FragmentContainerView

FragmentContainerView is a fragment-specific container based on FrameLayout. A fragment transaction can address this view by its ID.

Pass an explicit ID when transaction code needs a known container ID. If id is omitted, the inherited View initializer generates one.

The component provides an initializer without a body closure and a builder-closure overload. Fragment manager and transaction APIs belong to FragmentActivity, FragmentManager, and FragmentTransaction.

Use it when…

Use it when a layout needs a dedicated fragment host that a transaction can target by ID. An explicit ID lets the layout and the transaction refer to the same slot.

How it behaves

FragmentContainerView extends FrameLayout, so its inherited width and height modifiers can request .matchParent sizing for a child of a FrameLayout. These modifiers express a sizing request; they do not establish final geometry or window attachment.

FragmentActivity provides access to a fragment manager. The manager creates transactions and reports whether its state has been saved; a transaction can request replacement for a container ID. These APIs are separate from the container view.

Examples

Add a fragment slot to a host

This builds a FrameLayout with a FragmentContainerView child whose ID is 300. The child requests the host's available width and height.

@MainActor
func fragmentHost() -> FrameLayout {
    FrameLayout {
        FragmentContainerView(id: 300)
            .width(.matchParent)
            .height(.matchParent)
    }
}

Request a fragment replacement

When the guard passes, this requests a replacement transaction for the container with ID 300. The helper skips transaction setup when the manager reports saved state and checks each optional API result.

@MainActor
func install(_ fragment: Fragment, in activity: FragmentActivity) {
    guard let manager = activity.supportFragmentManager(),
          !manager.isStateSaved(),
          let transaction = manager.beginTransaction(),
          let replacement = transaction.replace(
              containerViewId: 300,
              fragment: fragment
          ),
          replacement.commit() != nil else {
        return
    }
}

commit() schedules the request on the main thread; it does not execute immediately. The source warns that committing after the containing Activity has saved its state throws. The saved-state check is a guard, not a guarantee that the commit succeeds. A non-nil commit ID does not prove execution or display.

Initializers

• init(id: Int32? = nil) creates the container without a content closure.
• init(id: Int32? = nil, @BodyBuilder content: BodyBuilder.SingleView) accepts a builder closure.

Both initializers accept an optional ID. With no explicit ID, the inherited View initializer generates one. Supply an explicit ID when another API needs to target this container by a known value.

Notes

The builder initializer exists, but its declaration alone does not establish that arbitrary ordinary views are compatible as children of a fragment-managed container or that the closure renders fragments. Keep ordinary layout views outside FragmentContainerView.