iOS7: We cannot modify UIAlertView directly now.

From iPhoneOS 1 to 6, each experienced iOS programmer knows how to modify UIAlertView for appearance customization. For example, to add some UI elements like UILabel or a secure UITextField for password input, etc. One of our little tool keyOne used this trick.

But this doesn’t work in recent iOS7 beta. The reason is simple after checking view hierarchy in debugger. This is keyWindow when a UIAlertView popped up:

(lldb) po [[UIApplication sharedApplication] keyWindow]
<_UIModalItemHostingWindow: 0xb2dba70; frame = (0 0; 320 568); gestureRecognizers = <NSArray: 0xb2d5f20>; layer = <UIWindowLayer: 0xb2dbb50>>

and a view for alert exactly

(lldb) po [[[[[UIApplication sharedApplication] keyWindow] subviews] objectAtIndex:1] subviews]
<__NSArrayM 0xc975e80>(
<UIView: 0xb2e83a0; frame = (0 0; 320 568); layer = <CALayer: 0xb2e8770>>,
<_UIModalItemRepresentationView: 0xb2e5de0; frame = (25 184; 270 200); layer = <CALayer: 0xb2e5da0>>
)

The UIAlertView returned to caller is a stub only

lldb) po alertView
<PasswordPrompt: 0xb2c7f80; baseClass = UIAlertView; frame = (0 0; 0 0); opaque = NO; layer = <CALayer: 0xb2a1cc0>>

The view has zero size so we certainly cannot customize it.