NSOperationQueue mainQueue vs performSelectorOnMainThread？

Question

这有什么区别:

[[NSOperationQueue mainQueue] addOperationWithBlock:^{
    [self doSomthing:object];
}];

还有这个:

[self performSelectorOnMainThread:@selector(doSomething:) withObject:object waitUntilDone:NO]

Answer 1

[self performSelectorOnMainThread:@selector(doSomething:) 
                       withObject:object 
                    waitUntilDone:NO]

将在调用时正确执行选择器.如果要从后台线程影响UI,则必须使用此选项.如果说YES以waitUntilDone它会阻塞线程,直到方法完成.

mainQueue将该块添加到主线程的操作队列中,但不保证何时执行它.该队列中可能还有其他项目仍在等待执行.