Question

I am calling a method that passes in a variable. I want to be able to compare this variable to all the items in an ArrayList to see if there is a match.

This is my code…

private boolean input;
private ArrayList chcekItem = new ArrayList();

public void setAction(String action) {
    input=true; 

    if (getChcekItem().isEmpty()) {
        getChcekItem().add(action);
    }
    else {            
        Iterator iterators = getChcekItem().iterator();
        while (iterators.hasNext()) {                
            if (iterators.next()==action) {
                System.out.println(iterators.next()+"="+action);
                input=false;
            }
        }            
        if (input) {
            getChcekItem().add(action);
            System.out.println("The item " + action + " is Successfully Added to     array");
        }
        else{
            System.out.println("The item " + action + " is Exist");
        }
    }
}

My code isn’t working as I had expected. Could someone please help me fix the problem.

Answer 1

I take it that the checkItem variable is a List of Strings, thus it should be defined like this:

private List<String> checkItem = new ArrayList<String>();

When comparing an String you don’t use string1==string2 but string1.equals(string2);

So

(iterators.next()==action) 

should be:

(iterators.next().equals(action))

Remember to check the string for null values.

So the whole code could look like this:

private boolean input;
private List<String> chcekItem= new ArrayList<String>();

public void setAction(String action) {
input=true; 
if (getChcekItem().isEmpty()) {
        getChcekItem().add(action);
    } else {
        //Foreach loop instead of an iterator ;)
        for(String item : chcekItem) {
            if(item.equals(action)) {
                System.out.println(item+"="+action);
                input=false;
                //We can jump out of the loop here since we already found a matching value
                break;
            }
        }         
        if (input) {
            getChcekItem().add(action);
            System.out.println("The item " + action + " is Successfully Added to               array");
        }else{
            System.out.println("The item " + action + " is Exist");
        }
      }
    }
}