update listview dynamically with adapter

Question

This tutorial uses a SimpleAdapter which works fine  but I need to update the arrays in the adapter when new data is entered   Could you please guide me on how to update a ListView using something other than a SimpleAdapter

User · Answer

If you create your own adapter  there is one notable abstract function   public void registerDataSetObserver DataSetObserver observer                You can use the given observers to notify the system to update   private ArrayList lt DataSetObserver gt  observers   new ArrayList lt DataSetObserver gt      public void registerDataSetObserver DataSetObserver observer        observers add observer     public void notifyDataSetChanged        for  DataSetObserver observer  observers            observer onChanged              Though aren t you glad there are things like the SimpleAdapter and ArrayAdapter and you don t have to do all that

User · Answer

Use a ArrayAdapter backed by an ArrayList  To change the data  just update the data in the list and call adapter notifyDataSetChanged

User · Answer

Most people recommend using notifyDataSetChanged    but I found this link pretty useful  In fact using clear and add you can accomplish the same goal using less memory footprint  and more responsibe app    For example   notesListAdapter clear    notes   new ArrayList lt Note gt     notesListAdapter add todayNote   if  birthdayNote    null  notesListAdapter add birthdayNote       no need to refresh  let the adaptor do its job

User · Answer

I created a method just for that  I use it any time I need to manually update a ListView  Hopefully this gives you an idea of how to implement your own  public static void UpdateListView List lt SomeObject gt  SomeObjects  ListView ListVw            if ListVw    null                final YourAdapter adapter    YourAdapter  ListVw getAdapter               You ll have to create this method in your adapter class  It s a simple setter          adapter SetList SomeObjects            adapter notifyDataSetChanged              I m using an adapter that inherites from BaseAdapter  Should work for any other type of adapter

User · Answer

SimpleListAdapter s are primarily used for static data  If you want to handle dynamic data  you re better off working with an ArrayAdapter  ListAdapter or with a CursorAdapter if your data is coming in from the database   Here s a useful tutorial in understanding binding data in a ListAdapter  As referenced in this SO question

User · Answer

add and remove methods are easier to use  They update the data in the list and call notifyDataSetChanged in background   Sample code   adapter add  your object    adapter remove  your object

[android] update listview dynamically with adapter

Examples related to android

Examples related to listview