Using content values to convert string to integer

Question

I am currently working from a project used in a tutorial that displays contacts in a listview. All the fields in the database are used and saved as strings. A custom adapter class is being used for the edit and delete buttons - the buttons appear on the listview, per item. Clicking on edit leads to a separate activity to in which details for that record are parsed in.

I have added another button that I'd like to update a record when clicked and reload the activity. When you press the button it calls a method from the connector method:

    public void updateContact(long id, String name, String phone, String mail,
        String fb, byte[] blob) {
    ContentValues cv = new ContentValues();
    cv.put(Contacts.NAME, name);
    cv.put(Contacts.PHONE, phone);
    cv.put(Contacts.MAIL, mail);
    cv.put(Contacts.FB, fb);
    cv.put(Contacts.IMAGE, blob);

    db = sqlHp.getWritableDatabase();
    db.update(Contacts.TABLE, cv, Contacts.ID + "=" + id, null);
    db.close();
}

I would like phone to convert the string to an integer, increment the value by 1 and then save using contentvalues as a string. Here is what I've tried:

    public void updateContact(long id, String name, String phone,
        String mail, String fb, byte[] blob) {
    ContentValues cv = new ContentValues();

    cv.put(Contacts.NAME, name);
    int phone1 = 0;
    phone1 = (Integer) cv.getAsInteger(Contacts.PHONE);

        phone1++;


        phone = String.valueOf(phone1);

        cv.put(Contacts.PHONE, phone);


    cv.put(Contacts.MAIL, mail);
    cv.put(Contacts.FB, fb);
    cv.put(Contacts.IMAGE, blob);

    db = sqlHp.getWritableDatabase();
    db.update(Contacts.TABLE, cv, Contacts.ID + "=" + id, null);
    db.close();
}

This gives me a null pointer exception error. I'm not sure where to go from here.

This is the method from the custom adapter which holds the onclick method

    setPresent = (ImageButton) v.findViewById(R.id.setPresent);
    setPresent.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {

            sqlCon.updateContact(id, name, phone, email,  fb, image);
            Intent intent = new Intent(context, MyContactsActivity.class)
                    .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(intent);

        }

    });

It's when I click this button the null pointer exception error occurs. These are the lines it flags up:

                sqlCon.updateContact(id, name, phone, email,  fb, image);

- from the customadapter

and

        phone1 = (Integer) cv.getAsInteger(Contacts.PHONE);

- from the connector

Which line throws the NullPointerException? Can you please post the error from LogCat? — Tamby Kojak
– Tamby Kojak, Commented Apr 5, 2014 at 23:14
it's the line 'phone1 = (Integer) cv.getAsInteger(Contacts.PHONE);' I will update the post with the logcat error(s) — Drakora
– Drakora, Commented Apr 5, 2014 at 23:16
One definite problem here is that you are declaring a set of new ContentValues(); and then trying to get the value Contacts.PHONE when it is clear that nothing has been added at that point. It's possible that that could be your error. — Tamby Kojak
– Tamby Kojak, Commented Apr 5, 2014 at 23:20
You are creating a new cv...then you try to geht a value...it's null obviously, as you didn't put anything in before...edit: too slow on phone — ElDuderino
– ElDuderino, Commented Apr 5, 2014 at 23:23
so instead of doing this in the connector class it would be best to convert to int and increment in another class? — Drakora
– Drakora, Commented Apr 5, 2014 at 23:29

janos · Accepted Answer · 2014-04-05 23:32:44Z

2

This part doesn't really make sense in your code:

ContentValues cv = new ContentValues();
int phone1 = (Integer) cv.getAsInteger(Contacts.PHONE);

You are trying to get Contacts.PHONE from a ContentValues you just created.

Perhaps you wanted to do something like this instead:

cv.put(Contacts.PHONE, Integer.parseInt(phone) + 1);

If you clean up this part, the NullPointerException will probably disappear naturally.

Also, it's safer to update tables using ? placeholders for parameters instead of puttin them in the query string, like this:

db.update(Contacts.TABLE, cv, Contacts.ID + " = ?", new long[]{id});

edited Apr 5, 2014 at 23:32

answered Apr 5, 2014 at 23:27

janos

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1 Comment

Drakora Over a year ago

Ah, I am indeed using my new ContentValues incorrectly. I'm going to keep the field as a string in the database but have the string in the textveiw convert to int, ++, and then save it's contents.

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