正文
子线程里调用performSelector需要注意什么
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以下代码执行顺序是什么 ?
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- ( void )action { NSLog(@"1"); dispatch_queue_t queue = dispatch_get_global_queue(0, 0); dispatch_async(queue, ^{ NSLog(@"3"); [ self performSelector: @selector (test) withObject: nil afterDelay:0.0f]; NSLog(@"4"); }); NSLog(@"2"); } - ( void )test { NSLog(@"5"); } |
结果
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2019-07-02 09:24:18.492671+0800 ModelTest[12945:510979] 1 2019-07-02 09:24:18.492776+0800 ModelTest[12945:510979] 2 2019-07-02 09:24:18.492807+0800 ModelTest[12945:511386] 3 2019-07-02 09:24:18.493009+0800 ModelTest[12945:511386] 4 |
test方法没有调用。因为子线程里runloop默认是关闭的。改为一下代码后
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- ( void )action { NSLog(@"1"); dispatch_queue_t queue = dispatch_get_global_queue(0, 0); dispatch_async(queue, ^{ NSLog(@"3"); [ self performSelector: @selector (test) withObject: nil afterDelay:0.0f]; [[NSRunLoop currentRunLoop]run]; NSLog(@"4"); }); NSLog(@"2"); } - ( void )test { NSLog(@"5"); } |
结果
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2019-07-02 09:38:40.874213+0800 ModelTest[13094:524707] 1 2019-07-02 09:38:40.874530+0800 ModelTest[13094:524707] 2 2019-07-02 09:38:40.874551+0800 ModelTest[13094:524802] 3 2019-07-02 09:38:43.792863+0800 ModelTest[13094:524802] 5 2019-07-02 09:38:43.793109+0800 ModelTest[13094:524802] 4 |
