Java Object Array to JTree

Question

I have a

Class Category 
private Category parent;
private String name;
private ArrayList<Category> categories;
private DefaultMutableTreeNode node;

and an

ArrayList<Category> categories

the ArrayList contains

[0]Categorie #1
   parent = null
   name = asdasd
   ArrayList<Category> categories
      [0]Categorie #2
          parent = #1
          name = asdasddsa
          ArrayList<Category> categories
              [0]Categories #4
                  parent = #2 
                  name = asdasdasd
                  ArrayList<Category> categories = null
      [1]Categorie #3
          parent = #1
          name = asdasdasdasdasd
          ArrayList<Category> categories = null

and i want to create a JTree out of that ArrayList. I tried it with a function that uses itself until the categories ArrayList was null but with this method i couldn't have more than 1 category in the parent categorie.

I created these functions but they don't work.

public void generateNodes(Category category,DefaultMutableTreeNode root){
    ArrayList<Use> usages = category.getUsages();
    for(Use use: usages){
        category.getNode().add(use.getNode());
    }
    if(!category.getCategories().isEmpty()){
        root.add(category.getNode());

        for(Category cat: category.getCategories()){
            generateNodes(cat, category.getNode());
        }

    }else{
        root.add(category.getNode());
    }

}

Oliver Watkins · Accepted Answer · 2013-06-27 15:39:45Z

1

You just need to create a recursive method. Every Category you come across, create a DefaultMutableTreeNode, then add the properties as child nodes. Then recursively call method with the contained Cateogories.

If you want to have more than one category as the root parent, you should make a 'fake' root node, then call this on JTree :

setRootVisible(false);

Its still one tree, but it looks like many. Is that what you meant?

Your code should look something like this :

public void generateNodes(Category categories,DefaultMutableTreeNode root){
        ArrayList<Use> usages = categ.getUsages();
        for(Use use: usages){
            categ.getNode().add(use.getNode());
        }
        if(!categ.getCategories().isEmpty()){
            root.add(categ.getNode());

            for(Category cat: categ.getCategories(){
                generateNodes(categ, root);
            }

        }else{
            root.add(categ.getNode());
        }

}

edited Jun 27, 2013 at 15:39

answered Jun 27, 2013 at 15:14

Oliver Watkins

13.4k40 gold badges135 silver badges254 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

ilikewaffles Over a year ago

i added the functions i created if you want to take a look at them

Oliver Watkins Over a year ago

you need to pass in root into the second method as well : private void generateNodes(ArrayList<Category> categories, root)

Oliver Watkins Over a year ago

the root needs to go into the second message, so that it can get any DefaultMutableTreeNodes that are created in the recursive method

Oliver Watkins Over a year ago

actually you only need the first method, and its signature should be : public void generateNodes(Category categorie,DefaultMutableTreeNode root){

Oliver Watkins Over a year ago

I added code to my original answer. You need ONE method not the TWO. And it should look like my example (I dont have IDE so i cant check it)

|

Collectives™ on Stack Overflow

Java Object Array to JTree

1 Answer 1

7 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

7 Comments

Your Answer

Sign up or log in

Post as a guest

Related