OC原理之多线程(二)

对于如下代码的，它的打印结果是什么

NSThread *thread = [[NSThread alloc] initWithBlock:^{
        NSLog(@"1");
    }];
    [thread start];
    [self performSelector:@selector(testhaha) onThread:thread withObject:nil waitUntilDone:true];

- (void)testhaha {
    NSLog(@"2");
}

运行之后打印结果如下:

2021-02-23 23:59:45.245881+0800 KVOTest[17729:646223] 1
2021-02-23 23:59:45.253879+0800 KVOTest[17729:646135] *** Terminating app due to uncaught exception 'NSDestinationInvalidException', reason: '*** -[ViewController performSelector:onThread:withObject:waitUntilDone:modes:]: target thread exited while waiting for the perform'
*** First throw call stack:

从报错来看，在执行testhaha方法的时候，线程已经退出

解决方法，开启runloop，延长线程的时间:

NSThread *thread = [[NSThread alloc] initWithBlock:^{
        NSLog(@"1");
        [[NSRunLoop currentRunLoop] addPort:[[NSPort alloc] init] forMode:NSRunLoopCommonModes];
        [[NSRunLoop currentRunLoop] run];
    }];
    [thread start];
    [self performSelector:@selector(testhaha) onThread:thread withObject:nil waitUntilDone:true];

- (void)testhaha {
    NSLog(@"2");
}