How to iterate a ArrayList inside a HashMap Android -

i created hashmap this

hashdatachild = new hashmap<arraylist<string>, list<string>> 

what want iterate arraylist inside hashmap

basically want achieve

arraylist<string> arrayofstring;  (integer = 0; i<=header_data.size(); i++){      hashdatachild.put(arrayofstring.get(i), child); } 

so whenever loops, each header, child displayed.

i'm trying create expandable listview this. how can achieve this?

is necessary put hashmap inside arraylist this

arraylist<hashmap<arraylist<string>, list<string>>>  

because example , found code there no explanation on , how do.

`list<string>` second argument in hashmap created  child = new arraylist<string>();      child.add("child 1");     child.add("child 2");     child.add("child 3"); 

i used arraylist<string> first argument header data multiple columns database

you can this...

import java.util.arraylist;  import java.util.hashmap;    import java.util.iterator;    import java.util.map;    import java.util.map.entry;  hashdatachild = new hashmap<arraylist<string>, list<string>>   iterator<entry<arraylist<string>, arraylist<string>>> it=map.entryset().iterator(); while(it.hasnext()){   map.entry<arraylist<string>, list<string>> pair = (map.entry)it.next();   arraylist<string> arraylist=pair.getkey();   //iterate.... here iterate logic list<string> list=pair.getvalue(); }