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