multithread，GCD，NSURLSession，UITextField，table，UITableViewController，UITextField，keyboard，Dynamic Prototype，Static Cell，UITableViewDataSource，UITableViewDelegate，UIRefreshControl

1. Standford 2015 iOS讀書會
week6
1. Multithreading
2. Table View
彼得潘

2. Main Queue: serial queue，⼀一次從queue取出⼀一個function執⾏行
UI相關動作⼀一定要在main queue執⾏行
Grand Central Dispatch

4. dispatch_async &
dispatch_sync
async: return after task is added to queue
sync: return after task is done

6. serial & concurrent queue
https://developer.apple.com/library/ios/documentation/General/Conceptual/
ConcurrencyProgrammingGuide/OperationQueues/OperationQueues.html

7. demovar number1 = 0
var number2 = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let queue = dispatch_queue_create("Queue", DISPATCH_QUEUE_SERIAL)
dispatch_async(queue, { () -> Void in
for i in 1...10 {
self.number1++
NSThread.sleepForTimeInterval(0.1)
if i == 10 {
println("number1 (self.number1) number2 (self.number2)")
}
}
})
println("dispatch_async1")
dispatch_async(queue, { () -> Void in
for i in 1...10 {
self.number2++
}
})
println("dispatch_async2")
}
dispatch_async1
dispatch_async2
number1 10 number2 0
serial: FIFO

8. demovar number1 = 0
var number2 = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let queue = dispatch_queue_create("Queue", DISPATCH_QUEUE_CONCURRENT)
dispatch_async(queue, { () -> Void in
for i in 1...10 {
self.number1++
NSThread.sleepForTimeInterval(0.1)
if i == 10 {
println("number1 (self.number1) number2 (self.number2)")
}
}
})
println("dispatch_async1")
dispatch_async(queue, { () -> Void in
for i in 1...10 {
self.number2++
}
})
println("dispatch_async2")
}
dispatch_async1
dispatch_async2
number1 10 number2 10

9. demovar number1 = 0
var number2 = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let queue = dispatch_queue_create("Queue", DISPATCH_QUEUE_SERIAL)
dispatch_sync(queue, { () -> Void in
for i in 1...10 {
self.number1++
NSThread.sleepForTimeInterval(0.1)
if i == 10 {
println("number1 (self.number1) number2 (self.number2)")
}
}
})
println("dispatch_sync1")
dispatch_sync(queue, { () -> Void in
for i in 1...10 {
self.number2++
}
})
println("dispatch_sync2")
}
number1 10 number2 0
dispatch_sync1
dispatch_sync2

10. demovar number1 = 0
var number2 = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let queue = dispatch_queue_create("Queue", DISPATCH_QUEUE_CONCURRENT)
dispatch_sync(queue, { () -> Void in
for i in 1...10 {
self.number1++
NSThread.sleepForTimeInterval(0.1)
if i == 10 {
println("number1 (self.number1) number2 (self.number2)")
}
}
})
println("dispatch_sync1")
dispatch_sync(queue, { () -> Void in
for i in 1...10 {
self.number2++
}
})
println("dispatch_sync2")
}
number1 10 number2 0
dispatch_sync1
dispatch_sync2

12. 不在main thread做UI會 ->
Crash ，變慢，奇怪現象

13. NSURLSession
func testDownload() {
let session = NSURLSession(configuration:
NSURLSessionConfiguration.defaultSessionConfiguration())
if let url = NSURL(string: "http://res.cloudinary.com/hrscywv4p/image/upload/
c_limit,f_auto,h_3000,q_80,w_1200/v1/271374/http_s3.amazonaws.com_feather-files-aviary-prod-
us-east-1_f5da8ea5e_2015-03-12_723490bbf79e44a788f5cd2516fefd46_myvzle.jpg") {
let request = NSURLRequest(URL: url)
let task = session.downloadTaskWithRequest(request, completionHandler:
{ (localUrl, response, err) -> Void in
let data = NSData(contentsOfURL: localUrl)
let image = UIImage(data: data!)
let imageView = UIImageView(image: image)
self.view.addSubview(imageView)
println("add image")
})
task.resume()
}
}
圖⽚片過⼀一段時間才出現

14. NSURLSession
func testDownload() {
let session = NSURLSession(configuration:
NSURLSessionConfiguration.defaultSessionConfiguration())
if let url = NSURL(string: "http://res.cloudinary.com/hrscywv4p/image/upload/
c_limit,f_auto,h_3000,q_80,w_1200/v1/271374/http_s3.amazonaws.com_feather-files-aviary-prod-
us-east-1_f5da8ea5e_2015-03-12_723490bbf79e44a788f5cd2516fefd46_myvzle.jpg") {
let request = NSURLRequest(URL: url)
let task = session.downloadTaskWithRequest(request, completionHandler:
{ (localUrl, response, err) -> Void in
let data = NSData(contentsOfURL: localUrl)
let image = UIImage(data: data!)
dispatch_async(dispatch_get_main_queue(), { () -> Void in
let imageView = UIImageView(image: image)
self.view.addSubview(imageView)
})
})
task.resume()
}
}

15. 建⽴立session
let session = NSURLSession.sharedSession()
let session = NSURLSession(configuration:
NSURLSessionConfiguration.defaultSessionConfiguration())
預設會將抓到的資料存在disk，App重新啟動還會存在
若是抓取size太⼤大的資料不會儲存在disk

16. 建⽴立task
let task = session.dataTaskWithURL(url, completionHandler: { (data, response, err) -> Void in
let image = UIImage(data: data!)
dispatch_async(dispatch_get_main_queue(), { () -> Void in
let imageView = UIImageView(image: image)
self.view.addSubview(imageView)
})
})
let task = session.downloadTaskWithRequest(request, completionHandler: { (localUrl,
response, err) -> Void in
let data = NSData(contentsOfURL: localUrl)
let image = UIImage(data: data!)
dispatch_async(dispatch_get_main_queue(), { () -> Void in
let imageView = UIImageView(image: image)
self.view.addSubview(imageView)
})
})

17. private func fetchImage()
{
if let url = imageURL {
spinner?.startAnimating()
let qos = Int(QOS_CLASS_USER_INITIATED.value)
dispatch_async(dispatch_get_global_queue(qos, 0)) { () -> Void in
let imageData = NSData(contentsOfURL: url) // this blocks the thread it is on
dispatch_async(dispatch_get_main_queue()) {
// only do something with this image
// if the url we fetched is the current imageURL we want
// (that might have changed while we were off fetching this one)
if url == self.imageURL { // the variable "url" is capture from above
if imageData != nil {
// this might be a waste of time if our MVC is out of action now
// which it might be if someone hit the Back button
// or otherwise removed us from split view or navigation
controller
// while we were off fetching the image
self.image = UIImage(data: imageData!)
} else {
self.image = nil
}
}
}
}
}
}
closure裡要⽤用self.image，不能只⽤用image
if url == self.imageURL : 判斷是否是⺫⽬目前要顯⽰示的圖⽚片
⽤用weak , unowned 設定self ?

18. table

19. ⼀一⾏行，多⾏行輸⼊入需⽤用UITextView

20. 收鍵盤⽅方法⼤大全
1. 在畫⾯面上加⼊入tap gesture
2. 設定return鍵觸發，經由設定Did End On Exit Event或是
delete的textFieldShouldReturn
⽅方法⼀一: resignFirstResponder
⽅方法⼆二: self.view.endEditing(true)
⽅方法三: 設定keyboardDismissMode
觸發⽅方法:

22. autocapitalizationType: 控制⼤大⼩小寫

23. observer死掉時，會⾃自動被NSNotificationCenter移除
UITableViewController搭配UITextView和UITextField獲得⾃自動scroll魔⼒力
addObserver不會增加observer的retina count

24. inputView: 客製化鍵盤，⽐比⽅方將picker設成鍵盤

27. UITableViewDataSource’s tableView(UITableView, cellForRowAtIndexPath: NSIndexPath)
UITableViewDataSource’s tableView(UITableView, titleForFooterInSection: Int)
UITableViewDataSource’s tableView(UITableView, titleForHeaderInSection: Int)
var tableFooterView: UIView
var tableHeaderView: UIView

29. section: 滑動表格時會固定在畫⾯面上⽅方，參考通訊錄App

31. UITableViewController
view就是tableView
⾃自動連結data source & delegate
如果⾃自⼰己拉的table view要⼿手動連結
static⼀一定要搭配UITableViewController
keyboard auto scroll

32. 不限數量的內容

33. Dynamic Prototypes

34. 內容⾏行數固定的表格
百分之五⼗十的畫⾯面是⾏行數固定的Table

35. Static Cells
只能搭配UITableViewController!

36. 多出來的分隔線？

37. 清除多出來的分隔線:
tableFooterView
tableFooterViewtableHeaderView
加了header才能加footer

38. 超級⽐比⼀一⽐比
@property (nonatomic, retain) UIView *tableHeaderView;
@property (nonatomic, retain) UIView *tableFooterView;
- (UITableViewHeaderFooterView *)headerViewForSection:
(NSInteger)section NS_AVAILABLE_IOS(6_0);
- (UITableViewHeaderFooterView *)footerViewForSection:
(NSInteger)section NS_AVAILABLE_IOS(6_0);
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:
(NSInteger)section;
- (UIView *)tableView:(UITableView *)tableView viewForFooterInSection:
(NSInteger)section;

39. ⽅方法⼀一: UITableViewController做child controller
讓整個畫⾯面只有某部分是table的⽅方法
⽅方法⼆二: UITableView做subview

41. cell reuse: 圖⽚片download問題
圖⽚片完成下載時，cell已被reuse
解法: :
⽅方法⼀一：在cell裡儲存url，⽐比對url確認是否顯⽰示
⽅方法⼆二：定義cell的prepareForReuse，於其中終⽌止下載圖⽚片的動作

44. cell裡設定IBOutlet &
IBAction
IBOutlet連結到cell的程式檔
IBAction連結到controller的程式檔
IBOutlet不能連結到controller的程式檔

45. 在storyboard從cell拉segue時，
可以選selection 或 accessory action (對應Detail Disclosure)

52. //MARK: -
// MARK: - Navigation

53. font: Headline & Body

54. cell點選樣式

55. accessory樣式

56. 動態cell⾼高度
tableView.estimatedRowHeight = tableView.rowHeight
tableView.rowHeight = UITableViewAutomaticDimension

57. 表格的多選
self.tableView.allowsMultipleSelectionDuringEditing = YES;
self.tableView.editing = YES;

58. 表格的delete
func tableView(tableView: UITableView, editingStyleForRowAtIndexPath indexPath:
NSIndexPath) -> UITableViewCellEditingStyle
func tableView(tableView: UITableView, commitEditingStyle editingStyle:
UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath)

59. 表格cell順序調整
func tableView(tableView: UITableView, canMoveRowAtIndexPath indexPath:
NSIndexPath) -> Bool
func tableView(tableView: UITableView, moveRowAtIndexPath sourceIndexPath:
NSIndexPath, toIndexPath destinationIndexPath: NSIndexPath)

60. 下拉更新的refresh
UITableViewController內建UIRefreshControl，
若是⾃自⼰己加⼊入的UITableView必須另外加上UIRefreshControl

61. 下拉更新的refresh
@IBAction func refresh(sender: AnyObject) {
self.refreshControl?.endRefreshing()
}
定義下拉更新觸發的method
endRefreshing: 結束更新，表格回到正常狀態

62. Clear on Appearance
var clearsSelectionOnViewWillAppear: Bool
UITableViewController:
設定⾴頁⾯面appear時，原本被select的cell是否取消選取，勾選表⽰示取消選取
⺫⽬目前在storyboard設定無效，預設會是取消選取，
若想改成不選取，必須另外從程式將clearsSelectionOnViewWillAppear設成false

63. 固定某個元件，
不隨表格scroll
⽅方法⼀一: 將table加到controller的view上
⽅方法⼆二: 將UITableViewController當成child controller，
可利⽤用storyboard的Container View

64. 固定某個元件，
不隨表格scroll
⽅方法三: 將元件加到UITableViewController的view上，
實作scrollViewDidScroll調整元件位置
override func scrollViewDidScroll(scrollView: UIScrollView) {
var frame = self.blueView.frame
frame.origin.y = 10 + scrollView.contentOffset.y
self.blueView.frame = frame
}
override func scrollViewDidScroll(scrollView: UIScrollView) {
var frame = self.blueView.frame
frame.origin.y = 10 + scrollView.contentOffset.y + 64
self.blueView.frame = frame
}
當有透明的nav bar時

65. cell swipe顯⽰示多個button
func tableView(tableView: UITableView, commitEditingStyle editingStyle:
UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath)
func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath:
NSIndexPath) -> [AnyObject]?
http://www.codebuddies.de/2015/03/14/swipeable-cells-in-about-5-minutes-swift/