Dropbox sync api write string in JSON file

Question

I'm trying to write a JSON string in txt file that contains other JSON objects. The structure of the txt file is:

{
"array": [
    {
        "id": "1",
        "owner": "email_string",
        "title": "title_string",
        "content": "content_string"
    },
    {
        "id": "2",
        "owner": "email_string",
        "title": "title_string",
        "content": "content_string"
    }
]
}

Now in my code, I have built the new String JSON formatted to append after the last object but I don't know how to write the new JSON string after the last JSON object and before the ']' character. The DropboxFile object has method as getInputStream(), getWriteStream(), getAppendStream(). I suppose i should use one of them but I don't know how. Can anyone help me?

Here is the code where i need to put the writing:

DbxFileSystem dbxFs;

dbxFs = DbxFileSystem.forAccount(mDbxAcctMgr.getLinkedAccount());

DbxPath path = new DbxPath(NOTE_DB_PATH);
dbxFs.syncNowAndWait();
DbxFile file = dbxFs.open(path);

String JSONNote = JSONParser.buildJSONNoteString(title, content, currentUserEmail, id)+"\n";

// TODO Here I have to find the place to write my JSONNote string

dbxFs.syncNowAndWait();

file.close();
dbxFs.shutDown();
} catch (DbxException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();

}

SOLUTION:

DbxFileSystem dbxFs;

dbxFs = DbxFileSystem.forAccount(mDbxAcctMgr.getLinkedAccount());

DbxPath path = new DbxPath(NOTE_DB_PATH);
dbxFs.syncNowAndWait();
DbxFile file = dbxFs.open(path);

String JSONNote = JSONParser.buildJSONNoteString(title, content, currentUserEmail, id)+"\n";
JSONObject newJsonObj = new JSONObject(JSONNote);

String dataString = readFile(file);
JSONObject dataJSON = new JSONObject(dataString);

dataJSON.accumulate("array", newJsonObj);

file.writeString(dataJSON.toString());

dbxFs.syncNowAndWait();
file.close();
dbxFs.shutDown();

readfile() method:

    protected String readFile(DbxFile file) throws DbxException, IOException{
    FileInputStream in = file.getReadStream();
    int size = in.available();
    byte c[] = new byte[size];
    for (int i = 0; i < size; i++) {
        c[i] = (byte) in.read();
    }
    String filedata = new String(c, "utf-8");

    in.close();
    return filedata;
}

Answer 1

First read your file using following code

public String readFile(String filepath) throws IOException {
File f = new File(filepath);
FileInputStream in = new FileInputStream(f);
int size = in.available();
byte c[] = new byte[size];
for (int i = 0; i < size; i++) {
    c[i] = (byte) in.read();
}
String filedata = new String(c, "utf-8");
return filedata;}

Then form JSONArray as i have looked at u r JSON structure you can do it in following way

String data = readFile("your filepath");

JSONObject data = new JSONObject(data);

JSONArray newarray = (JSONArray)data.get("array");

Then you can use "put" method of JSONArray and append data in existing jsonarray . so it will be like

newarray.put(index,your_data);

then use following code to write the same data to file

FileOutputStream fos = new FileOutputStream("your file name", false);
                    PrintStream ps = new PrintStream(fos);
                    ps.append(data.toString());

and hopefully you are done