February 2017
Beginner to intermediate
472 pages
9h 53m
Chinese
Content preview from Swift学习手册
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
138
｜
第
6
章
6.2.1
在集合视图单元格中显示图标
显示附件时，我们要使用某种图片表示它们。此外，我们还会在刚刚创建的标注中显示
各个附件的扩展名。
附件使用
NSFileWrapper
对象表示，我们需要从中获取附件的图像表述。因此，我们要
扩展
NSFileWrapper
类，添加一个方法，返回图像。我们还需要获取文件扩展名的方式
才能显示。
我们讨论的是两种“
extension
”：
译注
1
一种是文件的扩展名（例如，文件名
Text.
rtf
中的“
rtf
”部分），另一种是
Swift
的扩展，在第
3
章介绍过。不要弄混了！我
们经常会混淆。
1.
打开
Document.swift
。
2.
在文件的顶部、
Document
类外部添加下述扩展：
extension NSFileWrapper {
dynamic var fileExtension : String? {
return self.preferredFilename?
.componentsSeparatedByString(".").last
}
dynamic var thumbnailImage : NSImage {
if let fileExtension = self.fileExtension {
return NSWorkspace.sharedWorkspace()
.iconForFileType(fileExtension)
} else {
return ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.