多线程常用方法总结

NSThread

开线程的三种方法

1. [[NSThread alloc]initWithTarget:self selector:@selector(run:) object:@"dd"]

2. [self performSelectorInBackground:@selector(run:) withObject:@"dd"]

3. [NSThread detachNewThreadSelector:@selector(run:) toTarget:self withObject:@"dd"]

GCD

创建队列

1. dispatch_queue_t queue = dispatch_get_main_queue();//获得主线程串行队列

2. dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);//获得全局并发队列

3. dispatch_queue_t queue = dispatch_queue_create("aaa", DISPATCH_QUEUE_CONCURRENT);//创建一个新队列，第一个参数为唯一标识符，第二个是指定队列是并发还是串行

添加任务

1. dispatch_async(queue, ^{
NSLog(@"----下载图片1----%@", [NSThread currentThread]);
});//添加异步任务

2. dispatch_sync(queue, ^{
NSLog(@"----下载图片2----%@", [NSThread currentThread]);
});//添加同步任务

NSOperation

三种添加任务的方法

1. NSBlockOperation *operation = [[NSBlockOperation alloc]init];
[operation addExecutionBlock:^{
NSLog(@"----下载图片1----%@", [NSThread currentThread]);
}];

2. NSBlockOperation *operation2 = [NSBlockOperation blockOperationWithBlock:^{
NSLog(@"----下载图片2----%@", [NSThread currentThread]);
}];

3. NSInvocationOperation *operation1 = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(run:) object:@"aaa"];

队列

1. NSOperationQueue *queue = [[NSOperationQueue alloc]init];//初始化队列
2. queue.maxConcurrentOperationCount = 2;//设置当前最大操作数
3. [operation addDependency:operation1];//设置操作依赖
4. [queue addOperation:operation];//队列添加操作