Difference between layoutIfNeeded vs setNeedsLayout

In the context of user interface design and layout in iOS, layoutIfNeeded and setNeedsLayout are two methods that can be used to update the layout of a view and its subviews.

layoutIfNeeded

layoutIfNeeded is a method that forces the view to immediately update its layout and the layout of its subviews. This can be useful in situations where you need to ensure that the view is properly laid out before performing some other action, such as animating a change in the view's layout. However, using layoutIfNeeded can be expensive in terms of performance, since it causes the view to update its layout immediately, rather than waiting for the next update cycle.

setNeedsLayout

setNeedsLayout is a method that marks the view as needing to update its layout, but doesn't force the update to happen immediately. Instead, the view's layout will be updated during the next update cycle, which typically happens just before the view is displayed on the screen. This can be a more efficient approach than using layoutIfNeeded, since it allows the view to update its layout at a more optimal time, rather than immediately. However, it can also mean that the view's layout may not be updated immediately, which may not be suitable in some situations.

Overall, the choice of which method to use will depend on the specific needs and requirements of your application. In general, layoutIfNeeded is best used for cases where you need to ensure that a view's layout is updated immediately, while setNeedsLayout is best used for cases where you can afford to wait for the next update cycle to update the view's layout.

Originally published at https://needone.app on December 12, 2022.