CODEWITHSUNDEEP
androidjsongson
ibai.kar
ibai.kar

Reputation: 71

ListString to string with GSON - TypeToken

I'm trying to parse a JSON Array in my Android App with some URLs in it to load into my SQLite DB, here is the code:

JSONArray pics = json.getJSONArray("bilder");
Gson gson = new Gson();
String obj = gson.toJson(pics);
String SQLiteDataBaseQuery = "INSERT INTO images_table (id,desc,imgurl) VALUES('"+i+"', '"+jr_desc+"', '"+obj+"');";
sqLiteDatabase.execSQL(SQLiteDataBaseQuery);

Reading out the DB with the Emulator I can see the String {"values":[URLS here]}. Is it normal that GSON writes this "values" in front of my String List?

So, now I want to call the information from my DB:

Cursor cursor;
Array_links = new ArrayList<String>();
SQLiteGallery sqLiteHelper;
SQLiteDatabase sqLiteDatabase;
sqLiteHelper = new SQLiteGallery(this);
sqLiteDatabase = sqLiteHelper.getWritableDatabase();
cursor = sqLiteDatabase.rawQuery("SELECT * FROM "+SQLiteGallery.TAB_NAME+"", null);
cursor.moveToPosition(0);
Array_links.add(cursor.getString(cursor.getColumnIndex(SQLiteGallery.table_imgurl)));
Gson gson = new Gson();
Type type = new TypeToken<List<String>>().getType();
List<String> img_urls = gson.fromJson(Array_links,type);
for(String url : img_urls)
{
    System.out.println(url);
}

Android Studio gives me the following error:

TypeToken has protected access in 'com.google.gson.reflect.TypeToken'

What does that mean? Is my code wrong?

Thank you

Correct Code here:

     Cursor cursor;
     String urls;
     SQLiteGallery sqLiteHelper;
     SQLiteDatabase sqLiteDatabase;
     sqLiteHelper = new SQLiteGallery(this);
     sqLiteDatabase = sqLiteHelper.getWritableDatabase();
     cursor = sqLiteDatabase.rawQuery("SELECT * FROM 
     "+SQLiteGallery.TAB_NAME+"", null);
     cursor.moveToPosition(0);
     urls = 
     cursor.getString(cursor.getColumnIndex(SQLiteGallery.table_imgurl));
     Gson gson = new Gson();
     Type type = new TypeToken<List<String>>(){}.getType();
     List<String> img_urls = gson.fromJson(urls,type);
     for(String url : img_urls)
     {
     System.out.println(url);
     }

Error: Unable to start activity ComponentInfo{...}: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $

Upvotes: 0

Views: 4006

Answers (1)

ישו אוהב אותך
ישו אוהב אותך

Reputation: 29794

You're forgetting the {}, your code is:

Type type = new TypeToken<List<String>>().getType();

It should be:

Type type = new TypeToken<List<String>>(){}.getType();

Upvotes: 2

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