Question

I am trying to mimic UINavigationController’s pushViewController using UIView animation but I have seem to run into an issue. I cannot animate the self.view.frame.

This is the code I am using but self.view just won’t move!

    [self.view addSubview:myViewController.view];
    [myViewController.view setFrame:CGRectMake(320, 0, 320, 480)];    
    [UIView animateWithDuration:0.5 
                     animations:^{
                         [self.view setFrame:CGRectMake(-320, 0, 320, 480)];
                         [myViewController.view setFrame:CGRectMake(0, 0, 320, 480)];
                     }
                     completion:^(BOOL finished){
                         [view1.view removeFromSuperview];
                     }];

Thanks!

Answer 1

Consider where the views are just before the animations start:

• self.view.frame is (I assume) 0,0,320,380
• myViewController.view is a subview of self.view
• myViewController.view.frame is 320,0,320,480 in self.view‘s coordinate system, so it’s outside of its superview’s frame (and off the right edge of the screen)

Now consider where the views are after the animations finish:

• self.view.frame is -320,0,320,480
• myViewController.view is still a subview of self.view
• myViewController.view.frame is 0,0,320,480 in self.view‘s coordinate system, so it’s fully inside its superview’s frame, but its frame in screen coordinates is -320,0,320,480, so it is now entirely off the left edge of the screen

You need to make myViewController.view a sibling of self.view, not a subview. Try this:

// Calculate the initial frame of myViewController.view to be
// the same size as self.view, but off the right edge of self.view.
// I don't like hardcoding coordinates...
CGRect frame = self.view.frame;
frame.origin.x = CGRectGetMaxX(frame);
myViewController.view.frame = frame;
[self.view.superview addSubview:myViewController.view];
// Now slide the views over.
[UIView animationWithDuration:0.5 animations:^{
    CGRect frame = self.view.frame;
    myViewController.view.frame = frame;
    frame.origin.x -= frame.size.width;
    self.view.frame = frame;
} completion:^(BOOL done){
    [view1.view removeFromSuperview];
}];