NSOperationQueue waitUntillAllOperationsAreFinished阻止操作

Question

我已经创建了自己的NSOperation子类，现在我想让它的一些实例并行运行。由于这是一个并发的操作，我已经覆盖了

- (void)start {
    [self willChangeValueForKey:@"isExecuting"];
    isExecuting = YES;
    [self didChangeValueForKey:@"isExecuting"];

    error=NO;
    startedSection=NO;

    // start the task
    [task launch];
}

- (BOOL)isConcurrent {
    return YES;
}

- (BOOL)isExecuting {
    return isExecuting;
}

- (BOOL)isFinished {
    return isFinished;
}

并在操作完成时执行以下代码：

[self willChangeValueForKey:@"isExecuting"];
[self willChangeValueForKey:@"isFinished"];
isExecuting = NO;
isFinished = YES;
[self didChangeValueForKey:@"isExecuting"];
[self didChangeValueForKey:@"isFinished"];

当我将操作添加到[myQueue waitUntillAllOperationsAreFinished]之后添加myQueue时，所有操作都没有启动！当我删除[myQueue waitUntillAllOperationsAreFinished]时，我得到了我想要的东西，除了这可能导致一些错误，因为主线程干扰了这些操作......

Answer 1

如何实现操作的并发性？我怀疑你是在向主线程发送内容，而你也在-waitUntillAllOperationsAreFinished的主线程中阻塞了。那当然会陷入僵局。