Question

How do remove an object from list and add to another with indexes (java)

Ex: I have two separate list classes, Dogs and WalkedDogs, so once a dog from the Dog list has been walked, I want to remove that dog from the Dog list and at the same time then add it to the WalkedDogs list. By doing so via ui, so when main runs, the user is shown a list of Dogs, and chooses a dog with index (so can choose what dog they want to walk) then once specific index (dog) is chosen, user walks the dog and it is removed from the Dog list and added to the WalkedDogs list. I hope this isn't to confusing, thanks in advanced!

Answer 1

If you have any queries regarding the program feel free to comment

Program

import java.util.ArrayList;

/*i have created Dogs and WalkedDogs class just for
* demonstration purpose, please change it accordingly*/

class Dogs{
   private String name;

   public Dogs(String name) {
       this.name = name;
   }

   @Override
   public String toString() {
       return name;
   }
}
class WalkedDogs{
   private String name;
  
   public WalkedDogs(String name) {
       this.name = name;
   }
  
   @Override
   public String toString() {
       return name;
   }
}

public class Test{
   public static void main(String[] args) {
       //created list of both classes
       ArrayList<Dogs> dogs = new ArrayList<>();
       ArrayList<WalkedDogs> walkedDogs = new ArrayList<>();
      
       //added items to dogs
       dogs.add(new Dogs("Charlie"));
       dogs.add(new Dogs("Oscar"));
       dogs.add(new Dogs("Max"));
       dogs.add(new Dogs("Olie"));
      
      
       int index = 3; //user want to walk index 3 dog
      
       walked(index, dogs, walkedDogs);//user has completed the walk
      
       //result after walk
       System.out.println("dogs: "+dogs);
       System.out.println("walkedDogs: "+walkedDogs);
   }

   private static void walked(int index, ArrayList<Dogs> dogs, ArrayList<WalkedDogs> walkedDogs) {
      
       String name = dogs.get(3).toString();//getting the items of dogs @index 3
      
       dogs.remove(index);//removing index 3 from dogs
      
       walkedDogs.add(new WalkedDogs(name));//adding it to the walkedDogs
   }
}

Output

<terminated Test (1) [Java Application] C:\Program Files\Java\jre1.8.0_211\bin\javaw.exe (26-Jul-2019, 12:06:40 pm) dogs: [Charlie, Oscar, Max] walkedDogs: [Olie]