Convert ArrayList<ArrayList<Object>> to Object[][]

Question

I would like to populate a JTable with the cnstructor like this :

new JTable(datas, columns);

so I need an Object[] for the columns and a Object[][] for the datas. The problem is when I try to get the datas.

In one of my method I work with an ArrayList<ArrayList<Object>> and I would like to cast it to an Object[][].

Here's a sample of my code :

ArrayList<ArrayList<Object>> datas = new ArrayList<ArrayList<Object>>();

for (Map.Entry<Integer, JSObject> entry : params.entrySet()) {
    datas.add(entry.getValue().getValues()); // getValues returns an ArrayList<Object>
}

return new datas.toArray(); //  not seems to work

I saw in this question Convert ArrayList<Object[]> to Object[][] some idea, but I'm not sure about the result.

Thanks in advance !

Also, return new datas.toArray(); is not a valid statement (new should probably be removed) — user180100
– user180100, Commented Mar 30, 2014 at 11:53
because I get params from another object where I prefere to use ArrayList but I try this solution, and let you know what comes from it... And yes the new had nothing to do here, thanks — nobe4
– nobe4, Commented Mar 30, 2014 at 11:54

Keppil · Accepted Answer · 2014-03-30 11:55:46Z

4

Can't you just change the type of datas to an ArrayList<Object[]>, and use toArray() each time you add an element:

ArrayList<Object[]> datas = new ArrayList<Object[]>();
for (Map.Entry<Integer, JSObject> entry : params.entrySet()) {
    datas.add(entry.getValue().getValues().toArray());
}
return datas.toArray(new Object[][]{});

answered Mar 30, 2014 at 11:55

Keppil

46.3k9 gold badges101 silver badges121 bronze badges

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

2 Comments

nobe4 Over a year ago

I have to add (Object[][]) to cast the return statment but it seems to work, I test it and let you know

Keppil Over a year ago

@Nobe4: True, used the other toArray() instead to prevent the need to cast.

Collectives™ on Stack Overflow

Convert ArrayList<ArrayList<Object>> to Object[][]

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related