iOS开发多线程篇—线程间的通信

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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 #import <NSData.h>11 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

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