Unity - Adding more functionality to a List<T> Inspector

Question

Let's say I have the following code:

public List<Armor> armors = new List<Armor> {
    new Armor() { name = "Black set",         folder = "black_set"},
    new Armor() { name = "Conquistador",      folder = "conquistador"},
    new Armor() { name = "Crusader",          folder = "crusader"},
    new Armor() { name = "Gothic Plate",      folder = "gothic_plate"},
    new Armor() { name = "K.D.",              folder = "kd"},
    new Armor() { name = "Lorica segmentata", folder = "lorica_segmentata"},
    new Armor() { name = "Rusty",             folder = "rusty"},
    new Armor() { name = "Spartan",           folder = "spartan"}
};

This appears in the editor like this:

While this is acceptable, there are a couple features I am missing: Lets take for instance the Sorting Layer list:

Here there are 2 features that I would like:

1. The ability to reorder elements on the editor
2. The ability to add more elements using + or -

Is there any way to add this functionality into my List?

Answer 1

You want to use Rotorz open-source Reorderable List to save yourself some time. This is the library I use to do exactly what you want. It makes Lists Reorderable in the inspector like the Sorting Layers and more without you having to write more custom inspector code then you need. Here's the library.

Answer 2

Being specific I would say

public ReorderableList(SerializedObject serializedObject, SerializedProperty elements, bool draggable, bool displayHeader, bool displayAddButton, bool displayRemoveButton);

Here is the tutorial to this. As it is always great to use which domain owners provide, so this Rotorz UI extensions are also good but I would recommend native library which Unity provides inside UnityEditorInternal dll