[iOS 多线程 & 网络 - 1.3] - NSOperation

 1 //
 2 //  HVWDownloadImageOperation.h
 3 //  ConcurrentDownloadImageDemo
 4 //
 5 //  Created by hellovoidworld on 15/1/22.
 6 //  Copyright (c) 2015年 hellovoidworld. All rights reserved.
 7 //
 8 
 9 #import <Foundation/Foundation.h>
10 
11 @class HVWDownloadImageOperation;
12 
13 @protocol HVWDownloadImageOperationDelegate <NSObject>
14 
15 /** 代理方法，下载完成之后 */
16 @optional
17 - (void) downloadImageOperation:(HVWDownloadImageOperation *) operation didFinishedDownloadWithImage:(UIImage *) image;
18 
19 @end
20 
21 @interface HVWDownloadImageOperation : NSOperation
22 
23 /** 存储每个图片的url */
24 @property(nonatomic, strong) NSString *url;
25 
26 /** 要显示的cell的index */
27 @property(nonatomic, strong) NSIndexPath *indexPath;
28 
29 /** 代理 */
30 @property(nonatomic, weak) id<HVWDownloadImageOperationDelegate> delegate;
31 
32 @end

 1 //
 2 //  HVWDownloadImageOperation.m
 3 //  ConcurrentDownloadImageDemo
 4 //
 5 //  Created by hellovoidworld on 15/1/22.
 6 //  Copyright (c) 2015年 hellovoidworld. All rights reserved.
 7 //
 8 
 9 #import <UIKit/UIKit.h>
10 #import "HVWDownloadImageOperation.h"
11 
12 
13 @implementation HVWDownloadImageOperation
14 
15 - (void)main {
16     NSLog(@"====下载图片======%@", [NSThread currentThread]);
17    
18     NSURL *url = [NSURL URLWithString:self.url];
19     NSData *data;
20     for (int i=0; i<1; i++) {
21         data = [NSData dataWithContentsOfURL:url];
22     }
23    
24     UIImage *image = [UIImage imageWithData:data];
25    
26     /** 调用代理方法，通知代理下载完成 */
27     if ([self.delegate respondsToSelector:@selector(downloadImageOperation:didFinishedDownloadWithImage:)]) {
28         [self.delegate downloadImageOperation:self didFinishedDownloadWithImage:image];
29     }
30 }
31 
32 @end

 1 //
 2 //  HVWApp.h
 3 //  ConcurrentDownloadImageDemo
 4 //
 5 //  Created by hellovoidworld on 15/1/22.
 6 //  Copyright (c) 2015年 hellovoidworld. All rights reserved.
 7 //
 8 
 9 #import <Foundation/Foundation.h>
10 
11 @interface HVWApp : NSObject
12 
13 /** app名字 */
14 @property(nonatomic, strong) NSString *name;
15 /** app图标url */
16 @property(nonatomic, strong) NSString *icon;
17 /** app的副标题--下载量 */
18 @property(nonatomic, strong) NSString *download;
19 
20 - (instancetype) initWithDictionary:(NSDictionary *) dict;
21 + (instancetype) appWithDictionary:(NSDictionary *) dict;
22 
23 @end

  1 //
  2 //  ViewController.m
  3 //  ConcurrentDownloadImageDemo
  4 //
  5 //  Created by hellovoidworld on 15/1/22.
  6 //  Copyright (c) 2015年 hellovoidworld. All rights reserved.
  7 //
  8 
  9 #import "ViewController.h"
 10 #import "HVWApp.h"
 11 #import "HVWDownloadImageOperation.h"
 12 
 13 @interface ViewController () <UITableViewDataSource, UITableViewDelegate, HVWDownloadImageOperationDelegate>
 14 
 15 /** 所有app数据 */
 16 @property(nonatomic, strong) NSArray *apps;
 17 
 18 /** 任务队列 */
 19 @property(nonatomic, strong) NSOperationQueue *queue;
 20 
 21 /** 所有任务 */
 22 @property(nonatomic, strong) NSMutableDictionary *operations;
 23 
 24 /** 所有图片 */
 25 @property(nonatomic, strong) NSMutableDictionary *images;
 26 
 27 @end
 28 
 29 @implementation ViewController
 30 
 31 /** 加载plist文件，读取数据到模型，存储到数组中 */
 32 - (NSArray *)apps {
 33     if (nil == _apps) {
 34         NSArray *dictArray = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"apps.plist" ofType:nil]];
 35        
 36         NSMutableArray *appArray = [NSMutableArray array];
 37         for (NSDictionary *dict in dictArray) {
 38             HVWApp *app = [HVWApp appWithDictionary:dict];
 39             [appArray addObject:app];
 40         }
 41         _apps = appArray;
 42     }
 43     return _apps;
 44 }
 45 
 46 - (NSOperationQueue *)queue {
 47     if (_queue == nil ) {
 48         _queue = [[NSOperationQueue alloc] init];
 49         _queue.maxConcurrentOperationCount = 3;
 50     }
 51     return _queue;
 52 }
 53 
 54 - (NSMutableDictionary *)operations {
 55     if (nil == _operations) {
 56         _operations = [NSMutableDictionary dictionary];
 57     }
 58     return _operations;
 59 }
 60 
 61 - (NSMutableDictionary *)images {
 62     if (nil == _images) {
 63         _images = [NSMutableDictionary dictionary];
 64     }
 65     return _images;
 66 }
 67 
 68 - (void)viewDidLoad {
 69     [super viewDidLoad];
 70     // Do any additional setup after loading the view, typically from a nib.
 71 }
 72 
 73 - (void)didReceiveMemoryWarning {
 74     [super didReceiveMemoryWarning];
 75     // Dispose of any resources that can be recreated.
 76 }
 77 
 78 #pragma mark - tableViewDatasource
 79 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
 80     return 1;
 81 }
 82 
 83 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
 84     return self.apps.count;
 85 }
 86 
 87 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
 88     static NSString *ID = @"AppCell";
 89     UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
 90    
 91     if (nil == cell) {
 92         cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:ID];
 93     }
 94    
 95     HVWApp *app = self.apps[indexPath.row];
 96     cell.textLabel.text = app.name;
 97     cell.detailTextLabel.text = app.download;
 98    
 99     // 占位图片
100     cell.imageView.image = [UIImage imageNamed:@"a9ec8a13632762d0092abc3ca2ec08fa513dc619"];
101    
102     // 如果没有图片，准备开启线程下载图片
103     UIImage *image = self.images[app.icon];
104    
105     if (image) {
106         // 如果图片存在，不需要重复下载，直接设置图片
107         cell.imageView.image = image;
108     } else {
109        
110         // 如果图片不存在，看看是不是正在下载
111         HVWDownloadImageOperation *operation = self.operations[app.icon];
112        
113         if (operation) {
114             // 如果图片正在下载，不必要开启线的线程再进行下载
115         } else {
116            
117             // 没有在下载，创建一个新的任务进行下载
118             operation = [[HVWDownloadImageOperation alloc] init];
119             // 设置代理
120             operation.delegate = self;
121             // 传送url
122             operation.url = app.icon;
123             // 记录indexPath
124             operation.indexPath = indexPath;
125            
126             [self.queue addOperation:operation];
127            
128             // 记录正在下载的任务
129             [self.operations setObject:operation forKey:operation.url];
130         }
131     }
132    
133     return cell;
134 }
135 
136 #pragma mark - HVWDownloadImageOperationDelegate
137 /** 代理方法，图片下载完成后，显示到cell上 */
138 - (void)downloadImageOperation:(HVWDownloadImageOperation *)operation didFinishedDownloadWithImage:(UIImage *)image {
139     UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:operation.indexPath];
140     cell.imageView.image = image;
141     [self.tableView reloadRowsAtIndexPaths:@[operation.indexPath] withRowAnimation:UITableViewRowAnimationNone];
142    
143     // 存储图片到内存
144     if (image) {
145         [self.images setObject:image forKey:operation.url];
146     }
147    
148     NSLog(@"已经下载的图片数==========>%d", self.images.count);
149 }
150 
151 @end