基于RunLoop 实现 线程保活

只要线程中有一个启动重的runloop,则线程可以持续保活;
一个能持续运行的runloop想要有至少一个mode;
一个mode中至少有一个input source 或者一个 timer source;

实现代码:

-(void)viewDidLoad{
    [super viewDidLoad];
    [self task1];
}


-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self performSelector:@selector(task2) onThread:self.activeT withObject:nil waitUntilDone:YES];
}

-(void)task1{
    self.activeT = [[NSThread alloc] initWithBlock:^{
        NSLog(@"start%@",[NSThread currentThread]);
        [[NSRunLoop currentRunLoop] addPort:[NSPort port] forMode:NSRunLoopCommonModes];
        [[NSRunLoop currentRunLoop] run];
        NSLog(@"end");
    }];
    [self.activeT start];
}

-(void)task2{
    NSLog(@"task2%@",[NSThread currentThread]);
}