iOS多线程技术

- (void)viewDidLoad
{
    [super viewDidLoad];
    //1.串行队列(队列里面的操作串行执行)
    self.serialQueue = dispatch_queue_create("串行对列",DISPATCH_QUEUE_SERIAL);
    //2.并发队列(队列里面的操作并发执行)
    self.concurrentQueue = dispatch_queue_create("并行队列",DISPATCH_QUEUE_CONCURRENT);
    //3.全局队列(系统自带并发队列)
    self.globalQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    //4.主队列(与主线程相关)
    self.mainQueue = dispatch_get_main_queue();
    NSLog(@"主线程%@",[NSThread currentThread]);
    //[self gcdCommunicate];
}

/**
 * 同步函数dispatch_sync不会开启新线程
 */
- (void)sync
{
    //在串行队列中同步执行操作
    for(int i = 0;i<10;i++){
        dispatch_sync(self.serialQueue, ^{
            NSLog(@"同步串行%@--%d",[NSThread currentThread],i);
        });
    }
    //在并发队列中同步执行操作
    for(int i = 0;i<10;i++){
        dispatch_sync(self.concurrentQueue, ^{
            NSLog(@"同步并发%@",[NSThread currentThread]);
        });
    }
    //在全局队列中同步执行操作
    for(int i = 0;i<10;i++){
        dispatch_sync(self.globalQueue, ^{
            NSLog(@"同步全局%@",[NSThread currentThread]);
        });
    }
    //在主队列中同步执行操作
#warning 在主线程中执行同步操作会卡住
    dispatch_sync(self.mainQueue, ^{
        NSLog(@"同步主%@",[NSThread currentThread]);
    });
}
/**
 * 异步函数dispatch_async会开启新线程
 */
- (void)async
{
    //在串行队列中异步执行操作(开启一条子线程,操作串行执行)
    for(int i = 0;i<10;i++){
        dispatch_async(self.serialQueue, ^{
            NSLog(@"异步串行%@---%d",[NSThread currentThread],i);
        });
    }
    //在并发队列中异步执行操作(开启多条子线程,操作并发执行)
    for(int i = 0;i<10;i++){
        dispatch_async(self.concurrentQueue, ^{
            NSLog(@"异步并发%@---%d",[NSThread currentThread],i);
        });
    }
    //在全局队列中异步执行操作(开启多条子线程,操作并发执行)
    for(int i = 0;i<10;i++){
        dispatch_async(self.globalQueue, ^{
            NSLog(@"异步全局%@---%d",[NSThread currentThread],i);
        });
    }
    //在主队列中异步执行操作(在主线程上执行,操作串行执行)
    for(int i = 0;i<10;i++){
        dispatch_async(self.globalQueue, ^{
            NSLog(@"异步主%@---%d",[NSThread currentThread],i);
        });
    }
}

/**
 * GCD的线程通信
 */
- (void)gcdCommunicate
{
    dispatch_async(self.globalQueue, ^{
        NSLog(@"当前线程%@", [NSThread currentThread]);
        // 下载图片
        NSURL *url = [NSURL URLWithString:@"http://news.baidu.com/z/resource/r/image/2014-06-22/2a1009253cf9fc7c97893a4f0fe3a7b1.jpg"];
        NSData *data = [NSData dataWithContentsOfURL:url]; 
        UIImage *image = [UIImage imageWithData:data];
        
        // 回到主线程显示图片
        dispatch_async(self.mainQueue, ^{
            NSLog(@"当前线程%@", [NSThread currentThread]);
            self.imageView.image = image;
        });
    });
}

/**
 * NSInvocationOperation的使用
 */
- (void)invocationOperation
{
    // 1.创建操作对象, 封装要执行的操作
    NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(callback) object:nil];
    // 2.启动操作(默认情况下,如果操作没有放到队列queue中,都是同步执行)
    [operation start];
}
- (void)callback
{
    NSLog(@"当前线程%@",[NSThread currentThread]);
}
/**
 * NSBlockOperation的使用
 */
- (void)blockOperation
{
    // 1.创建操作对象, 封装要执行的操作
    NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"当前线程%@--操作1",[NSThread currentThread]);
    }];
    [operation addExecutionBlock:^{
        NSLog(@"当前线程%@--操作2",[NSThread currentThread]);
    }];
    [operation addExecutionBlock:^{
        NSLog(@"当前线程%@--操作3",[NSThread currentThread]);
    }];
    //监听操作
    operation.completionBlock = ^(){
        NSLog(@"当前线程%@--操作完毕", [NSThread currentThread]);
    };
    // 2.启动操作(如果只有一个操作不会开启线程,如果有多个操作,就会开启新线程)
    [operation start];
}
/**
 * NSOperationQueue的使用
 */
- (void)OperationQueue
{
    //1.创建操作队列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    //设置队列的最大并发数
    queue.maxConcurrentOperationCount = 3;
    //2.创建操作
    NSBlockOperation *operation1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"当前线程%@-操作1",[NSThread currentThread]);
    }];
    NSBlockOperation *operation2 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"当前线程%@-操作2",[NSThread currentThread]);
    }];
    NSInvocationOperation *operation3 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(invocation) object:nil];
    
    //设置依赖
    //[operation2 addDependency:operation1];
    //[operation3 addDependency:operation2];
    
    
    //3.操作放在队列中
    [queue addOperation:operation1];
    [queue addOperation:operation2];
    [queue addOperation:operation3];
}
- (void)invocation
{
    NSLog(@"当前线程%@-操作3",[NSThread currentThread]);
}