создать текстовое поле как подпредставление UIAlertView
// Ask for Username and password.
alertView = [[UIAlertView alloc] initWithTitle:_title message:@"\n \n \n" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK", nil];
// Adds a username Field
utextfield = [[UITextField alloc] initWithFrame:CGRectMake(12.0, 45.0, 260.0, 25.0)];
utextfield.placeholder = @"Username";
[utextfield setBackgroundColor:[UIColor whiteColor]];
utextfield.enablesReturnKeyAutomatically = YES;
[utextfield setReturnKeyType:UIReturnKeyDone];
[utextfield setDelegate:self];
[alertView addSubview:utextfield];
// Show alert on screen.
[alertView show];
[alertView release];