I have a Array list which contains Objects of Restaurants
ArrayList<Restaurants> array_sort = new ArrayList<Restaurants>();
Restaurant object is contain its name and Id. Beside of that there is a Alphabetical Index. I need to go for the specific letter in the array when user click on the index letter. This image will give you a good idea.
Thanks in advance !
Using an ArrayList for this task is not a good idea because it doesn't provide any efficient solution to your problem. I'd suggest to use a TreeMap<String,Resturant>. The good thing of the TreeMap is that it has the method
public NavigableMap<K,V> subMap(K fromKey,
boolean fromInclusive,
K toKey,
boolean toInclusive)
which returns a portion of the map that contains just the items you need for the specific letter, already sorted. This submap is backed by the full one so it's a light weight object.
You can easily do something like subMap("a", true, "b", false).
You could enumerate the items in each of the letters before that letter and then use http://developer.android.com/reference/android/widget/ListView.html#smoothScrollToPosition(int)
Easiest option can be to have a map also mapping display indices to list of restaurant objects.
