Android - Returning a position of an item in an ArrayList that appears multiple times -

i have 3 arraylists, 2 strings , last 1 integer.

the first arraylist contains specific variant (variantarray) product flavor variant of cola, second 1 contains unit (unitarray) contains unit size (80oz, 500ml, 1l) of product, , last 1 quantity *(quantityarray).

this class use.

public class currentorderclass {    //arraylists   private arraylist<string> variantarray = new arraylist<string>();   private arraylist<string> unitarray = new arraylist<string>();   private arraylist<integer> quantityarray = new arraylist<integer>();     //todo arraylist functions   public arraylist<string> getunitarray() {       return unitarray;   }    public void setunitarray(arraylist<string> unitarray) {       this.unitarray = unitarray;   }    public void addtounitarray(string unit){       this.unitarray.add(unit);   }      public arraylist<integer> getquantityarray() {       return quantityarray;   }    public void setquantityarray(arraylist<integer> quantityarray) {       this.quantityarray = quantityarray;   }    public void addtoquantityarray(int quantity){       this.quantityarray.add(quantity);   }    public arraylist<string> getvariantarray() {       return variantarray;   }    public void setvariantarray(arraylist<string> variantarray) {       this.variantarray = variantarray;   }    public void addtovariantarray(string variantarray){       this.variantarray.add(variantarray);   }     @override       public string tostring() {          return "[ product=" + productname + ", variants=" +              variants + " , unit=" + unit + " , quantity=" + quantity + "]";       }  } 

i take in user input user chooses variant, unit, , quantity , input stored in respective arraylists.

however, i'm having problem updating arraylists when user inputs variant , unit exists in arraylists different quantity. want not add new entry, update current arraylists in such way when user inputs variant , unit different quantity, i'd update quantity.

the first thing tried see if input exists in arraylist using indexof(userinputvariant) , check if matches indexof(userinputunit), mean user input repeated already. however, don't think indexof runs on logic , value returns value found first instance of userinputvariant string.

the second attempt tried using each loop, however, i'm once again having hard time returning index want properly.

i instantiate object of currentorderclass named currentorder , prepopulated first 10 elements of variantarray "grape"

after that, tried if-else statement:

if( (currentorder.getvariantarray().indexof(product.getvariant()[variantposition]) ==      currentorder.getunitarray().indexof(product.getunit()[position])  

however, mentioned above, indexof returns int first found string told find, don't think checks if exists after position.

the second code tried use for-each , return position there, again, returned position = 0.

for( string grape : currentorder.getvariantarray() ){       log.d("angelo", "retrived element: " + grape             + " @ position = " + currentorder.getvariantarray().indexof(grape)); } 

i'm thinking of running for-each loop inside for-each loop don't know how make return proper position want.

does have idea on how make work properly? need return position of item appears multiple times in variantarray "cross-referencing" unitarray. thanks.

one loop enough in case.

this thing like:

isexist = false; for(index = 0; index<variantarray.size(); index++){     if(variantarray.get(index) == userchoicevariant &&         unitarray.get(index) == userchoiceunit){         //update quantity         isexist = true;     } } if(!isexist){     //insert order }