使用NSThread开辟线程有两种方式：
（1）手动开启方式的创建：
NSThread *thread = [[NSThread alloc]initWithTarget:self selector:@selector(thread) object:@"thread"];
[thread start];// 开启线程
（2）自动开启方式的创建：
[NSThread detachNewThreadSelector:@selector(thread1:) toTarget:self withObject:@"thread1"];
- (void)thread1:(NSString *)sender{
[NSThread currentThread];//获取到当前所在的信息
NSThread *thread = [NSThread currentThread];
// thread.name = @"我是子线程 ";
// NSLog(@"%@",thread);
//// [NSThread isMainThread] 判断当前线程是否是主线程
// BOOL isMainThread = [NSThread isMainThread];
//// [NSThread isMultiThreaded] 判断是否是多线程
// BOOL isMUltiThread = [NSThread isMultiThreaded];
// NSLog(@"%d，%d",isMainThread,isMUltiThread);
//// 设置线程的优先级(0-1) setThreadPriority:
// [NSThread setThreadPriority:1.0];
//// sleepForTimeInterval:让线程休眠
// [NSThread sleepForTimeInterval:2];
// 从网络加载图片并将它转化为data类型的数据
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:kUrl]];
image = [UIImage imageWithData:data];
// waiUntilDone设为YES，意味着UI更新完才会做其它操作
[self performSelectorOnMainThread:@selector(updateUI:) withObject:image waitUntilDone:YES];
}
