多线程开发之二NSOperation

1 #import <UIKit/UIKit.h>2 3 @interface ViewController : UITableViewController4 @PRoperty (copy, nonatomic) NSArray *arrSampleName;5 6 - (instancetype)initWithSampleNameArray:(NSArray *)arrSampleName;7 8 @end 

 1 #import "ViewController.h" 2 #import "FirstSampleViewController.h" 3 #import "SecondSampleViewController.h" 4  5 @interface ViewController () 6 - (void)layoutUI; 7 @end 8  9 @implementation ViewController10 - (void)viewDidLoad {11     [super viewDidLoad];12     13     [self layoutUI];14 }15 16 - (void)didReceiveMemoryWarning {17     [super didReceiveMemoryWarning];18     // Dispose of any resources that can be recreated.19 }20 21 - (instancetype)initWithSampleNameArray:(NSArray *)arrSampleName {22     if (self = [super initWithStyle:UITableViewStyleGrouped]) {23         self.navigationItem.title = @"多线程开发之二 NSOperation";24         self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"返回首页" style:UIBarButtonItemStylePlain target:nil action:nil];25         26         _arrSampleName = arrSampleName;27     }28     return self;29 }30 31 - (void)layoutUI {32 }33 34 #pragma mark - UITableViewController相关方法重写35 - (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {36     return 0.1;37 }38 39 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {40     return 1;41 }42 43 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {44     return [_arrSampleName count];45 }46 47 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {48     static NSString *cellIdentifier = @"cell";49     UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];50     if (!cell) {51         cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];52     }53     cell.textLabel.text = _arrSampleName[indexPath.row];54     return cell;55 }56 57 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {58     switch (indexPath.row) {59         case 0: {60             FirstSampleViewController *firstSampleVC = [FirstSampleViewController new];61             [self.navigationController pushViewController:firstSampleVC animated:YES];62             break;63         }64         case 1: {65             SecondSampleViewController *secondSampleVC = [SecondSampleViewController new];66             [self.navigationController pushViewController:secondSampleVC animated:YES];67             break;68         }69         default:70             break;71     }72 }73 74 @end 

 1 #import <UIKit/UIKit.h> 2  3 @interface UIImage (RescaleImage) 4 /** 5  *  根据宽高大小，获取对应的缩放图片 6  * 7  *  @param size 宽高大小 8  * 9  *  @return 对应的缩放图片10  */11 - (UIImage *)rescaleImageToSize:(CGSize)size;12 13 @end 

 1 #import "UIImage+RescaleImage.h" 2  3 @implementation UIImage (RescaleImage) 4  5 - (UIImage *)rescaleImageToSize:(CGSize)size { 6     CGRect rect = CGRectMake(0.0, 0.0, size.width, size.height); 7      8     UIGraphicsBeginImageContext(rect.size); 9     [self drawInRect:rect];10     UIImage *imgScale = UIGraphicsGetImageFromCurrentImageContext();11     UIGraphicsEndImageContext();12     13     return imgScale;14 }15 16 @end 

1 #import <Foundation/Foundation.h>2 3 @interface Common : NSObject4 + (NSURL *)randomImageURL;5 6 @end 

 1 #import "Common.h" 2  3 @implementation Common 4  5 + (NSURL *)randomImageURL { 6     NSUInteger randomVal = (arc4random() % 20) + 1; //1-20的随机数 7     NSString *randomValStr = [NSString stringWithFormat:@"%lu", (unsigned long)randomVal]; 8     if (randomVal < 10) { 9         randomValStr = [@"0" stringByAppendingString:randomValStr];10     }11     12     NSString *imageURLStr = [NSString stringWithFormat:@"http://images.apple.com/v/watch/e/apple-watch/images/collection_%@_large.jpg", randomValStr];13     return [NSURL URLWithString:imageURLStr];14 }15 16 @end 

1 #import <UIKit/UIKit.h>2 3 @interface FirstSampleViewController : UIViewController4 @property (assign, nonatomic) CGSize rescaleImageSize;5 6 @property (strong, nonatomic) IBOutlet UIImageView *imgV;7 @property (strong, nonatomic) IBOutlet UIButton *btnLoadImage;8 9 @end 

 1 #import "FirstSampleViewController.h" 2 #import "UIImage+RescaleImage.h" 3 #import "Common.h" 4  5 @interface FirstSampleViewController () 6 - (void)layoutUI; 7 - (void)updateImage:(NSData *)imageData; 8 - (void)loadImageFromNetwork; 9 @end10 11 @implementation FirstSampleViewController12 13 - (void)viewDidLoad {14     [super viewDidLoad];15     16     [self layoutUI];17 }18 19 - (void)didReceiveMemoryWarning {20     [super didReceiveMemoryWarning];21     // Dispose of any resources that can be recreated.22 }23 24 - (void)dealloc {25     _imgV.image = nil;26 }27 28 - (void)layoutUI {29     CGFloat width = [[UIScreen mainScreen] bounds].size.width; //bounds 返回整个屏幕大小；applicationFrame 返回去除状态栏后的屏幕大小30     CGFloat height = width * 438.0 / 366.0;31     const CGFloat percentVal = 3.0 / 4.0; //以屏幕宽度的3/4比例显示32     _rescaleImageSize = CGSizeMake(width * percentVal, height * percentVal);33     34     //NSString *path = [[NSBundle mainBundle] pathForResource:@"PictureNo@2x" ofType:@"png"];35     //_imgV.image = [UIImage imageWithContentsOfFile:path];36     37     _btnLoadImage.tintColor = [UIColor darkGrayColor];38     _btnLoadImage.layer.masksToBounds = YES;39     _btnLoadImage.layer.cornerRadius = 10.0;40     _btnLoadImage.layer.borderColor = [UIColor grayColor].CGColor;41     _btnLoadImage.layer.borderWidth = 1.0;42 }43 44 - (void)updateImage:(NSData *)imageData {45     UIImage *img = [UIImage imageWithData:imageData];46     _imgV.image = [img rescaleImageToSize:_rescaleImageSize];47 }48 49 - (void)loadImageFromNetwork {50     NSURL *url = [Common randomImageURL];51     NSData *data = [NSData dataWithContentsOfURL:url];52     53     //mainQueue 是 UI 主线程，调用主线程队列的方法进行操作54     [[NSOperationQueue mainQueue] addOperationWithBlock:^{55         [self updateImage:data];56     }];57 }58 59 - (IBAction)loadImage:(id)sender {60     //方法一：使用 NSInvocationOperation61 //    NSInvocationOperation *invocationOperation = [[NSInvocationOperation alloc]62 //                                                  initWithTarget:self63 //                                                  selector:@selector(loadImageFromNetwork)64 //                                                  object:nil];65 //    NSOperationQueue *operationQueue = [NSOperationQueue new]; //操作队列66 //    [operationQueue addOperation:invocationOperation];67 68     69     //方法二：使用 NSBlockOperation70     NSBlockOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:^{71         [self loadImageFromNetwork];72     }];73     [blockOperation addExecutionBlock:^{ //还可以为 blockOperation 添加代码块；多个代码块会被分到多个线程去执行，存在两个代码块被分配到同一个线程执行的情况74         NSLog(@"代码块");75     }];76     [blockOperation addExecutionBlock:[blockOperation executionBlocks][1]]; //这里可以调用他的 executionBlocks 获取到添加的代码块数组；上面打印的内容「代码块」会被执行两次77     78     [blockOperation setCompletionBlock:^{79         NSLog(@"所有代码块操作执行完毕后（无论已取消还是已完成），做一些事情，只执行一次");80     }];81     82     //[blockOperation start]; //使用 start 方法，则此操作在主线程中执行；一般不这样操作，而是添加到操作队列中83     NSOperationQueue *operationQueue = [NSOperationQueue new]; //操作队列84     [operationQueue addOperation:blockOperation]; //添加到操作队列，这时队列会开启一个线程去执行此操作；一个线程可以执行多个操作85     86     //方法三：直接使用 NSOperationQueue87 //    NSOperationQueue *operationQueue = [NSOperationQueue new]; //操作队列88 //    [operationQueue addOperationWithBlock:^{89 //        [self loadImageFromNetwork];90 //    }];91 }92 93 @end 

 1 <?xml version="1.0" encoding="UTF-8" standalone="no"?> 2 <document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="7706" systemVersion="14E46" targetRuntime="iOS.CocoaTouch" propertyaccessControl="none" useAutolayout="YES" useTraitCollections="YES"> 3     <dependencies> 4         <deployment identifier="iOS"/> 5         <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="7703"/> 6     </dependencies> 7     <objects> 8         <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner" customClass="FirstSampleViewController"> 9             <connections>10                 <outlet property="btnLoadImage" destination="sLs-f1-Gzc" id="kX8-J0-v0V"/>11                 <outlet property="imgV" destination="4Qp-uk-KAb" id="RM3-Ha-glh"/>12                 <outlet property="view" destination="i5M-Pr-FkT" id="sfx-zR-JGt"/>13             </connections>14         </placeholder>15         <placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/>16         <view clearsContextBeforeDrawing="NO" contentMode="scaleToFill" id="i5M-Pr-FkT">17             <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>18             <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>19             <subviews>20                 <imageView userInteractionEnabled="NO" contentMode="scaleToFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" image="PictureNo.png" translatesAutoresizingMaskIntoConstraints="NO" id="4Qp-uk-KAb">21                     <rect key="frame" x="205" y="225" width="190" height="150"/>22                     <constraints>23                         <constraint firstAttribute="height" constant="150" id="Sip-Wd-idU"/>24                         <constraint firstAttribute="height" constant="150" id="VwM-i1-atB"/>25                         <constraint firstAttribute="width" constant="190" id="mUh-Bu-tUd"/>26                         <constraint firstAttribute="width" constant="190" id="mdJ-1c-QFa"/>27                         <constraint firstAttribute="width" constant="190" id="sVS-bU-Ty9"/>28                         <constraint firstAttribute="height" constant="150" id="uMG-oN-J56"/>29                         <constraint firstAttribute="height" constant="150" id="vws-Qw-UrB"/>30                     </constraints>31                     <variation key="default">32                         <mask key="constraints">33                             <exclude reference="SIp-Wd-idU"/>34                             <exclude reference="VwM-i1-atB"/>35                             <exclude reference="mUh-Bu-tUd"/>36                             <exclude reference="mdJ-1c-QFa"/>37                             <exclude reference="sVS-bU-Ty9"/>38                             <exclude reference="uMG-oN-J56"/>39                             <exclude reference="vws-Qw-UrB"/>40                         </mask>41                     </variation>42                 </imageView>43                 <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="sLs-f1-Gzc">44                     <rect key="frame" x="230" y="500" width="140" height="50"/>45                     <constraints>46                         <constraint firstAttribute="width" constant="140" id="1jv-9K-mdH"/>47                         <constraint firstAttribute="height" constant="50" id="Q2w-vR-9ac"/>48                     </constraints>49                     <state key="normal" title="加载网络图片">50                         <color key="titleShadowColor" white="0.5" alpha="1" colorSpace="calibratedWhite"/>51                     </state>52                     <connections>53                         <action selector="loadImage:" destination="-1" eventType="touchUpInside" id="fdy-Ln-5oS"/>54                     </connections>55                 </button>56             </subviews>57             <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>58             <constraints>59                 <constraint firstItem="4Qp-uk-KAb" firstAttribute="leading" secondItem="i5M-Pr-FkT" secondAttribute="leading" constant="205" id="2a2-mS-WFa"/>60                 <constraint firstItem="sLs-f1-Gzc" firstAttribute="top" secondItem="i5M-Pr-FkT" secondAttribute="top" id="ES4-wl-RBz"/>61                 <constraint firstItem="4Qp-uk-KAb" firstAttribute="centerY" secondItem="i5M-Pr-FkT" secondAttribute="centerY" id="MUJ-WA-sUf"/>62                 <constraint firstItem="4Qp-uk-KAb" firstAttribute="centerX" secondItem="sLs-f1-Gzc" secondAttribute="centerX" id="Q8a-1k-DzJ"/>63                 <constraint firstAttribute="bottom" secondItem="4Qp-uk-KAb" secondAttribute="bottom" constant="71" id="V0a-9y-Dwa"/>64                 <constraint firstAttribute="bottom" secondItem="sLs-f1-Gzc" secondAttribute="bottom" constant="50" id="VMG-CV-eeq"/>65                 <constraint firstItem="4Qp-uk-KAb" firstAttribute="top" secondItem="i5M-Pr-FkT" secondAttribute="top" constant="-71" id="gqW-Wq-4Zv"/>66                 <constraint firstItem="sLs-f1-Gzc" firstAttribute="centerX" secondItem="i5M-Pr-FkT" secondAttribute="centerX" id="kNf-6d-EJ8"/>67             </constraints>68             <variation key="default">69                 <mask key="constraints">70                     <exclude reference="2a2-mS-WFa"/>71                     <exclude reference="V0a-9y-Dwa"/>72                     <exclude reference="gqW-Wq-4Zv"/>73                     <exclude reference="ES4-wl-RBz"/>74                 </mask>75             </variation>76         </view>77     </objects>78     <resources>79         <image name="PictureNo.png" width="190" height="150"/>80     </resources>81 </document> 

1 #import <UIKit/UIKit.h>2 3 @interface SecondSampleViewController : UIViewController4 @property (assign, nonatomic) CGSize rescaleImageSize;5 @property (strong, nonatomic) NSMutableArray *mArrImageView;6 7 @property (strong, nonatomic) IBOutlet UIButton *btnLoadImage;8 9 @end 

  1 #import "SecondSampleViewController.h"  2 #import "UIImage+RescaleImage.h"  3 #import "Common.h"  4   5 #define kRowCount 4  6 #define kColumnCount 3  7 #define kCellSpacing 10.0  8   9 @interface SecondSampleViewController () 10 - (void)layoutUI; 11 - (void)updateImage:(NSData *)imageData withImageIndex:(NSInteger)imageIndex; 12 -(NSData *)requestData:(NSInteger)imageIndex; 13 - (void)loadImageFromNetwork:(NSInteger)imageIndex; 14 @end 15  16 @implementation SecondSampleViewController 17  18 - (void)viewDidLoad { 19     [super viewDidLoad]; 20      21     [self layoutUI]; 22 } 23  24 - (void)didReceiveMemoryWarning { 25     [super didReceiveMemoryWarning]; 26     // Dispose of any resources that can be recreated. 27 } 28  29 - (void)dealloc { 30     _mArrImageView = nil; 31 } 32  33 - (void)layoutUI { 34     CGFloat width = ([[UIScreen mainScreen] bounds].size.width - ((kColumnCount + 1) * kCellSpacing)) / kColumnCount; 35     _rescaleImageSize = CGSizeMake(width, width); 36      37     CGFloat heightOfStatusAndNav = 20.0 + 44.0; 38     NSString *path = [[NSBundle mainBundle] pathForResource:@"PictureNo@2x" ofType:@"png"]; 39     UIImage *img = [UIImage imageWithContentsOfFile:path]; 40     _mArrImageView = [NSMutableArray arrayWithCapacity:kRowCount * kColumnCount]; 41     //初始化多个图片视图 42     for (NSUInteger i=0; i<kRowCount; i++) { 43         for (NSUInteger j=0; j<kColumnCount; j++) { 44             UIImageView *imgV = [[UIImageView alloc] initWithFrame: 45                                  CGRectMake(_rescaleImageSize.width * j + kCellSpacing * (j+1), 46                                             _rescaleImageSize.height * i + kCellSpacing * (i+1) + heightOfStatusAndNav, 47                                             _rescaleImageSize.width, 48                                             _rescaleImageSize.height)]; 49             imgV.image = img; 50             [self.view addSubview:imgV]; 51             [_mArrImageView addObject:imgV]; 52         } 53     } 54      55     _btnLoadImage.tintColor = [UIColor darkGrayColor]; 56     _btnLoadImage.layer.masksToBounds = YES; 57     _btnLoadImage.layer.cornerRadius = 10.0; 58     _btnLoadImage.layer.borderColor = [UIColor grayColor].CGColor; 59     _btnLoadImage.layer.borderWidth = 1.0; 60 } 61  62 - (void)updateImage:(NSData *)imageData withImageIndex:(NSInteger)imageIndex { 63     UIImage *img = [UIImage imageWithData:imageData]; 64     UIImageView *imgVCurrent = _mArrImageView[imageIndex]; 65     imgVCurrent.image = [img rescaleImageToSize:_rescaleImageSize]; 66 } 67  68 -(NSData *)requestData:(NSInteger)imageIndex { 69     //对于多线程操作，建议把线程操作放到 @autoreleasepool 中 70     @autoreleasepool { 71         NSURL *url = [Common randomImageURL]; 72         NSData *data = [NSData dataWithContentsOfURL:url]; 73         return data; 74     } 75 } 76  77 - (void)loadImageFromNetwork:(NSInteger)imageIndex { 78     /* 79      对比之前 NSThread 加载图片，你会发现核心代码简化了不少，有两点值得提的： 80      （1）使用 NSBlockOperation 方法，所有的操作不必单独定义方法，同时解决了只能传递一个参数的问题。类似的操作，例如：调用主线程队列的 addOperationWithBlock: 方法进行 UI 更新，不用再定义一个参数实体类来进行参数传递（之前必须定义一个 KMImageData 解决只能传递一个参数的问题）。 81      （2）使用 NSOperation 进行多线程开发可以设置最大并发操作数，有效的对操作进行控制（如 Demo 的代码设置最大并发操作数为5，则图片最多是五个一次加载的）。 82      */ 83     NSLog(@"Current thread:%@", [NSThread currentThread]); 84      85     //mainQueue 是 UI 主线程，调用主线程队列的方法进行操作 86     [[NSOperationQueue mainQueue] addOperationWithBlock:^{ 87         [self updateImage:[self requestData:imageIndex] withImageIndex:imageIndex]; 88     }]; 89 } 90  91 - (IBAction)loadImage:(id)sender { 92     NSOperationQueue *operationQueue = [NSOperationQueue new]; 93     operationQueue.maxConcurrentOperationCount = 5; //设置最大并发操作数 94      95     NSUInteger len = kRowCount * kColumnCount; 96     NSBlockOperation *lastBlockOperation = [NSBlockOperation blockOperationWithBlock:^{ 97         [self loadImageFromNetwork:len - 1]; 98     }]; 99     100     for (NSUInteger i=0; i<len - 1; i++) {101         NSBlockOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:^{102             [self loadImageFromNetwork:i];103         }];104         105         //实现控制「操作执行顺序」，例如：控制最后一个操作第一个执行，这里设置操作的依赖关系为：最后一张图片加载操作完成后才执行106         //PS：注意请勿进行循环依赖，否则循环依赖相关的操作是不会被执行的107         //这里添加依赖关系；其相对应的移除方法：- (void)removeDependency:(NSOperation *)op;108         [blockOperation addDependency:lastBlockOperation];109         110         //另外添加操作对象实例数组的方法：- (void)addOperations:(NSArray *)ops waitUntilFinished:(BOOL)wait;111         [operationQueue addOperation:blockOperation];112     }113     114     [operationQueue addOperation:lastBlockOperation];115     116     /*117     lastBlockOperation.queuePriority = NSOperationQueuePriorityVeryHigh; //在某个操作队列中的队列优先级；这样可以提高他被优先加载的机率，但是他也未必就第一个加载；所以要实现控制「操作执行顺序」，就得用设置操作的依赖关系的方式118     119     typedef enum : NSInteger {120         NSOperationQueuePriorityVeryLow = -8,121         NSOperationQueuePriorityLow = -4,122         NSOperationQueuePriorityNormal = 0,123         NSOperationQueuePriorityHigh = 4,124         NSOperationQueuePriorityVeryHigh = 8125     } NSOperationQueuePriority;126      */127 }128 129 @end 

 1 <?xml version="1.0" encoding="UTF-8" standalone="no"?> 2 <document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="7706" systemVersion="14E46" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES"> 3     <dependencies> 4         <deployment identifier="iOS"/> 5         <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="7703"/> 6     </dependencies> 7     <objects> 8         <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner" customClass="SecondSampleViewController"> 9             <connections>10                 <outlet property="btnLoadImage" destination="F5h-ZI-gGL" id="I40-e2-bAa"/>11                 <outlet property="view" destination="i5M-Pr-FkT" id="sfx-zR-JGt"/>12             </connections>13         </placeholder>14         <placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/>15         <view clearsContextBeforeDrawing="NO" contentMode="scaleToFill" id="i5M-Pr-FkT">16             <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>17             <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>18             <subviews>19                 <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="F5h-ZI-gGL">20                     <rect key="frame" x="230" y="530" width="140" height="50"/>21                     <constraints>22                         <constraint firstAttribute="height" constant="50" id="HWd-Xc-Wk7"/>23                         <constraint firstAttribute="width" constant="140" id="vrH-qE-PNK"/>24                     </constraints>25                     <state key="normal" title="加载网络图片">26                         <color key="titleShadowColor" white="0.5" alpha="1" colorSpace="calibratedWhite"/>27                     </state>28                     <connections>29                         <action selector="loadImage:" destination="-1" eventType="touchUpInside" id="Hgw-q8-lHy"/>30                     </connections>31                 </button>32             </subviews>33             <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>34             <constraints>35                 <constraint firstAttribute="bottom" secondItem="F5h-ZI-gGL" secondAttribute="bottom" constant="20" id="jPY-fY-9XJ"/>36                 <constraint firstAttribute="centerX" secondItem="F5h-ZI-gGL" secondAttribute="centerX" id="rH1-sV-pST"/>37             </constraints>38         </view>39     </objects>40 </document> 

1 #import <UIKit/UIKit.h>2 3 @interface AppDelegate : UIResponder <UIApplicationDelegate>4 5 @property (strong, nonatomic) UIWindow *window;6 @property (strong, nonatomic) UINavigationController *navigationController;7 8 @end 

 1 #import "AppDelegate.h" 2 #import "ViewController.h" 3  4 @interface AppDelegate () 5  6 @end 7  8 @implementation AppDelegate 9 10 11 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {12     _window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];13     ViewController *viewController = [[ViewController alloc] initWithSampleNameArray:@[@"请求单张网络图片（解决线程阻塞）", @"请求多张网络图片（多个线程并发）"]];14     _navigationController = [[UINavigationController alloc] initWithRootViewController:viewController];15     _window.rootViewController = _navigationController;16     //[_window addSubview:_navigationController.view]; //当_window.rootViewController关联时，这一句可有可无17     [_window makeKeyAndVisible];18     return YES;19 }20 21 - (void)applicationWillResignActive:(UIApplication *)application {22 }23 24 - (void)applicationDidEnterBackground:(UIApplication *)application {25 }26 27 - (void)applicationWillEnterForeground:(UIApplication *)application {28 }29 30 - (void)applicationDidBecomeActive:(UIApplication *)application {31 }32 33 - (void)applicationWillTerminate:(UIApplication *)application {34 }35 36 @end 

 1 2015-08-28 00:26:36.878 NSOperationDemo[4228:48976] 代码块 2 2015-08-28 00:26:36.878 NSOperationDemo[4228:48977] 代码块 3 2015-08-28 00:26:37.366 NSOperationDemo[4228:48976] 所有代码块操作执行完毕后（无论已取消还是已完成），做一些事情，只执行一次 4  5 2015-08-28 00:26:42.505 NSOperationDemo[4228:48860] Current thread:<NSThread: 0x7fbd1bd335b0>{number = 3, name = (null)} 6 2015-08-28 00:26:42.506 NSOperationDemo[4228:48978] Current thread:<NSThread: 0x7fbd1be0ad90>{number = 4, name = (null)} 7 2015-08-28 00:26:42.507 NSOperationDemo[4228:48990] Current thread:<NSThread: 0x7fbd1e047390>{number = 5, name = (null)} 8 2015-08-28 00:26:42.507 NSOperationDemo[4228:48990] Current thread:<NSThread: 0x7fbd1e047390>{number = 5, name = (null)} 9 2015-08-28 00:26:42.507 NSOperationDemo[4228:48978] Current thread:<NSThread: 0x7fbd1be0ad90>{number = 4, name = (null)}10 2015-08-28 00:26:42.507 NSOperationDemo[4228:49025] Current thread:<NSThread: 0x7fbd1be07c70>{number = 6, name = (null)}11 2015-08-28 00:26:42.508 NSOperationDemo[4228:48978] Current thread:<NSThread: 0x7fbd1be0ad90>{number = 4, name = (null)}12 2015-08-28 00:26:42.508 NSOperationDemo[4228:49025] Current thread:<NSThread: 0x7fbd1be07c70>{number = 6, name = (null)}13 2015-08-28 00:26:42.508 NSOperationDemo[4228:48978] Current thread:<NSThread: 0x7fbd1be0ad90>{number = 4, name = (null)}14 2015-08-28 00:26:42.508 NSOperationDemo[4228:48990] Current thread:<NSThread: 0x7fbd1e047390>{number = 5, name = (null)}15 2015-08-28 00:26:42.508 NSOperationDemo[4228:48976] Current thread:<NSThread: 0x7fbd1e0335f0>{number = 7, name = (null)}16 2015-08-28 00:26:42.508 NSOperationDemo[4228:48978] Current thread:<NSThread: 0x7fbd1be0ad90>{number = 4, name = (null)}