线程

子线程

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        [self postFile];

    });

   主线程

   dispatch_async(dispatch_get_main_queue(), ^{

                            [self mainQueue];

       });

  //self.thread=[[NSThread alloc]initWithTarget:self selector:@selector(postFile) object:nil];

    //[self.thread start];

[self performSelectorOnMainThread:@selector(mainQueue) withObject:nil waitUntilDone:YES];