Chainway C72 UHF RFID Handheld Reader

android {
    defaultConfig {
        // CRITICAL: The Chainway cw-deviceapi JAR bundles 32-bit librscja_deviceapi.so (armeabi-v7a).
        // 64-bit Android crashes with java.lang.UnsatisfiedLinkError without this filter.
        ndk {
            abiFilters.addAll(listOf("armeabi-v7a"))
        }
    }
}

dependencies {
    implementation(files("libs/cw-deviceapi20191022.jar"))
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3")
    implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.7.0")
}

package com.rfidsoftwares.chainway.scanner

import android.os.Bundle
import android.view.KeyEvent
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import com.rscja.deviceapi.RFIDWithUHFUART
import com.rscja.deviceapi.entity.UHFTAGInfo
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.isActive
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext

class ChainwayInventoryActivity : AppCompatActivity() {

    private var mReader: RFIDWithUHFUART? = null
    private var isScanning = false
    private var inventoryJob: Job? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        initRfidHardware()
    }

    private fun initRfidHardware() {
        lifecycleScope.launch(Dispatchers.IO) {
            try {
                mReader = RFIDWithUHFUART.getInstance()
                // Initialize internal UART serial port (/dev/ttyMT2 @ 115200 baud)
                val success = mReader?.init() ?: false
                if (success) {
                    // Mode 3: Set Indian WPC Frequency Mask (865.0 - 867.0 MHz)
                    mReader?.setFrequencyMode(3)
                    // Set Transmit Power to 30 dBm (1.0 Watt)
                    mReader?.setPower(30)
                }
            } catch (e: Exception) {
                e.printStackTrace()
            }
        }
    }

    // Intercept Physical Pistol Grip Trigger (KeyCode 139 or KEYCODE_F4)
    override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
        if (keyCode == 139 || keyCode == KeyEvent.KEYCODE_F4) {
            if (event?.repeatCount == 0 && !isScanning) {
                startScanning()
                return true
            }
        }
        return super.onKeyDown(keyCode, event)
    }

    override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
        if (keyCode == 139 || keyCode == KeyEvent.KEYCODE_F4) {
            stopScanning()
            return true
        }
        return super.onKeyUp(keyCode, event)
    }

    private fun startScanning() {
        if (isScanning || mReader == null) return
        isScanning = true

        inventoryJob = lifecycleScope.launch(Dispatchers.IO) {
            mReader?.startInventoryTag()
            while (isActive && isScanning) {
                val tag: UHFTAGInfo? = mReader?.readTagFromBuffer()
                if (tag != null) {
                    val epc = tag.epc
                    val rssi = tag.rssi
                    withContext(Dispatchers.Main) {
                        // Process decoded tag without freezing UI thread
                        onTagDecoded(epc, rssi)
                    }
                }
            }
        }
    }

    private fun stopScanning() {
        isScanning = false
        inventoryJob?.cancel()
        lifecycleScope.launch(Dispatchers.IO) {
            mReader?.stopInventory()
        }
    }

    private fun onTagDecoded(epc: String, rssi: String) {
        // Feed into de-duplication cache or SQLite offline database
    }

    override fun onDestroy() {
        super.onDestroy()
        stopScanning()
        // CRITICAL: Always free serial lock to allow other services to access COM port
        mReader?.free()
    }
}