呼吁

Question

[self performSelectorOnMainThread:@selector(customFoo:) withObject:obj waitUntilDone:YES]; 

和

[self customFoo:obj]; 

据我所知，如果第二个是在主线程调用，没有他们两个有什么区别...是对？

他们两人之间的基本区别是什么？

Answer 1

运行时行为是相同的。但是编译代码时会有差异：如果定义了方法customFoo:，则第二个代码只会编译。

Answer 2

performSelector：向接收方发送指定的消息并返回消息的结果。

PerformSelector用于调用方法，只要你想执行，这意味着你有选项来选择不同的选项来执行特定的任务（方法）示例...

– performSelector:withObject:afterDelay: // will execute method after specific delay.. 
– performSelector:withObject:afterDelay:inModes: 
– performSelectorOnMainThread:withObject:waitUntilDone: 
– performSelectorOnMainThread:withObject:waitUntilDone:modes: 
– performSelector:onThread:withObject:waitUntilDone: 
– performSelector:onThread:withObject:waitUntilDone:modes: 

– performSelectorInBackground:withObject: //在后台执行任务。所以，你ManinThread（应用程序）将不会停止responding..like多线程..

凡直接法（[self customFoo:obj];）将不会执行任务提供选择..

For more and detailed explanation visit this reference..

希望，这将有助于你...