@Binding for child communication in iOS Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of @Binding in SwiftUI?

@Binding allows a child view to read and write a value owned by a parent view. It creates a two-way connection so changes in the child update the parent.

beginner

How do you declare a @Binding property in a child view?

Use @Binding var propertyName: Type inside the child view struct to declare a binding property.

beginner

How does a parent pass a binding to a child view?

The parent passes a binding by prefixing the state variable with a $ sign, like ChildView(propertyName: $parentState).

intermediate

What happens if a child view modifies a @Binding property?

Modifying a @Binding property updates the original source of truth in the parent view, causing the UI to refresh accordingly.

intermediate

Why is @Binding preferred over passing values directly for child communication?

@Binding keeps data in sync between parent and child without duplicating state, avoiding bugs and making UI reactive.

What symbol do you use to pass a binding from a parent to a child view?

A $

B &

C *

D #

In SwiftUI, the $ prefix is used to pass a binding to a child view.

Which property wrapper allows a child view to modify a parent's state?

A @State

B @ObservedObject

C @Binding

D @EnvironmentObject

@Binding creates a two-way connection so the child can modify the parent's state.

If a child view changes a @Binding property, what happens?

A Only the child view updates

B The parent view's state updates

C Nothing changes

D The app crashes

Changing a @Binding property updates the parent's source of truth and refreshes the UI.

Which of these is NOT true about @Binding?

A It duplicates the state in the child

B It requires a parent to own the state

C It keeps data in sync

D It allows two-way data flow

@Binding does NOT duplicate state; it references the parent's state directly.

Where do you declare the @Binding property in SwiftUI?

A In the parent view

B In the SceneDelegate

C In the AppDelegate

D In the child view

@Binding is declared in the child view to receive a reference to the parent's state.

Explain how @Binding enables communication between a parent and child view in SwiftUI.

Think about how changes in the child affect the parent.

Describe the steps to pass a state variable from a parent view to a child view using @Binding.

Focus on property wrappers and passing syntax.