Thank you, but it doesn't seem to work. I get NullPointerExceptions from
the Map. It seems to me this particular predefined map gives access to only
"Name"key property, but i need access to whole object.
In short - i'd really like to know how to get access to *second level*
*array* objects properties.
If you'd be able to help me out, i'd be so grateful!
kolmapäev, 9. aprill 2014 16:21.41 UTC+3 kirjutas prasanna kumar:
>
> Hi,
> It may help you
>
> com.couchbase.lite.View viewItemsByDate = db.getView("booksForCategory");
> viewItemsByDate.setMap(new Mapper() {
>
> HashMap<String, Object> categories = (HashMap<String, Object>) document
> .get("categories");
>
> @Override
> public void map(Map<String, Object> document, Emitter emitter) {
>
> HashMap<String, String> books= (HashMap<String, String>) categories
> .get("books");
>
> Object createdAt = books.get("name");
> if (createdAt != null) {
> emitter.emit(createdAt.toString(), document);
> }
> }
> }, "1.0");
>
> //In Query part
> Query q = v.createQuery();
> QueryEnumerator rowEnum = q.run();
> for (Iterator<QueryRow> it = rowEnum; it.hasNext();) {
> QueryRow row = it.next();
> //BY USING Getkey method we can get name field
> Book b = new Book(row.getKey()));
> //or else we can do like this also
> HashMap<String, HashMap<String, String>> responsibleHaspMap =
> (HashMap<String, HashMap<String, String>>) document
> .getCurrentRevision().getProperty(
> "categories");
> responsibleHaspMap
> .get("books").get("name"));
> }
>
> On Tuesday, April 8, 2014 7:29:31 PM UTC+5:30, Mart-Indrek Süld wrote:
>>
>> I'm developing Couchbase Lite on Android and I have a database, what is
>> initialized according to JSON data file, what looks like this:
>> {
>> "categories": [
>> {
>> "name": "Financial",
>> "books": [
>> {
>> "name": "Rich dad poor dad"
>> },
>> {
>> "name": "How to stay rich"
>> }
>> ]
>> },
>> {
>> "name": "Science",
>> "books": [
>> {
>> "name": "Superman"
>> },
>> {
>> "name": "Green hornet"
>> }
>> ]
>> }
>> ]
>> }
>>
>> How can I receive the "books"-array and gain access to "name"-value for
>> certain category?
>>
>> I separated all the categories in a database to a separate Documents and
>> gave them ID according to category name(Is it reasonable to separate them
>> or it doesn't make any difference?).
>> For example, if i want to get access to "financial" category i type:
>> Document d = database.getExistingDocument("financial");
>> and everything works fine.
>>
>> If i want to get all the categories i type:
>> List<Category> list = new ArrayList<Category>();
>> Database db = manager.getExistingDatabase(DATABASE_NAME);
>> Query query = db.createAllDocumentsQuery();
>> QueryEnumerator rowEnum = query.run();
>> for (Iterator<QueryRow> it = rowEnum; it.hasNext();) {
>> QueryRow row = it.next();
>> Document d = db.getExistingDocument(row.getDocumentId());
>> list.add(new Category((String) d.getProperty("name")));
>> }
>>
>> But how can i get access to "books"-array?
>> So far this is what i've come up with (Read APIs and GrocerySync example):
>> Document d = db.getExistingDocument(categoryID);
>> com.couchbase.lite.View viewItemsByDate = db.getView("booksForCategory");
>> viewItemsByDate.setMap(new Mapper() {
>> @Override
>> public void map(Map<String, Object> document, Emitter emitter) {
>> Object createdAt = document.get("books");
>> if (createdAt != null) {
>> emitter.emit(createdAt.toString(), document);
>> }
>> }
>> }, "1.0");
>> com.couchbase.lite.View v = db.getView("booksForCategory");
>> Query q = v.createQuery();
>> QueryEnumerator rowEnum = q.run();
>> for (Iterator<QueryRow> it = rowEnum; it.hasNext();) {
>> QueryRow row = it.next();
>> Book b = new Book(row.getProperty("name"));//???
>> }
>> But in my oppinion, it doesen't work correctly and this is not the way to
>> do it. It returns wrong results and i'm pretty sure this is not how it
>> should be done.
>>
>> (Oh, Do i define "getView("booksForCategory")" once in the constructor of
>> the DAO or every single time?)
>>
>> Could anyone help me and show me how it's done properly? How to properly
>> get the array of data from the Document so i can get access to properties
>> using Key's?
>>
>> Thanks in advance!
>>
>>
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