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 @end13 14 @implementation YYViewController15 16 - (void)viewDidLoad17 {18 [super viewDidLoad];19 }20 21 -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event22 {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)download31 {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 *)image50 {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 #import11 12 @interface YYViewController ()13 @property (weak, nonatomic) IBOutlet UIImageView *iconView;14 @end15 16 @implementation YYViewController17 18 - (void)viewDidLoad19 {20 [super viewDidLoad];21 }22 23 24 -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event25 {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)download33 {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 *)image59 //{60 // self.iconView.image=image;61 //}62 63 @end