What is the difference between "int" and "long" argument in onItemClick in Android

Question

When we implement OnItemClickListener, we have to implement onItemClick method which is an abstract method in OnItemClickListener interface. In onItemClick method there are four arguments.

public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
    Toast.makeText(this, "Clicked on : " + arg2 + " long arg : " + arg3, 
                   Toast.LENGTH_LONG).show();
}

What I need to know is the difference between last two arguments (int arg2, long arg3). As you can see in my code, when I try to Toast it I get the same value for both arguments.

Answer 1

I had the same question as you. However, the answers here were not extremely helpful. I don't support the go-look-it-up-yourself answers, especially when the so called documentation is so unclear. I did look it up myself, though, and the following is what I found.

The int value is the position of the view in the parent. For a ListView, it is the row number. The top row is position 0, the second row is position 1, the third row is position 2, etc. Note that if your ListView has a header view (like if you did ListView.addHeaderView(View)) then the header view would be position 0 and the actual rows would start their numbering at 1.

Sometimes the long value is the same as the int position and sometimes it is different. If you are using an ArrayAdapter or SimpleAdapter then they are the same (except in the case that there is a header view and then they are off by one). For a CursorAdapter (and consequently a SimpleCursorAdapter) the long id returns the row id of the table, that is, _id. It is a long rather than an int because a database could theoretically have more rows than an int could hold whereas a ListView wouldn't.

Here are a few other related answers:

• https://stackoverflow.com/a/25622142/3681880
• https://stackoverflow.com/a/9863279/3681880
• https://stackoverflow.com/a/12966006/3681880
• https://stackoverflow.com/a/24531354/3681880