在iPhone操作系统中,在执行任务时是否可以不使用多线程来更新视图?

最简单的方法是将任务分成小块,并在计时器上执行它们,以便runloop可以处理UI事件:

static NSMutableArray *tasks;

- (void)addTask:(id)task
{
    if (tasks == nil)
        tasks = [[NSMutableArray alloc] init];
    [tasks addObject:task];
    if ([tasks count] == 1)
        [self performSelector:@selector(executeTaskAndScheduleNextTask) withObject:nil afterDelay:0.0];
}

- (void)executeTaskAndScheduleNextTask
{
    id task = [tasks objectAtIndex:0];
    [tasks removeObjectAtIndex:0];
    // Do something with task
    NSLog(@"finished processing task: %@", task);
    // Sechedule processing the next task on the runloop
    if ([tasks count] != 0)
        [self performSelector:@selector(executeTaskAndScheduleNextTask) withObject:nil afterDelay:0.0];
}

^{不过,后台线程有助于获得更好的用户体验,而且实际上可能更简单,这取决于您正在执行的操作。}