NSInvocationOperation

适用场景

如果你正在对现有的application进行修改，并且application已经有了执行task的object和methods，不妨使用NSInvocationOperation。

For example: you could use an invocation operation to perform a selector that is chosen dynamically based on user input.

代码

- (NSOperation *)taskWithData:(id)data {

    NSInvocationOperation *invocationOpt = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(myTaskMethod:) object:data];
    return invocationOpt;
}

- (void)myTaskMethod:(id)data {

    NSLog(@"currentThread:%@ \n mainThread:%@ \n %@", [NSThread currentThread], [NSThread mainThread], data);
}

放入queue

MyTask *task = [[MyTask alloc] init];
NSOperationQueue *optQueue = [[NSOperationQueue alloc] init];
NSOperation *opt = [task taskWithData:@"event2"];
[optQueue addOperation:opt];

execute manually

MyTask *task = [[MyTask alloc] init];
NSOperation *opt = [task taskWithData:@"event2"];
if (opt.isReady && ![opt isCancelled]) {

    if (![opt isConcurrent]) {
        [opt start];
    } else {
        [NSThread detachNewThreadWithBlock:^{
            NSLog(@"event3");
        }];
    }
} else if ([opt isCancelled]) {

    [task willChangeValueForKey:@"isFinished"];
    [task willChangeValueForKey:@"isExecuting"];
    task.finished = YES;
    task.executing = NO;
    [task didChangeValueForKey:@"isExecuting"];
    [task didChangeValueForKey:@"isFinished"];
    }

放入queue和start manually区别

把operation放入queue，queue会为operation开辟一个thread，相当于concurrent。
而start manually，operation执行是和调用start的线程一样。即non-concurrent。

2017-01-23 14:20:56.805 ConcurrentTest[93064:1982269] event1
2017-01-23 14:20:56.805 ConcurrentTest[93064:1982313] currentThread:<NSThread: 0x7dd38130>{number = 3, name = (null)}
mainThread:<NSThread: 0x7be33250>{number = 1, name = (null)}
 event2
2017-01-23 14:20:56.806 ConcurrentTest[93064:1982269] event3

2017-01-23 14:19:56.238 ConcurrentTest[93032:1981303] event1
2017-01-23 14:19:56.238 ConcurrentTest[93032:1981303] currentThread:<NSThread: 0x79039370>{number = 1, name = main}
mainThread:<NSThread: 0x79039370>{number = 1, name = main}
 event2
2017-01-23 14:19:56.239 ConcurrentTest[93032:1981303] event3

NSInvocationOperation简单使用