Can you explain the working principle of AutoLayout in iOS interfaces?

AutoLayout is a layout system in iOS that allows you to describe the positioning and sizing rules of UI elements using constraints. Instead of setting fixed coordinates and sizes, you specify relationships between elements (for example, "the button should be 20 points below the header" or "the button's width should be half of the screen width").

AutoLayout automatically calculates the positions and sizes of elements based on these constraints, enabling the interface to adapt to different screen sizes, orientations, and localizations.

Example of a constraint in Swift code:

button.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
    button.topAnchor.constraint(equalTo: view.topAnchor, constant: 20),
    button.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
    button.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20),
    button.heightAnchor.constraint(equalToConstant: 50)
])

Here, the button will be positioned with 20-point margins from the top and sides, and will have a height of 50 points.