Android SQL Cursor-CodePudding

I'm using a SQLite database on Android and I need a particular value from the table. I have a DataBaseHelper class.

private static final String TABLE_NAME = "my_task";
private static final String COL1 = "ID";
private static final String COL2 = "name";
private static final String COL3 = "status";
private static final String COL4 = "rec";

I have to get the value of column rec for the given name (it's either 0 or 1). I have this function to do the task:

public Cursor getRec(String task) {
    SQLiteDatabase db = this.getWritableDatabase();

    String q = "SELECT "   COL4   " FROM "   TABLE_NAME   " WHERE "   COL2   " = ?";

    Cursor data = db.rawQuery(q, new String[] { task });
    return data;
}

I don't know how to get the required value from this returned cursor. I'm new to this, so please help me with this.

CodePudding user response：

The function getRec() returns a Cursor and you can call it like:

Cursor c = getRec("John");

Then you must check if the cursor contains any rows and if it does you can extract the value of the 1st row:

String rec;
if (c.moveToFirst()) rec = c.getString(0);
c.close();

You can check the value of the variable rec:

if it is null then 'John' was not found in the table
if it is not null then the variable rec contains the value of the column rec of the table.

I assume that you expect only 1 row as the result of your query.

If you expect more than 1 rows then use a loop that collects all the recs returned in a list:

ArrayList<String> list = new ArrayList();
while (c.moveToNext()) {
    list.add(c.getString(0));
}
c.close();