IOS 学习NSOperation

定义一个全局的队列

@property (nonatomic,strong)NSOperationQueue *opQueue;

初始化对象

-(NSOperationQueue *)opQueue{

if (_opQueue ==nil) {

    _opQueue = [[NSOperationQueuealloc]init];
}
return_opQueue;
}

设置最大并发数:不是线程的数量，而是同时执行操作的数量

self.opQueue.maxConcurrentOperationCount = 2;
for (int i =0; i < 20 ; i++) {
    NSOperation *bp = [NSBlockOperationblockOperationWithBlock:^{
        [NSThreadsleepForTimeInterval:1];
        NSLog(@"%@ %d",[NSThreadcurrentThread],i);
    }];
    [self.opQueue addOperation:bp];
}

挂起：暂停和继续

self.opQueue.suspended

取消队列里的所有操作，取消操作并不会影响队列的挂起状态

[self.opQueue cancelAllOperations];
  //取消队列里的挂起状态
self.opQueue.suspended =NO;

一：相当于GCD的并发(全局)队列

//主队列:与GCD主队列一致

NSOperationQueue *opq =[NSOperationQueuemainQueue];

//创建多个操作:相当于GCD的异步执行的任务

for (int i =0; i < 20 ; i++) {

    NSOperation *op = [NSBlockOperationblockOperationWithBlock:^{
        NSLog(@"%@ %d",[NSThreadcurrentThread],i);
    }];
    [opq addOperation:op];
}

二：依赖队列

  NSOperationQueue *opq = [[NSOperationQueuealloc]init];
//常用写法

for (int i =0; i < 20 ; i++) {

    [opq addOperationWithBlock:^{

        NSLog(@"%@ %d",[NSThreadcurrentThread],i);

    }];

}
//NSBlockOperation

NSBlockOperation *op1 = [NSBlockOperationblockOperationWithBlock:^{

    NSLog(@"op1 %@",[NSThreadcurrentThread]);}];

[op1 addExecutionBlock:^{

    NSLog(@"op1-11111");

}];

//NSInvocationOperation 不常用

NSOperation *op2 = [[NSInvocationOperationalloc]initWithTarget:selfselector:@selector(task:)object:@"Invocation"]; //多态的写法

//依赖关系，可以跨队列，注意不要出现循环依赖

[op2 addDependency:op1];

//设置等待

[opq addOperations:@[op1,op2]waitUntilFinished:YES];

NSLog(@"等待执行");

//线程间通信:在主线程里更新UI

NSBlockOperation *op3 = [NSBlockOperationblockOperationWithBlock:^{

    NSLog(@"更新UI......%@",[NSThreadcurrentThread]);}];

[[NSOperationQueuemainQueue] addOperation:op3];

[op3 addDependency:op2]; //依赖关系，可以跨队列