Getting data from SQLite database to String Android

Question

I am trying to get information from my database and put it into a string to print it on screen. i thought i could use the code below to do it but it gives out some information about the cursor instead of the information inside the cursor.

datasource = new DataBaseHelper(this);
datasource.open();
Cursor c = datasource.getAllGoals();
startManagingCursor(c);
String g = c.toString();
goal.setText(g);
datasource.close();

how information? could you more specificate it? with String g = c.toString() you only get string representation of cursor object.for getting informations from cursor you should use getters and method which allow to you passing via data. — Simon Dorociak
– Simon Dorociak, Commented May 26, 2012 at 16:53

Dhruv Gairola · Accepted Answer · 2012-05-26 17:18:07Z

1

The cursor can be thought of as a pointer to some underlying data. Running c.toString() on the cursor object would print the default Cursor class' implementation of its string representation (an at-sign character @ and the unsigned hexadecimal representation of the hash code of the object) which is not what you want.

To retrieve underlying database data, you will need to call c.getString(columnIndex) (source), or whatever column datatype you require for that particular column index.

Here's an example modified from source:

Say you have created a table

private static final String DATABASE_CREATE = 
            "create table comments ( "
            + "_id integer primary key autoincrement, "
            + "comment text not null);";

and your getAllGoals function returns a cursor which points to data about both _id and comment. Now you only want to show the details about the comment column. So you have to run c.getString(1). Suppose your getAllGoals function returns a cursor which only points to data about the comment column. Now you have to run c.getString(0).

I would recommend that you download the source code in the provided example and go through how data is retrieved from a cursor.

EDIT:

    public List<Comment> getAllComments() {
        List<Comment> comments = new ArrayList<Comment>();

        Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS,
                allColumns, null, null, null, null, null);

        cursor.moveToFirst();
        while (!cursor.isAfterLast()) {//retrieve data from multiple rows
            Comment comment = cursorToComment(cursor);
            comments.add(comment);
            cursor.moveToNext();
        }
        // Make sure to close the cursor
        cursor.close();
        return comments;
    }

    private Comment cursorToComment(Cursor cursor) {
        Comment comment = new Comment();
        comment.setId(cursor.getLong(0));
        comment.setComment(cursor.getString(1));
        return comment;
    }

source

edited May 26, 2012 at 17:18

answered May 26, 2012 at 16:53

Dhruv Gairola

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7 Comments

Darren Murtagh Over a year ago

what does column index refer to. would i need to change that or is that just what is needed>

Darren Murtagh Over a year ago

so if i was getting say several bits of information from the database i would run this several times for each bit of information?

Dhruv Gairola Over a year ago

if you mean that getAllGoals returns several pieces of information, you will need to use a while loop. check out my answer again for an updated example.

Dhruv Gairola Over a year ago

note that you will need to know what type of data is being pointed to by the cursor returned by your getAllGoals function. this way, you can call the appropriate getter method on your cursor.

Darren Murtagh Over a year ago

ok so if it was a get int its getInteger(0); i see. though when i ran the get string it crashed the application

|

Parag Chauhan · Accepted Answer · 2012-05-26 17:03:58Z

0

openDataBase();
Cursor c = myDataBase.rawQuery("SELECT * FROM tb_aa_City where City_Name = '"+cityname+"'", null);
if (c.getCount() > 0) {
    c.moveToFirst();
    seqid = c.getString(4);
    System.out.println("In DB..getSequenceID..."+seqid);
    }
    c.close();
    myDataBase.close();
    SQLiteDatabase.releaseMemory();

answered May 26, 2012 at 17:03

Parag Chauhan

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2 Comments

Darren Murtagh Over a year ago

how do i get the c.getString(int); to point to the right information

Parag Chauhan Over a year ago

c.getString(Colomn number) // give database Column number

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