MonoTouch - reuse UIAlertVIew?

Question

Should instances of UIAlertView be reused when possible?

Or is wrapping them in a using-block the best practice?

• For one situation, I created a (non-modal) MessageBox class (just like WinForms or WPF). I mainly use it for convenience.
• Another situation is a custom UIAlertView that I've subclassed that has more advanced layout. I wire-up the Dismissed event to do some work on close.

Would either of these situation call for a different approach?

Answer 1

I dont think there's any problem doing this in a using block - you may want to abstract out the handler so that you dont have alert box delegates all over the place that do the same thing.

then again the LoadingHUDView is a good example of needing to code out the functionality for more advanced things...

but either way - if you're reusing the same object but really changing it each time - there;s not much to be gained IMO

Answer 2

Here is how you could make your UIAlertView modal:

To do this, what you can do is to run the mainloop manually. I have not managed to stop the mainloop directly, so I instead run the mainloop for 0.5 seconds and wait until the user responds.

The following function shows how you could implement a modal query with the above approach:

int WaitForClick ()
{
    int clicked = -1;
    var x = new UIAlertView ("Title", "Message",  null, "Cancel", "OK", "Perhaps");
    x.Show ();
    bool done = false;
    x.Clicked += (sender, buttonArgs) => {
        Console.WriteLine ("User clicked on {0}", buttonArgs.ButtonIndex);
    clicked = buttonArgs.ButtonIndex;
    };    
    while (clicked == -1){
        NSRunLoop.Current.RunUntil (NSDate.FromTimeIntervalSinceNow (0.5));
        Console.WriteLine ("Waiting for another 0.5 seconds");
    }

    Console.WriteLine ("The user clicked {0}", clicked);
    return clicked;
}