呼籲

Question

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

和

[self customFoo:obj]; 

據我所知，如果第二個是在主線程調用，沒有他們兩個有什麼區別...是對？

他們兩人之間的基本區別是什麼？

Answer 1

運行時行爲是相同的。但是編譯代碼時會有差異：如果定義了方法customFoo:，則第二個代碼只會編譯。

Answer 2

performSelector：向接收方發送指定的消息並返回消息的結果。

PerformSelector用於調用方法，只要你想執行，這意味着你有選項來選擇不同的選項來執行特定的任務（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: //在後臺執行任務。所以，你ManinThread（應用程序）將不會停止responding..like多線程..

凡直接法（[self customFoo:obj];）將不會執行任務提供選擇..

For more and detailed explanation visit this reference..

希望，這將有助於你...