February 2017
Beginner to intermediate
472 pages
9h 53m
Chinese
Content preview from Swift学习手册
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图像和删除
｜
291
图 11-3
：
删除按钮
7.
把下述代码添加到
DocumentViewController
类的
collectionView(_,
cellForItemAtIndexPath:)
方法
中，添加进入删除模式的长按手势识别器：
//
视图控制器处于编辑模式时，这个单元格也处于编辑模式
attachmentCell.editMode = isEditingAttachments
> //
为附件单元格添加长按手势（如果还没有的话）
> let longPressGesture = UILongPressGestureRecognizer(target: self,
> action: "beginEditMode")
> attachmentCell.gestureRecognizers = [longPressGesture]
下面让删除按钮能真正删除附件。我们将添加一个委托协议，当单元格被删除时通知委
托对象。
1.
在
DocumentViewController.swift
文件中添加
AttachmentCellDelegate
协议：
protocol AttachmentCellDelegate {
func attachmentCellWasDeleted(cell: AttachmentCell)
}
2.
在
AttachmentCell
类中添加
delegate
属性：
var delegate : AttachmentCellDelegate? ...
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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.