update listview dynamically with adapter

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<DataSetObserver> observers = new ArrayList<DataSetObserver>();

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?

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

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