MobileReaderSdk class abstract

Unified Flutter façade for the EasyMerchant mobile card readers.

This is the contract that POS applications (FULL and LITE) consume. The Android and iOS native bridges are responsible for implementing it; this file defines the shape of the API, the lifecycle, and the constraints.

Method channels are intentionally not wired up in this branch. The default implementation provided here throws UnimplementedError for every operation; a platform-channel implementation will land in a follow-up branch alongside the matching native bridges.

Lifecycle

initialize(config)          // exactly once per app run
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  v
discoverReaders({timeout})  // returns discovered devices via events
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  v
connect(reader)             // becomes the active reader
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  v
startTransaction(request)   // emits reader events; returns terminal result
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  v
disconnect()                // releases the active reader

cancelTransaction may be called between startTransaction and a terminal event. getStatus may be called at any time.

Architecture constraints

• This SDK captures encrypted card payloads. It never holds the PAN, CVV, or full track data, and never authorizes a payment.
• em-api owns gateway authorization. The SDK forwards the encrypted payload through em-api and reports back whatever em-api returns. The SDK does not synthesize approval or auth codes on its own.
• The POS app owns checkout UX, sale state, tip/tax math, and receipts. The SDK reports events; the POS decides what they mean for the cart.