iOS线程通信

1、线程通信的概念

     1)一个线程传递数据给另一个线程；

     2)在一个线程中执行完特定任务后，转到另一个线程继续执行任务；

2、实例

     图片下载显示：

     - (IBAction)add:(id)sender {

    [selfperformSelectorInBackground:@selector(downLoad)withObject:nil];

     }

     - (IBAction)delet:(id)sender {

    self.imageView.image=nil;

    }

    -(void)downLoad

   {

    NSString*urlStr=@"http://www.0739i.com.cn/data/attachment/portal/201603/09/120156l1yzzn747ji77ugx.jpg";

    NSData*data=[NSDatadataWithContentsOfURL:[NSURLURLWithString:urlStr]];

    UIImage*image=[UIImageimageWithData:data];

    

    [selfperformSelectorOnMainThread:@selector(downLoadDone:)withObject:image waitUntilDone:NO];

   }

   -(void)downLoadDone:(UIImage*)image

   {

     NSLog(@"currentThread2=%@",[NSThreadcurrentThread]);

    self.imageView.image=image;

   }