如何在objective-c的actionSheet中自動選擇一個選項？

Question

- (IBAction)showActionSheet:(UIButton *)sender { 

     UIActionSheet *actionSheet = [[UIActionSheet alloc]initWithTitle:@"Select the operation to proceed?"delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:@"Delete" otherButtonTitles:@"Create", @"Update", @"Duplicate", nil] ; 
      [actionSheet showInView:self.view]; 

} 

如果沒有選擇任何內容，自動選擇取消;基於計時器，例如， 5秒後景氣取消？

UIActionSheet不UIAlertController因爲我想使的iOS 7.1兼容的二進制文件

Answer 1

[self.actionSheet dismissWithClickedButtonIndex:[self.actionSheet cancelButtonIndex] 
          animated:YES]; 

或者例如：

- (IBAction)showActionSheet:(UIButton *)sender { 

     UIActionSheet *actionSheet = [[UIActionSheet alloc]initWithTitle:@"Select the operation to proceed?"delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:@"Delete" otherButtonTitles:@"Create", @"Update", @"Duplicate", nil] ; 
      [actionSheet showInView:self.view]; 
     [self performSelector:@selector(dismissActionSheet:) withObject:actionSheet afterDelay:5.0]; 
} 

-(void)dismissActionSheet:(UIActionSheet *)actionSheet{ 
    if(actionSheet){ 
     [actionSheet dismissWithClickedButtonIndex:[actionSheet cancelButtonIndex] 
    } 
}