取消按钮和UIActionSheet的问题

Question

How do I determine if the cancel button was pressed on a UIActionSheet?

My UIActionSheet is set up like this:

-(IBAction)fileButtonPressed
{
    UIActionSheet *mymenu = [[UIActionSheet alloc] 
                             initWithTitle:@"Select Folder" 
                             delegate:self 
                             cancelButtonTitle:@"Cancel" 
                             destructiveButtonTitle:nil 
                             otherButtonTitles:nil];

    for (i=0; i<3; i++) 
    { 
        [mymenu addButtonWithTitle:@"Button Name"]; 
    }

    [mymenu showInView:self.view];

}

The problem that I have is that I cannot differentiate between the cancel button and the first button selected.

-(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{  
    NSString *option = [actionSheet buttonTitleAtIndex:buttonIndex];

    //buttonIndex == 0 if the cancel button is pressed or 
    //if the first item is pressed.
}

Is there a better way of setting this up?

Answer 1

The trick turns out to be not to use the automatic cancel button but to add it yourself.

The other slight gotcha is to add the cancel button at the end and not at the beginning.

-(IBAction)fileButtonPressed
{
    UIActionSheet *mymenu = [[UIActionSheet alloc] 
                             initWithTitle:@"Select Folder" 
                             delegate:self 
                             cancelButtonTitle:nil 
                             destructiveButtonTitle:nil 
                             otherButtonTitles:nil];
    for (int nb=0; nb<3; nb++) 
    { 
        [mymenu addButtonWithTitle:@"Button Name"]; 
    }

    mymenu.cancelButtonIndex = [mymenu addButtonWithTitle: @"Cancel"];

    [mymenu showInView:self.view];
}

credit to this stackoverflow entry for the answer.

Answer 2

if (buttonIndex == actionSheet.cancelButtonIndex)
{
    // Handle cancel action
}

UIActionSheet also has properties like destructiveButtonIndex and firstOtherButtonIndex to compare against.

Answer 3

add this

[mymenu showInView:self.parentViewController.tabBarController.view];