Question

I am trying to make a query to sqlite android to see for example how many users of a given username exist in a table.
This is my function. I must specify that “getContentResolver() != null” and so is variable name.

private int findSelectedUser(String name) {
        int count = 0;

        try {
            String[] whereArgs = new String[] {name};
            String[] PROJECTION = new String[] { MyProvider.SETTINGS_USERNAME };
            Cursor c = getContentResolver().query(MyProvider.SETTINGS_URI,
                    PROJECTION, MyProvider.SETTINGS_USERNAME , whereArgs, null);
            if (c != null) {
                count = c.getCount();
                c.close();
            }
        } catch (NullPointerException e) {

        }
        System.out.println("Found something? " + count);
        return count;
    }

And after running i receive the error from the subject…and don’t get it. In my where clause i have one column, in my where arguments one value.
Please help me make some sence of this, Thank you.

Answer 1

I guess that works:

String[] whereArgs = new String[] {name};
String[] PROJECTION = new String[] { MyProvider.SETTINGS_USERNAME };
Cursor c = getContentResolver().query(MyProvider.SETTINGS_URI,
        PROJECTION, MyProvider.SETTINGS_USERNAME + "=?" , whereArgs, null);
if (c != null) {
    count = c.getCount();
    c.close();
}

If you want to use whereArgs you have to have the same amount of ? in the where as you have items whereArgs

whereArgs will replace the ? in the final database query

String where = "name = ? OR name = ?";
String[] whereArgs = new String[] {
    "Peter",
    "Jim"
};

that results in name = 'Peter' OR name = 'Jim' for the query.

Btw: don’t catch(NullPointerException e) – make your code safe so they can’t happen