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Platform adapters

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Nutrient Flutter SDK includes platform adapters for extending viewer behavior. Platform adapters give you direct access to the native Nutrient PDF SDKs on Android, iOS, and Web when the cross-platform API doesn’t cover your use case.

Every NutrientDocumentView uses an adapter as its controller. This means one object gives you access to the cross-platform API and the native SDK.

Most apps only need the built-in controller. Use the cross-platform API on controller.document and controller.events for document operations and events that work the same way across platforms. Subclass a platform adapter only when you need native behavior that the cross-platform API doesn’t expose.

Starting with Nutrient Flutter SDK 6, document, annotation, form, bookmark, and event operations use the same bindings architecture. Use platform adapters to access native APIs instead of raw MethodChannel calls or the generated Pigeon bridge.

When you need an adapter

Use this table to choose the right approach for your app:

You need…Use
To view a document and use the cross-platform API — annotations, bookmarks, forms, save/export, the event streamA bare NutrientDocumentView(...) — no adapter
Custom native behavior — typed native handles, custom lifecycle hooks, your own controller methodsA registered controller (addAdapterClass<T> + NutrientDocumentView<T>)
To hold or drive the controller yourself, or run multiple independent views at onceA per-view adapter: instance you create and dispose of

Native bindings per platform

A platform adapter subclasses the base class for its target platform and gives you typed access to the underlying native SDK:

  • Android — Use AndroidAdapter, backed by JNI bindings from the jni package.
  • iOS — Use IOSAdapter, backed by Objective-C bindings from the objective_c package.
  • Web — Use NutrientWebAdapter, backed by JavaScript interop with dart:js_interop.

The adapter is the controller, so one object gives you access to the cross-platform API and native handles.

Architecture

NutrientDocumentView resolves a controller — the platform adapter — that bridges to the native SDK on each platform.

Platform adapters architecture

Each adapter extends its platform base class, receives lifecycle callbacks, implements your shared controller interface, and exposes the native SDK objects.

Adapter pattern

Next steps

Continue with these guides:

  • Refer to the getting started guide to display a document and create your first adapter.
  • Refer to the usage patterns guide for native configuration, controller operations, and native events.
  • Refer to the platform imports guide to handle platform-specific imports.