How can I make a button that imitates DefaultButton and CancelButton?

Question

Both DefaultButton and CancelButton are very convenient, in that they allow one to use FEPrivate`FindAndClickDefaultButton and FEPrivate`FindAndClickCancelButton. Unfortunately DefaultButton doesn't allow me to use custom appearances. How can I get that behavior?

Answer 1

The trick is in the Appearance list. I found this here:

FileNameJoin@{
  PacletFind["CloudObject"][[1]]["Location"],
  "Kernel",
  "Dialogs.m"
  }

The appearances use listed default / hover / pressed / disabled appearances a la this question. There's another appearance option called "ButtonType" which can be set to "Cancel" or "Default" to get the desired behavior. e.g.:

Append[
 FrontEndResource["NotebookTemplatingExpressions", 
  "ButtonDefaultAppearance"],
 "ButtonType" -> "Default"
 ]

I use this, for example, here

This works, of course, because CreateDialog sticks this into a dialog by default:

NotebookEventActions -> {"ReturnKeyDown" :> 
   FE`Evaluate[FEPrivate`FindAndClickDefaultButton[]], {"MenuCommand",
     "EvaluateCells"} :> 
   FE`Evaluate[FEPrivate`FindAndClickDefaultButton[]], {"MenuCommand",
     "HandleShiftReturn"} :> 
   FE`Evaluate[FEPrivate`FindAndClickDefaultButton[]], {"MenuCommand",
     "EvaluateNextCell"} :> 
   FE`Evaluate[FEPrivate`FindAndClickDefaultButton[]], 
  "EscapeKeyDown" :> (FE`Evaluate[
     FEPrivate`FindAndClickCancelButton[]]; DialogReturn[$Failed]), 
  "WindowClose" :> (FE`Evaluate[FEPrivate`FindAndClickCancelButton[]];
     DialogReturn[$Failed])}

And then we can imitate that like so:

CreateDocument[
 {
  Hyperlink["Home Page", 
   "https://www.wolframcloud.com/objects/b3m2a1/home/main.html",
   Appearance ->
    {
     "Default" -> None,
     "ButtonType" -> "Default"
     }
   ],
  Hyperlink["Cancel Page", "https://mathematica.stackexchange.com",
   Appearance ->
    {
     "Default" -> None,
     "ButtonType" -> "Cancel"
     }
   ]
  },
 NotebookEventActions -> {"ReturnKeyDown" :> 
    FE`Evaluate[
     FEPrivate`FindAndClickDefaultButton[]], {"MenuCommand", 
     "EvaluateCells"} :> 
    FE`Evaluate[
     FEPrivate`FindAndClickDefaultButton[]], {"MenuCommand", 
     "HandleShiftReturn"} :> 
    FE`Evaluate[
     FEPrivate`FindAndClickDefaultButton[]], {"MenuCommand", 
     "EvaluateNextCell"} :> 
    FE`Evaluate[FEPrivate`FindAndClickDefaultButton[]], 
   "EscapeKeyDown" :> (FE`Evaluate[
      FEPrivate`FindAndClickCancelButton[]]; DialogReturn[$Failed]), 
   "WindowClose" :> (FE`Evaluate[
      FEPrivate`FindAndClickCancelButton[]]; DialogReturn[$Failed])}
 ]

Where just pressing Enter or Cancel presses those Hyperlinks.