iOS多线程初见

1. 三种创建线程的方法

//第一种

     NSThread * thread1 = [[NSThread alloc] initWithTarget:self selector:@selector(doAction) object:nil];

    //线程名

    thread1.name = @"thread1";

    //线程优先级，0 ~ 1

    thread1.threadPriority = 1.0;

    //开启线程

    [thread1 start];

//第二种

    //通过类方法创建线程,不用显示的开启start

    [NSThread detachNewThreadSelector:@selector(doAction) toTarget:self withObject:nil];

//第三种

    //隐式创建多线程

    [self performSelectorInBackground:@selector(doAction:) withObject:nil];

    

 

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    

 

    NSLog(@"mainThread - %@",[NSThread mainThread]);

 

    NSThread * thread = [[NSThread alloc] initWithTarget:self selector:@selector(handleAction) object:nil];

    

    //就绪状态

    [thread start];

}

 

- (void)handleAction {

    

    for (NSInteger i = 0 ; i < 100; i ++) {

        

        //阻塞状态

//        [NSThread sleepForTimeInterval:2];

//        [NSThread sleepUntilDate:[NSDate dateWithTimeIntervalSinceNow:2]];

        

//        NSLog(@"%@,%@",[NSThread currentThread],@(i));

        //可以在子线程获取主线程

        NSLog(@"mainThread - %@",[NSThread mainThread]);    

        if (i == 10) {

            //退出

            [NSThread exit];

        } 

    }

}

3.同步代码块实现买票功能

@implementation ViewController

 

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    

    self.tickets = 20;

    

    NSThread * thread1 = [[NSThread alloc] initWithTarget:self selector:@selector(saleTicket) object:nil];

//    thread1.name = @"computer";

    

    [thread1 start];

 

    

    NSThread * thread2 = [[NSThread alloc] initWithTarget:self selector:@selector(saleTicket) object:nil];

//    thread2.name = @"phone";

    

    [thread2 start];

}

 

- (void)saleTicket {

    

    

    while (1) {

    

//        [NSThread sleepForTimeInterval:1];

        

        

        //token必须所有线程都能访问到,一般用self

        

//        @synchronized() {

        

            //代码段

//        }

        

        

//        NSObject * o = [[NSObject alloc] init];

        

        //互斥锁

        @synchronized(self) {

            

            [NSThread sleepForTimeInterval:2];

            

            if (self.tickets > 0) {

                

                NSLog(@"%@ 还有余票 %@ 张",[NSThread currentThread],@(self.tickets));

                

                self.tickets -- ;

                

            } else {

                

                NSLog(@"票卖完了");

                

                break;

            }

            

        }

  

    }

    

}