Archives for: July 2010, 31

ListActivity Cheetsheet

July 31st, 2010

ListActivity contains in android.app.

ListView

Custom define Activity Layout

ListActivity hosts a ListView object. User can set a custom layout for activity, but make sure that it contains a ListView which id is @id/android:list

Set empty view

  1. Define <FrameLayout> in resource layout file which contains empty view and list view
  2. At onCreate() call getListView().setEmptyView(findViewById(R.id.empty)

ListAdapter

ListActivity uses ListAdapter to get data and custom sub view.

User generally extends BaseAdapter to define his own adapter.

Basic overriding methods

  • public int getCount() Get total number of list
  • public Object getItem(int position) Get the data/reference to data at postion
  • public long getItemId(int position) Get the unique id of data
  • public View getView(int position, View convertView, ViewGroup parent) Create a view for position. If convertView is not null, it pointer to previous created view, you can reuse it.

Selectable and Clickable

areAllItemsEnabled()/isEnabled() are overriding to set view selectable and clickable.

Separator

Add a list item view, and disable it, and it will serve as a separator.

Expandable list

Solution 1: Make item view contains several views which can be configure visiuable or not visiuable.

Notify Data Change

notidyDataSetChanged()

Predefined Adapter:ArrayAdapter and SimpleCursorAdapter

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