Question

I was reading the new Android Design Standards here: http://developer.android.com/design/patterns/selection.html and was wondering first how to make my ListView selectable (because long presses are now supposed to select items, not show a context menu like before), then to figure out how to pass that information to the ActionBar so I can make a contextual ActionBar based on what is selected (and how many items are selected). I’ve checked out several sites, including http://www.vogella.de/articles/AndroidListView/article.html but it doesn’t show how to do it for ICS with the ActionBar.

I apologize for not giving any code, but I haven’t had to do anything with listviews aside from making custom ones.

Answer 1

For the first part (select list item), you need to do a couple things:

-Depending on the context, set your ListView to either single or multiple choice (depending on your app), using the setChoiceMode method.

lv.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
// or
lv.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

-in order to mark the item as selected, just listen for a long press and call the ListView’s setItemChecked method.

lv.setItemChecked(position, true);

Finally, in order for the listview item to show as selected, you need to add the following attribute to the custom XML layout for that listview item:
android:background="?android:attr/activatedBackgroundIndicator"

For creating contextual Action Bar, the process is a little more detailed, but it’s outlined in the Android Developer guide in the Using Contextual Action Mode section.