Simultaneous animation when entering editing mode of UITableViewCell

when entering the editing mode in a UITableViewCell through setEditing:animated:, there is an (implicit) animation where the cells move right and the delete "buttons" appear at the left.

How do I manage, probably with Core Animation features, to run a second animation simultaneously to the first animation when entering editing mode, i.e. with the the same starting time, duration, timing curve, and so on? (I'm actually trying to change the width of a cell's sublayer synchronously.)

I studied the Core Animation Programming Guide and tried some of the techniques in a custom UITableViewCell class, f开发者_如何学Cor example by overriding willTransitionToState:. In principle, everything works well, however, I can only manage to have the animations one after the other, but not simultaneously.

Any advice is greatly appreciated.

Alright, it's much simpler than I initially thought. The behavior I sought can rather easily be achieved by correctly initializing the layers (or views) in the custom UITableViewCell. However, I realized that the order and, e.g., whether you manipulate bounds or frame properties is quite important.

The following code snippet does the job for a cell in a grouped UITableView. In this example, a CAGradientLayer (as an example for a CALayer) is added as a sublayer to a UIView, which itself is added as a subview to self.contentView of the cell. The subview's frame is tweaked to fit into the contentView. The code goes, e.g., into initWithStyle:reuseIdentifier: of a custom UITableViewCell:

CGRect realFrame = self.contentView.frame;
realFrame.size.width += 20;
UIView *gradientView = [[UIView alloc] initWithFrame:realFrame];

CAGradientLayer *gradientLayer = [[CAGradientLayer alloc] init];
gradientLayer.anchorPoint = CGPointMake(0.0, 0.0);
gradientLayer.frame = gradientView.frame;
gradientLayer.position = CGPointMake(0.0, 0.0);
[gradientLayer setColors:[NSArray arrayWithObjects:(id)[[UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0] CGColor], (id)[[UIColor clearColor] CGColor], nil]];
gradientLayer.startPoint = CGPointMake(0.5, 0.0);
gradientLayer.endPoint = CGPointMake(0.5, 1.0);

gradientView.layer.masksToBounds = YES;
gradientView.layer.cornerRadius = 8.0;

[gradientView.layer insertSublayer:gradientLayer atIndex:0];
[self.contentView addSubview:gradientView];

gradientView.autoresizingMask = UIViewAutoresizingFlexibleWidth;

[gradientView release];
[gradientLayer release];