Chainway's Obsolete SDK API: Migration Notes

Every Chainway UHF handheld — C72, C71, C66, C5, and others in the same UART-based reader family — ships sample code built around RFIDWithUHF. Every one of those SDK builds also marks that same class deprecated, pointing at RFIDWithUHFUART as the forward-compatible replacement. Almost no integrator reads far enough into the SDK's Javadoc-equivalent comments to notice.

What the vendor docs don't tell you

The deprecation isn't a rumor or a forum post — it's an annotation in the SDK's own class definition. It just never made it into the sample apps that most integrators actually copy from.

Why this matters for production

A demo app that works during a five-minute vendor evaluation and a production deployment that runs eight hours a day for a year are different reliability bars. The obsolete API's untested edge cases are exactly the paths that only surface under sustained production load — buffer overflow during a long inventory session, reconnect behavior after the device sleeps, and UART port contention across app restarts.

Migration map

Migration steps

Migrating a live app off RFIDWithUHF is mechanical if the reader access is already isolated behind a wrapper class, and a larger refactor if it isn't.

Copy// Before
class LegacyRfidManager(private val context: Context) {
    private val reader = RFIDWithUHF()
 
    fun start() {
        reader.init(context)
        reader.startScan()
    }
 
    fun read(): TagInfo? = reader.uhfGetTagInfo()
 
    fun stop() {
        reader.stopScan()
        reader.close()
    }
}
 
// After
class RfidManager {
    private val reader = RFIDWithUHFUART.getInstance()
 
    fun start(): Boolean {
        val ok = reader.init()
        if (ok) reader.startInventoryTag()
        return ok
    }
 
    fun read(): UHFTagInfo? = reader.readTagFromBuffer()
 
    fun stop() {
        reader.stopInventory()
    }
 
    fun release() {
        reader.free()
    }
}

1. Isolate all direct RFIDWithUHF calls behind a single manager class if they aren't already — this is the highest-leverage refactor for the migration and pays for itself on the next SDK bump too.
2. Swap the class reference and method names per the migration map above.
3. Add an explicit release()/free() call to the hosting Activity or Fragment's onPause(). The old .close() call was more forgiving about when it ran; .free() on the UART class needs to run before the process can be backgrounded safely.
4. Re-test the trigger-key integration path specifically — keycode handling didn't change, but any code that assumed RFIDWithUHF's buffer behavior around rapid trigger press/release cycles should be re-verified against the UART class's buffer semantics.

Common errors