorem ipsum description is the best description one can write down",
"file":"1482915089-test-test-cv1.pdf",
"file_url":"http://xxxyy/file/46/1482915089-test-test-cv1.pdf",
"type":"cv"
},
...
],
"diploma":[
{
"id":52,
"name":"dasdasdasdsa",
"description":"Random description",
"institution_name":"hello",
"completed_date":"12.12.2016.",
"file":"1482918005-test-test-dasdasdasdsa.pdf",
"file_url":"http://xxxyy/file/52/1482918005-test-test-dasdasdasdsa.pdf",
"type":"diploma"
}
],
...
"certification":[
{
"id":50,
"name":"Certificate of Greatness",
"description":"I have been great at many things so everybody diecided to give me a certificate for it.",
"institution_name":"Certification 3",
"validation_date":"10.06.2017.",
"file":"1482917772-test-test-dasdasdasdsa.pdf",
"file_url":"http://xxxyy/file/50/1482917772-test-test-dasdasdasdsa.pdf",
"type":"certification"
}
],
...
}
Okay this is just a sample, but you can clearly see that these are some documents that have their types. There are 17 types of documents each with different fields.
Logically, I've created 17 different models cv model, diploma model, etc...
The problem arises later in the project when i want to fetch documents that are related to a single candidate, the response then is like so:
Response2
"documents": [
{
"id": 46,
"name": "Ciriculum Vitae",
"type": "cv",
"description": "Lorem ipsum description is the best description one can write down",
"file": "1482915089-test-test-cv1.pdf",
"file_url": "http://xxxyy/file/46/1482915089-test-test-cv1.pdf"
},
{
"id":52,
"name":"dasdasdasdsa",
"description":"Random description",
"institution_name":"hello",
"completed_date":"12.12.2016.",
"file":"1482918005-test-test-dasdasdasdsa.pdf",
"file_url":"http://xxxyy/file/52/1482918005-test-test-dasdasdasdsa.pdf",
"type":"diploma"
},
{
"id": 50,
"name": "Certificate of Greatness",
"type": "certification",
"description": "I have been great at many things so everybody diecided to give me a certificate for it.",
"file": "1482917772-test-test-dasdasdasdsa.pdf",
"file_url": "http://xxxyy/file/50/1482917772-test-test-dasdasdasdsa.pdf"
}
]
}
Now obviously the field 'type' is the type of object that needs to be created. But so far i don't know how to make my models fit into this 2nd response.
What should i do here, guys?
In case you're wondering what my code looks like, here it is...
#SerializedName("cv")
#Expose
private List<Cv> cv = null;
...
#SerializedName("diploma")
#Expose
private List<Diploma> diploma = null;
...
#SerializedName("certification")
#Expose
private List<Certification> certification = null;
EDIT
Actually what i wanted to do is create object dependent on the 'type' parameter and fill it with info i get from the response.
How will i go about doing this?
I found a lot of tutorials here, how to parse JSON Data of an JSON Array.
But my JSON File is a little bit complicate (for me). It has the following structure:
JSON File (excerpt)
{
"data": {
"schedule_id": {
"12": {
"name": "CP",
"d_id": [
"7"
]
},
"17": {
"name": "WT",
"d_id": [
"88",
"14"
]
}
}
}
}
Java Code (excerpt)
Info: I've parsed the json into "json" using HTTP GET in another Activity.
JSONObject dataJsonData = json.getJSONObject("data").getJSONObject("schedule_id");
Now I would parse through the ids using a "for"-loop:
ArrayList<String> parsedNameList = new ArrayList<String>();
for (int i = 0; i < idontknow; i++) {
String s = new Integer(i).toString();
parsedNameList.add(dateJsonData.getJSONObject(i).getString("name"));
}
This would add each value of "name" to the ArrayList.
But there are 2 problems:
1. The "schedule_id"s are messed up and incomplete. For example, there is no id "0" and, like in given json, the ids "13, 14, 15, 16" are missing.
2. The "schedule_id"s will be changed every day and will be mixed.
So I don't think, that I can use the predefined integer "i" because some integers aren't a "schedule_id". I could use this loop and would ignore empty entries in the ArrayList, but the JSON contains more than 200 ids - I think it would be more efficient, if there is another way to parse through this json.
I found some informations of the getJSONArray method, but the "d_id"s are Arrays - not the "schedule_ids".
Does anyone has an idea? Is there maybe a placeholder for the parameter of the getString method?
PS: Excuse my english, I'm from germany :)
I think this should work
Iterator keys = dataJsonData.keys();
while(keys.hasNext()) {
// loop to get the dynamic key
String currentDynamicKey = (String)keys.next();
// get the value of the dynamic key
String currentDynamicValue = dataJsonData .getString(currentDynamicKey);
parsedJsonList.add(currentDynamicValue );
}
Source: How to parse a dynamic JSON key in a Nested JSON result?
According to your context, it is better to change the json structure,if you have access to web service.
Request for json structure to be like this,
{
"data":{
"schedule":[
{
"id":12,
"name":"CP",
"d_id":[
"7"
]
},
{
"id":12,
"name":"CP",
"d_id":[
"7",
"88"
]
},
{
"id":200,
"name":"AT",
"d_id":[
"7",
"88"
]
}
]
}
}
Otherwise too much iteration can slow down you CPU.