iOS开发多线程篇—线程间的通信

来源：互联网发布：网络协议概念三要素编辑：程序博客网时间：2024/05/16 11:48

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：

#import "CKViewController.h"  @interface CKViewController ()  @property (weak, nonatomic) IBOutlet UIImageView *iconView;  @end  @implementation CKViewController  - (void)viewDidLoad  {      [super viewDidLoad];  }  -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event  {  // 在子线程中调用download方法下载图片      [self performSelectorInBackground:@selector(download) withObject:nil];  }  -(void)download  {      //1.根据URL下载图片      //从网络中下载图片      NSURL *urlstr=[NSURL URLWithString:@"fdsf"];      //把图片转换为二进制的数据      NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时      //把数据转换成图片      UIImage *image=[UIImage imageWithData:data];      //2.回到主线程中设置图片      [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];  }  //设置显示图片  -(void)settingImage:(UIImage *)image  {      self.iconView.image=image;  }  @end

代码2：

#import "CKViewController.h"  #import <NSData.h>  @interface CKViewController ()  @property (weak, nonatomic) IBOutlet UIImageView *iconView;  @end  @implementation CKViewController  - (void)viewDidLoad  {      [super viewDidLoad];  }  -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event  {  // 在子线程中调用download方法下载图片      [self performSelectorInBackground:@selector(download) withObject:nil];  }  -(void)download  {      //1.根据URL下载图片      //从网络中下载图片      NSURL *urlstr=[NSURL URLWithString:@"fdsf"];      //把图片转换为二进制的数据      NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时      //把数据转换成图片      UIImage *image=[UIImage imageWithData:data];      //2.回到主线程中设置图片      //第一种方式  //    [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];      //第二种方式      //    [self.imageView performSelector:@selector(setImage:) onThread:[NSThread mainThread] withObject:image waitUntilDone:NO];      //第三种方式     [self.iconView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO];  }  //设置显示图片  //-(void)settingImage:(UIImage *)image  //{  //    self.iconView.image=image;  //}  @end

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