消鍵盤的三種方式

//一次把view上面的所有text field的鍵盤都消完

[self.view endEditing:YES];

//針對某個text field去消鍵盤

[self.textBox resignFirstResponder];

//如果要用鍵盤上return key的方式，要去實作textFiled的did end on exit的方法
再在方法中加入以上消鍵盤的方法即可
//或者在離開textField的時候實作

- (IBAction)TextField_DidEndOnExit:(id)sender {
    [sender resignFirstResponder];
}

P.S.消鍵盤的設定，都要在main thread完成，不然會導致app crash.

*** Assertion failure in -[UIKeyboardTaskQueue waitUntilAllTasksAreFinished], /SourceCache/UIKit/UIKit-2935.138/Keyboard/UIKeyboardTaskQueue.m:368

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[UIKeyboardTaskQueue waitUntilAllTasksAreFinished] may only be called from the main thread.'