how to loop add statement in array lists

Question

   public static void main(String[] args) {

      ArrayList<String> names = new ArrayList<String>();

      names.add(JOptionPane.showInputDialog("Enter type of pie"));

   }

How would I loop this statement? I've tried dowhile (!names.equalsIgnoreCase("q")); but it can't find it.

      names.add(JOptionPane.showInputDialog("Enter type of pie"));

Does it work before you add the for loop? I.e does the code you posted above compile? — SwiftySwift
– SwiftySwift, Commented Jul 11, 2015 at 16:18
names is a List, obviously it cannot equal "q"; regardless of case. What exactly are you trying to do?? — Boris the Spider
– Boris the Spider, Commented Jul 11, 2015 at 16:18
I'm trying to repeat the input dialog until the user enters q — dan
– dan, Commented Jul 11, 2015 at 16:20

Michele · Accepted Answer · 2015-07-11 23:32:51Z

1

This work fine.

     String str = null;
     List<String> names = new ArrayList<String>();
     do
     {
      str = JOptionPane.showInputDialog("Enter type of pie");
   if(!str.equalsIgnoreCase("q"))
      names.add(str);
     }while(!str.equalsIgnoreCase("q"));

edited Jul 11, 2015 at 23:32

answered Jul 11, 2015 at 16:35

Michele

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2 Comments

Shar1er80 Over a year ago

So adding "q" to the list is okay?

Boris the Spider Over a year ago

You can just make it into a while loop and avoid adding q to the List that way - this is rather ugly.

Shar1er80 · Accepted Answer · 2015-07-11 16:36:51Z

1

Try this...

public static void main(String[] args) throws Exception {
    List<String> names = new ArrayList();
    String input = "";
    while (!input.equalsIgnoreCase("q")) {
        input = JOptionPane.showInputDialog("Enter type of pie");
        if (!input.equalsIgnoreCase("q")) {
            names.add(input);
        }
    }

    System.out.println(names);
}

answered Jul 11, 2015 at 16:36

Shar1er80

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Comments

Yon Kornilov · Accepted Answer · 2015-07-11 16:55:42Z

In your loop, you should iterate through the names list and call equalsIgnoreCase("q") on each element, adding another input dialog each iteration.

consider:

while (names.isEmpty() || !names.get(names.size() - 1).equalsIgnoreCase("q"))
{
    names.add(JOptionPane.showInputDialog("Enter type of pie"));
}

And if you'd like to disregard the name of the pie "q":

while (names.isEmpty() || !names.get(names.size() - 1).equalsIgnoreCase("q"))
{
    names.add(JOptionPane.showInputDialog("Enter type of pie"));
}
// populates the ArrayList names with the JOptionPane user input
if (!names.isEmpty())
{
    names.remove(names.size() - 1);
    // remove the last name inputted by the user
    // since the only way to terminate the loop is by entering "q",
    // you are removing the name of "q" from the list.
}

EDIT: this is a better implementation since it only adds the names which aren't "q":

String userInput = new String();
while (!userInput.equalsIgnoreCase("q"))
{
    userInput = JOptionPane.showInputDialog("Enter type of pie");
    if (!userInput.equalsIgnoreCase("q"))
    {
        names.add(userInput);
    }
}

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