Custom cursor adapter calling bindView multiple times

Question

I have been suffering this issue for months and months (but now I am performance tuning). However, I now desperately need to know why my adapter feels it is necessary to run bindView up to 4 times on a record.

I have a custom cursor adapter that populates a gridview.

Some debug to show what's going on:

03-08 14:46:47.980: I/AdapterCursorGrid(20724): newView()
03-08 14:46:48.470: I/AdapterCursorGrid(20724): bindView()
03-08 14:46:48.570: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:48.570: I/AdapterCursorGrid(20724): bindView() Record Id: 1
03-08 14:46:48.570: I/AdapterCursorGrid(20724): bindView() Cursor Position: 0
03-08 14:46:48.570: I/AdapterCursorGrid(20724): bindView() View Type: 0
03-08 14:46:48.570: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:48.600: D/AdapterCursorGrid(20724): bindView() Avatar empty...
03-08 14:46:48.690: D/AdapterCursorGrid(20724): bindView() Picture creation...
03-08 14:46:49.490: I/AdapterCursorGrid(20724): bindView()
03-08 14:46:49.501: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:49.501: I/AdapterCursorGrid(20724): bindView() Record Id: 1
03-08 14:46:49.501: I/AdapterCursorGrid(20724): bindView() Cursor Position: 0
03-08 14:46:49.501: I/AdapterCursorGrid(20724): bindView() View Type: 0
03-08 14:46:49.501: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:49.521: D/AdapterCursorGrid(20724): bindView() Avatar empty...
03-08 14:46:49.521: D/AdapterCursorGrid(20724): bindView() Picture creation...
03-08 14:46:50.320: I/AdapterCursorGrid(20724): newView()
03-08 14:46:51.170: I/AdapterCursorGrid(20724): bindView()
03-08 14:46:51.180: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:51.180: I/AdapterCursorGrid(20724): bindView() Record Id: 1
03-08 14:46:51.180: I/AdapterCursorGrid(20724): bindView() Cursor Position: 0
03-08 14:46:51.190: I/AdapterCursorGrid(20724): bindView() View Type: 0
03-08 14:46:51.190: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:51.190: D/AdapterCursorGrid(20724): bindView() Avatar empty...
03-08 14:46:51.200: D/AdapterCursorGrid(20724): bindView() Picture creation...
03-08 14:46:51.870: I/AdapterCursorGrid(20724): bindView()
03-08 14:46:51.896: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:51.896: I/AdapterCursorGrid(20724): bindView() Record Id: 1
03-08 14:46:51.900: I/AdapterCursorGrid(20724): bindView() Cursor Position: 0
03-08 14:46:51.900: I/AdapterCursorGrid(20724): bindView() View Type: 0
03-08 14:46:51.900: I/AdapterCursorGrid(20724): --------------------------
03-08 14:46:51.900: D/AdapterCursorGrid(20724): bindView() Avatar empty...
03-08 14:46:51.900: D/AdapterCursorGrid(20724): bindView() Picture creation...

The "Avatar empty..." and "Picture creation..." is simply debug that tells me it is processing and updating 2 particular ImageViews.

Why o why is bindView running so many times? What are the reasons for this and what can I do to resolve this?

Logically speaking I expect bindView to run once (and once each time the adapter is updated), am I wrong in thinking this?

Answer 1

The operating system may call bindView multiple times so that it can measure and lay out the list correctly. This is not a bug so much as the way it has to be. This, along with smoothness of scrolling, is why bindView implementations need to be as efficient as possible. There are some nice tips and tricks you can use detailed on the Android Developers Page.

Answer 2

I also found that bindView was being called many more times than expected. My ListView height was set to wrap_content. After changing it to match_parent the number of calls reduced drastically.

Credit for this solution goes to the answer for this question Custom CursorAdapater's bindView called 77 times...have I done something wrong?