iOS Minimize view and all subviews to top left - ios

Question

I have a UIView with a few subviews (and a few subviews in those). I am trying to minimize this entire view into the top left of the screen until it reaches a certain size (20 x 20) but am having trouble doing just that.
I first tried [UIView beginAnimations:nil context:nil]; but this didn't resize the subviews. Also, due to the padding and amount of other subviews, it would be very hard to set each subview frame to some new size and make it all work well.
I then tried this code:
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2.0f];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[self.myCardsCarousel.layer setAnchorPoint:CGPointMake(0.0f, 0.0f)];
[self.myCardsCarousel setTransform:CGAffineTransformMakeScale(0.0f, 0.0f)];
CGRect addCardsButtonFrame = self.addCardsButton.frame;
addCardsButtonFrame.size.height = 0.0f;
[self.addCardsButton setFrame:addCardsButtonFrame];
[UIView commitAnimations];
But this doesn't minimize to the top left of the screen. Instead, it minimizes to the dead center of the screen.
How can I anchor this to the top left of the screen? Also, how can I stop a CGAffineTransformMakeScale() when the view reaches a certain size?

Answer 1

One possible solution is to create a snapshot of the view, and animate the snapshot into the corner (assuming that it's ok for the minimized view to be static). The general sequence of events is
create a snapshot of the parent view into a memory bitmap
create a UIImageView from the snapshot
position the UIImageView in front of the parent view
hide the parent view using its hidden property
animate the UIImageView into the corner
To restore the view
animate the UIImageView back to its original location
unhide the parent view
remove the UIImageView and discard it
To start, you need a property for the UIImageView
#property (strong, nonatomic) UIImageView *snapshotView;
Here's the code to minimize the view
// create a snapshot image of the parent view
UIGraphicsBeginImageContextWithOptions( self.parentView.bounds.size, YES, 0 );
CGContextRef context = UIGraphicsGetCurrentContext();
[self.parentView.layer renderInContext:context];
UIImage *snapshot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// create a UIImageView from the snapshot
self.snapshotView = [[UIImageView alloc] initWithFrame:self.parentView.frame];
self.snapshotView.image = snapshot;
[self.view addSubview:self.snapshotView];
// hide the parent view in place, while animating the snapshot view into the corner
self.parentView.hidden = YES;
[UIView animateWithDuration:0.5 delay:0 options:UIViewAnimationOptionCurveEaseInOut
animations:^
{
self.snapshotView.frame = CGRectMake( 0, 0, 20, 20 );
}
completion:nil];
Here's the code to restore the view
[UIView animateWithDuration:0.5 delay:0 options:UIViewAnimationOptionCurveEaseInOut
animations:^
{
// animate the snapshot view back to original size
self.snapshotView.frame = self.parentView.frame;
}
completion:^(BOOL finished)
{
// reveal the parent view and discard the snapshot view
self.parentView.hidden = NO;
[self.snapshotView removeFromSuperview];
self.snapshotView = nil;
}];