NSThread

三种创建方式

NSThread的对象方法

- (void)threadDemo1 {

    NSLog(@"before %@", [NSThread currentThread]);

    NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(longOperation:) object:@"THREAD"];

    [thread start];

    NSLog(@"after %@", [NSThread currentThread]);

}
小结:在start方法执行完毕后,会在另一个线程执longOperation:方法

 NSThread的类方法

- (void)threadDemo2 {

    NSLog(@"before %@", [NSThread currentThread]);

    [NSThread detachNewThreadSelector:@selector(longOperation:) toTarget:self withObject:@"DETACH"];

    NSLog(@"after %@", [NSThread currentThread]);

}
小结:detachNewThreadSelector:类方法不需要启动;会自动创建线程并执行@selector方法

NSThread的类方法

- (void)threadDemo3 {

    NSLog(@"before %@", [NSThread currentThread]);

    [self performSelectorInBackground:@selector(longOperation:) withObject:@"PERFORM"];

    NSLog(@"after %@", [NSThread currentThread]);

}
小结:这是NSObject的分类方法,会在后台自动执行@selector方法;