I have a HTML list of about 500 items and a "filter" box above it. I started by using jQuery to filter the list when I typed a letter (timing code added later): $('#filter').keyup( function() { var jqStart = (new Date).getTime(); var search = $(this).val().toLowerCase(); var $list = $('ul.ablist > li'); $list.each( function() { if ( $(this).text().toLowerCase().indexOf(search) === -1 ) $(this).hide(); else $(this).show(); } ); console.log('Time: ' + ((new Date).getTime() - jqStart)); } ); However, there was a couple of seconds delay after typing each letter (particularly the first letter). So I thought it may be slightly quicker if I used plain Javascript (I read recently that jQuery's each function is particularly slow). Here's my JS equivalent: document.getElementById('filter').addEventListener( 'keyup', function () { var jsStart = (new Date).getTime()...
For an ArrayAdapter, notifyDataSetChanged only works if you use the add, insert, remove, and clear functions on the Adapter.
ReplyDeleteWhen an ArrayAdapter is constructed, it holds the reference for the List that was passed in. If you were to pass in a List that was a member of an Activity, and change that Activity member later, the ArrayAdapter is still holding a reference to the original List. The Adapter does not know you changed the List in the Activity.
Your choices are:
Use the functions of the ArrayAdapter to modify the underlying List (add, insert, remove, clear, etc.)
Re-create the ArrayAdapter with the new List data.
Create your own class derived from BaseAdapter and ListAdapter that allows changing of the underlying List data structure.
Then notifyDataSetChanged will work.
You can use the runOnUiThread method as follows. If you're not using a ListActivity, just adapt the code to get a reference to your ArrayAdapter.
ReplyDeletefinal ArrayAdapter adapter = ((ArrayAdapter)getListAdapter());
runOnUiThread(new Runnable() {
public void run() {
adapter.notifyDataSetChanged();
}
});
I had the same problem and I prefer not to replace the entire ArrayAdapter with a new instance continuously. Thus I have the AdapterHelper do the heavy lifting somewhere else.
ReplyDeleteAdd this where you would normally (try to) call notify
new AdapterHelper().update((ArrayAdapter)adapter, new ArrayList<Object>(yourArrayList));
adapter.notifyDataSetChanged();
AdapterHelper class
public class AdapterHelper {
@SuppressWarnings({ "rawtypes", "unchecked" })
public void update(ArrayAdapter arrayAdapter, ArrayList<Object> listOfObject){
arrayAdapter.clear();
for (Object object : listOfObject){
arrayAdapter.add(object);
}
}
}