Android Adapter multiple getView

Question

Hi,

i have read about the issue of getView called multiple times and all the answers. However, i don't find a solution for my problem.

I have a list where rows have two states: read or not. Well, i want to the items seen for first time have a different color and when i scroll the list, they change their color to "read state".

In order to do this, in the method getView of my adapter i set a field isRead when the row for that item is painted. But the problem is the following: since the method getView is called multiple times the field is marked as read and when the list is shown in the screen it appears as if it had already been read.

Any idea to fix this problem?

Thanks

Answer 1

Not the way you want it to work. The reason that getView() is called multiple times is to allow the OS to measure the rows so it knows how to lay them out. You would need to have it marked as read when they click it or check a box or something.

Answer 2

I assume you mean the issue of getView requesting the same view several times.

ListView does this because it needs to get measurements for the views for different reasons (scrollbar size, layout, etc)

This issue can usually be avoided by not using the "wrap_content" property on your listview.

Other than that, using getView to determine if a view has been displayed is simply a bad idea. ListView has many optimizations that mess with the order getView is called on for each row, so there is no way to know what will happen and your app will start showing odd behavior.

Try to avoid any relationship between the view and the data other than the concept of view as a display of that data.

Instead, have some worker thread or event listener in your listactivity watch the list for which items in the list have been displayed to the user, update the data, and call dataSetChanged on your adaptor.