2.1 NSThread 有两种直接创建方式：
- (id)initWithTarget:(id)target selector:(SEL)selector object:(id)argument
+ (void)detachNewThreadSelector:(SEL)aSelector toTarget:(id)aTarget withObject:(id)anArgument
第一个是实例方法，第二个是类方法
- 1、[NSThread detachNewThreadSelector:@selector(doSomething:) toTarget:self withObject:nil];
- 2、NSThread* myThread = [[NSThread alloc] initWithTarget:self
- selector:@selector(doSomething:)
- object:nil];
- [myThread start];
NSThread的使用
原文：http://www.cnblogs.com/BinZone/p/4462862.html
