AppProvider.java

  ...

@Nullable
    @Override
    public Uri insert(@NonNull Uri uri, @Nullable ContentValues contentValues) {
        final int match = uriMatcher.match(uri);
        switch (match){
            case WORDS_CODE :
                return insertData(uri, contentValues);
            default:
            throw new IllegalArgumentException("Valid URI " + uri);
        }
    }

    /**
     * @param uri : caller should provide the Uri he need
     * @param content: caller should provide the Data of the inserted Object
     * @return the new Uri for inserted Object
     */
    private Uri insertData(Uri uri, ContentValues content) {
        SQLiteDatabase database = mDbHelper.getWritableDatabase();
        long id = database.insert(uri.getPath(), null, content);
        if (id != -1) {
            return ContentUris.withAppendedId(uri, id);
        }
        else{
            return null ;
        }
        
    }

            ...