Cocoa Programming for OS X: The Big Nerd Ranch Guide

Loading and NSKeyedUnarchiver

Now you will add the ability to load files to your application. Once again, NSDocument has taken care of most of the details for you.

To do the unarchiving, you will use NSKeyedUnarchiver, which has the following handy method:

c​l​a​s​s​ ​f​u​n​c​ ​u​n​a​r​c​h​i​v​e​O​b​j​e​c​t​W​i​t​h​D​a​t​a​(​d​a​t​a​:​ ​N​S​D​a​t​a​)​ ​-​>​ ​A​n​y​O​b​j​e​c​t​?​

In Document.swift, edit your readFromData(_:ofType:error:) method to look like this:

o​v​e​r​r​i​d​e​ ​f​u​n​c​ ​r​e​a​d​F​r​o​m​D​a​t​a​(​d​a​t​a​:​ ​N​S​D​a​t​a​,​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​o​f​T​y​p​e​ ​t​y​p​e​N​a​m​e​:​ ​S​t​r​i​n​g​,​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​e​r​r​o​r​ ​o​u​t​E​r​r​o​r​:​ ...