How to make a editable list in editor that doesn't need a size parameter

like when I derive a MonoBehaviour

and add a public array to it like:

Code (CSharp):

1. public float[] values;

I can add those values but I also have to set the size, I wonder how I can make a list for the editor, which doesn't need a size parameter.

 

You can't. A list needs a size.

 

Code (CSharp):

1. List<string> listOfStrings = new List<string>();

You use listOfStrings.add("yourStringToAdd") when you want to add an element, and there is a bunch of remove functions also. Make sure the list is instantiated with "new".

 

but other UI components can, you can just add a elments by pressing the plus sign.

 

You'd probably want a custom editor / property drawer for that purpose.
Something like:
https://github.com/cfoulston/Unity-Reorderable-List