presentModalViewController in CGRect - iphone

Question

Is it possible to present a modal view controller in such a way that the modal view is confined to the space included in a CGRect?
If not, please explain how to replicate the cross-disolve modal view transition between two views.
Thanks.

Answer 1

To cross-dissolve to a regular view controller, you can set it's modalTransitionStyle to UIModalTransitionStyleCrossDissolve then present it modally.
To perform a cross-dissolve between some pair of subviews (confined to their frame CGRects), you can use this UIView method:
+ (void)transitionFromView:(UIView *)fromView toView:(UIView *)toView duration:(NSTimeInterval)duration options:(UIViewAnimationOptions)options completion:(void (^)(BOOL finished))completion.
Here's how you might use that in code:
#interface ViewController ()
#property(strong,nonatomic) UIView *redView;
#property(strong,nonatomic) UIView *blueView;
#end
#implementation ViewController
#synthesize redView=_redView;
#synthesize blueView=_blueView;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.redView = [[UIView alloc] initWithFrame:CGRectMake(40.0, 40.0, 240.0, 100.0)];
self.redView.backgroundColor = [UIColor redColor];
[self.view addSubview:self.redView];
self.blueView = [[UIView alloc] initWithFrame:CGRectMake(40.0, 40.0, 240.0, 100.0)];
self.blueView.backgroundColor = [UIColor blueColor];
}
- (IBAction)crossDisolve:(id)sender {
UIView *fromView = (self.redView.superview)? self.redView : self.blueView;
UIView *toView = (fromView==self.redView)? self.blueView : self.redView;
[UIView transitionFromView:fromView
toView:toView
duration:1.0
options:UIViewAnimationOptionTransitionCrossDissolve
completion:^(BOOL finished) {NSLog(#"done!");}
];
// now the fromView has been removed from the hierarchy and the toView has been added
// please note that this code depends on ARC to release objects correctly
}
The harder part of your question is the idea of making that new sub-view "modal" by which I'm guessing you mean that covers only part of the display but takes input focus exclusively. The nearest thing to that in the SDK is UIAlertView.

Answer 2

How about you just use UIView animations:
UIView* view = [[UIView alloc] initWithFrame:CGRectMake(x,y,w,h)];
[view setAlpha:0];
[self.view addSubView:view];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.5];
[view setAlpha:1];
[UIView commitAnimations];
Voila! It fades in! :)