iOS开发多线程篇—线程间的通信

一、简单说明

线程间通信：在1个进程中，线程往往不是孤立存在的，多个线程之间需要经常进行通信

线程间通信的体现

1个线程传递数据给另1个线程

在1个线程中执行完特定任务后，转到另1个线程继续执行任务

线程间通信常用方法

- (void)performSelectorOnMainThread:(SEL)aSelector withObject:(id)arg waitUntilDone:(BOOL)wait;

- (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(id)arg waitUntilDone:(BOOL)wait;

线程间通信示例 – 图片下载

代码1：

 1 //  2 // YYViewController.m
 3 // 06-NSThread04-线程间通信
 4 //  5 // Created by apple on 14-6-23.
 6 // Copyright (c) 2014年 itcase. All rights reserved.
 7 //
 8  9 #import "YYViewController.h" 10 @interface YYViewController ()
11 @property (weak, nonatomic) IBOutlet UIImageView *iconView;
12 @end 13 14 @implementation YYViewController
15 16 - (void)viewDidLoad
17 {
18  [super viewDidLoad];
19 }
20 21 -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 22 {
23 24 // 在子线程中调用download方法下载图片 25  [self performSelectorInBackground:@selector(download) withObject:nil];
26 }
27 28 29 30 -(void)download
31 {
32 //1.根据URL下载图片
33 //从网络中下载图片 34 NSURL *urlstr=[NSURL URLWithString:@"fdsf"];
35 36 //把图片转换为二进制的数据 37 NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时
38 39 //把数据转换成图片 40 UIImage *image=[UIImage imageWithData:data];
41 42 //2.回到主线程中设置图片 43  [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];
44 }
45 46 47 48 //设置显示图片 49 -(void)settingImage:(UIImage *)image
50 {
51 self.iconView.image=image;
52 }
53 54 @end

代码2：

 1 //  2 // YYViewController.m
 3 // 06-NSThread04-线程间通信
 4 //  5 // Created by apple on 14-6-23.
 6 // Copyright (c) 2014年 itcase. All rights reserved.
 7 //
 8  9 #import "YYViewController.h" 10 #import <NSData.h>
11 12 @interface YYViewController ()
13 @property (weak, nonatomic) IBOutlet UIImageView *iconView;
14 @end 15 16 @implementation YYViewController
17 18 - (void)viewDidLoad
19 {
20  [super viewDidLoad];
21 }
22 23 24 -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 25 {
26 // 在子线程中调用download方法下载图片 27 28  [self performSelectorInBackground:@selector(download) withObject:nil];
29 }
30 31 32 -(void)download
33 {
34 35 //1.根据URL下载图片
36 //从网络中下载图片 37 NSURL *urlstr=[NSURL URLWithString:@"fdsf"];
38 39 //把图片转换为二进制的数据 40 NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时
41 42 //把数据转换成图片 43 UIImage *image=[UIImage imageWithData:data];
44 45 //2.回到主线程中设置图片
46 //第一种方式
47 // [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];
48 49 //第二种方式
50 // [self.imageView performSelector:@selector(setImage:) onThread:[NSThread mainThread] withObject:image waitUntilDone:NO];
51 52 //第三种方式 53  [self.iconView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO];
54 }
55 56 57 //设置显示图片
58 //-(void)settingImage:(UIImage *)image
59 //{
60 // self.iconView.image=image;
61 //} 62 63 @end