1、创建线程

第一种创建方式： alloc init特点：(1) 需要手动开启线程;(2) 可以拿到线程对象，进行详细设置； NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(showmsg) object:nil]; [thread start];iOS10方法 NSThread *thread = [NSThread alloc] initWithBlock:<#^(void)block#>  [thread start];  第二种创建方式：detachNewThreadSelector特点：自动启动线程，无法对线程进行更详细的设置[NSThread detachNewThreadSelector:@selector(showmsg) toTarget:self withObject:nil];第三种创建方式：performSelector方法[self performSelector:@selector(showmsg) withObject:nil];[self performSelectorOnMainThread:@selector(showmsg) withObject:nil waitUntilDone:YES];

2、设置线程属性

//设置线程的名称thread.name = @"111"//设置线程的优先级,注意线程优先级的取值范围为0.0~1.0之间，1.0表示线程的优先级最高,如果不设置该值，那么理想状态下默认为0.5thread.threadPriority = 1.0;

3、线程的状态

//线程的各种状态：新建-就绪-运行-阻塞-死亡//常用的控制线程状态的方法[NSThread exit];//退出当前线程[NSThread sleepForTimeInterval:2.0];//阻塞线程[NSThread sleepUntilDate:[NSDate dateWithTimeIntervalSinceNow:2.0]];//阻塞线程[NSThread isMainThread]//判断是否是主线程[_thread start];//开启线程_thread.isCancelled;//线程的状态是否是取消状态，[_thread cancel];//设置线程的状态为取消状态，cancel只能设置线程的状态，不会停止线程，退出线程需要调用，[NSThread exit]//注意：线程死了不能复生

4、线程间通讯

- (void)viewDidLoad {    [super viewDidLoad];        //开启线程下载图片    NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(downLoadImage) object:nil];        [thread start];    }-(void)downLoadImage{    NSURL *url = [NSURL URLWithString:@"https://ss0.bdstatic.com/5aV1bjqh_Q23odCf/static/superman/img/logo/logo_white_fe6da1ec.png"];    NSData *data = [NSData dataWithContentsOfURL:url];    UIImage *image = [UIImage imageWithData:data];        //回到主线程刷新界面    [_imageView performSelector:@selector(setImage:) onThread:[NSThread mainThread] withObject:image waitUntilDone:YES];}