Should I call super layoutSubviews?

You always have to call [super layoutSubviews] last, if the intrinsic content size of a view will be changed. If you change the title of the button, the intrinsic content size of the UIButton will be changed, therefore the last call.

When should I call layoutSubviews?

Note specifically that is why layoutSubviews: is called whenever a UIScrollView scrolls, as it performs the scrolling by changing its bounds’ origin. Changing the frame will only change the bounds if the size has changed, as this is the only thing propagated to the bounds property.

Does setNeedsLayout call layoutSubviews?

setNeedsLayout() This will indicate to the system that the view’s layout needs to be recalculated. Instead, the views will update on the next update cycle, when the system calls layoutSubviews on those views and triggers subsequent layoutSubviews calls on all their subviews.

How many times is layoutSubviews called?

layoutSubviews is called when the view is created, but never again. My subviews are correctly laid out. If I toggle the in-call status bar off, the subview’s layoutSubviews is not called at all, even though the main view does animate its resize.

What is layoutSubviews?

layoutSubviews is the most common method to be overridden from the whole Auto Layout life cycle. You will do this when: Constraints are not enough to express view’s layout. Frames are calculated programmatically.

How do I use Uistackview?

The exact layout varies depending on the stack view’s axis , distribution , alignment , spacing , and other properties. To use a stack view, open the Storyboard you wish to edit. Drag either a Horizontal Stack View or a Vertical Stack View out from the Object library, and position the stack view where desired.

What is Invalidateintrinsiccontentsize?

Call this when something changes in your custom view that invalidates its intrinsic content size. This allows the constraint-based layout system to take the new intrinsic content size into account in its next layout pass.

What is the difference between setNeedsLayout and layoutIfNeeded?

The reason being layoutIfNeeded() forces the view to update immediately, while setNeedsLayout() only updates the view when the animation cycle comes. Thus, it is believed that layoutIfNeeded() is less system friendly as compared to setNeedsLayout().

What is UIStackView?

A streamlined interface for laying out a collection of views in either a column or a row.

What is Intrinsiccontentsize?

Intrinsic content size is information that a view has about how big it should be based on what it displays. For example, a label’s intrinsic content size is based on how much text it is displaying. In your case, the image view’s intrinsic content size is the size of the image that you selected.

What is setNeedsLayout?

setNeedsLayout() Invalidates the current layout of the receiver and triggers a layout update during the next update cycle.

What causes layoutsubviews to be called on addsubview?

Some of the points in BadPirate’s answer are only partially true: addSubview causes layoutSubviews to be called on the view being added, the view it’s being added to (target view), and all the subviews of the target. It depends on the view’s (target view) autoresize mask.

When to call layoutsubview on a UIView?

Example: if you created UIView programmatically (it has no autoresize mask by default), LayoutSubview will be called only when UIView frame changes not on every addSubview. It is through this technique that the performance of the application also increases.

When is layoutsubviews called in the UIScrollView?

Note specifically that is why layoutSubviews: is called whenever a UIScrollView scrolls, as it performs the scrolling by changing its bounds’ origin. Changing the frame will only change the bounds if the size has changed, as this is the only thing propagated to the bounds property.

What happens when the bounds of a subview change?

Its own bounds (not frame) changed. The bounds of one of its direct subviews changed. A subview is added to the view or removed from the view. The bounds are considered changed only if the new value is different, including a different origin.