And for those not on #monodroid...
On Mar 15, 2012, at 7:07 AM, Michel wrote:
...
> -- Class ListViewCategories --
> public class ListViewCategories : BaseAdapter
...
> public override View GetView (int position, View convertView,
> ViewGroup parent)
The intent of the `convertView` parameter is to reuse an existing instance that
you allocated, thus reducing the number of objects that exist, reducing memory
pressure, and keeping performance up:
http://androidapi.xamarin.com/?link=M:Android.Widget.IAdapter.GetView
convertView:
The old view to reuse, if possible.
The problem? While `convertView` is checked:
> View vi = convertView;
> if (convertView == null)
> {
> //Log.Debug("--> ConvertView null");
> vi = inflater.Inflate(Resource.Layout.DialogCategories, null);
> // Log.Debug("<-- ConvertView null");
> }
...nothing is done with it. Instead, a new view is always created and returned:
> LinearLayout view = new LinearLayout(context);
...
> return view;
> }
The result, as you see, is a constantly increasing gref count.
There are two solutions here:
1. Call GC.Collect() more often so that the unused LinearLayout instances will
be collected. However, this may or may not work; it depends on what Android
does with the returned instances. If it retains a reference to all of them,
then they will never be collected.
2. Use the `convertView` parameter as it is intended: actually reuse the view.
For example, in this instance the `convertView` will likely be a LinearLayout
instance, as constructed by the GetView() method, so you could grab the already
existing TextView instances and change their strings instead of creating a new
LinearLayout + TextView object graph.
- Jon
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