scanner
This commit is contained in:
agra
@@ -52,3 +52,15 @@ android {
|
||||
jvmTarget = '1.8'
|
||||
}
|
||||
}
|
||||
|
||||
dependencies {
|
||||
// CameraX for scanner preview + frame analysis. Pinned to a stable
|
||||
// train; the `view` module pulls in the rest transitively.
|
||||
def cameraxVersion = '1.3.4'
|
||||
implementation "androidx.camera:camera-core:$cameraxVersion"
|
||||
implementation "androidx.camera:camera-camera2:$cameraxVersion"
|
||||
implementation "androidx.camera:camera-lifecycle:$cameraxVersion"
|
||||
implementation "androidx.camera:camera-view:$cameraxVersion"
|
||||
// Pure-Kotlin/Java QR decoder. ~470 KB jar, no Play Services dep.
|
||||
implementation 'com.google.zxing:core:3.5.3'
|
||||
}
|
||||
|
||||
243
android/src/main/kotlin/io/swipelab/ux/ScannerPlugin.kt
Normal file
243
android/src/main/kotlin/io/swipelab/ux/ScannerPlugin.kt
Normal file
@@ -0,0 +1,243 @@
|
||||
package io.swipelab.ux
|
||||
|
||||
import android.Manifest
|
||||
import android.app.Activity
|
||||
import android.content.Context
|
||||
import android.content.pm.PackageManager
|
||||
import android.os.Handler
|
||||
import android.os.Looper
|
||||
import android.view.View
|
||||
import androidx.camera.core.CameraSelector
|
||||
import androidx.camera.core.ImageAnalysis
|
||||
import androidx.camera.core.ImageProxy
|
||||
import androidx.camera.core.Preview
|
||||
import androidx.camera.lifecycle.ProcessCameraProvider
|
||||
import androidx.camera.view.PreviewView
|
||||
import androidx.core.app.ActivityCompat
|
||||
import androidx.core.content.ContextCompat
|
||||
import androidx.lifecycle.LifecycleOwner
|
||||
import com.google.zxing.BarcodeFormat
|
||||
import com.google.zxing.BinaryBitmap
|
||||
import com.google.zxing.DecodeHintType
|
||||
import com.google.zxing.MultiFormatReader
|
||||
import com.google.zxing.PlanarYUVLuminanceSource
|
||||
import com.google.zxing.common.HybridBinarizer
|
||||
import io.flutter.embedding.engine.plugins.FlutterPlugin
|
||||
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding
|
||||
import io.flutter.plugin.common.EventChannel
|
||||
import io.flutter.plugin.common.MethodCall
|
||||
import io.flutter.plugin.common.MethodChannel
|
||||
import io.flutter.plugin.common.StandardMessageCodec
|
||||
import io.flutter.plugin.platform.PlatformView
|
||||
import io.flutter.plugin.platform.PlatformViewFactory
|
||||
import java.util.concurrent.Executors
|
||||
|
||||
class ScannerPlugin :
|
||||
NativePlugin,
|
||||
MethodChannel.MethodCallHandler {
|
||||
companion object {
|
||||
// Single shared event sink — the app only ever shows one scanner
|
||||
// at a time (settings → scan), so collapsing to one channel keeps
|
||||
// the platform-view factory free of per-view registrar wiring.
|
||||
@JvmStatic
|
||||
@Volatile
|
||||
var eventSink: EventChannel.EventSink? = null
|
||||
|
||||
private val mainHandler = Handler(Looper.getMainLooper())
|
||||
|
||||
/// EventChannel methods are @UiThread; the analyzer runs on a
|
||||
/// background pool. Bounce through the main looper.
|
||||
@JvmStatic
|
||||
fun emit(code: String) {
|
||||
mainHandler.post { eventSink?.success(code) }
|
||||
}
|
||||
|
||||
private const val PERMISSION_REQUEST_CODE = 0xC1A0
|
||||
}
|
||||
|
||||
private var methodChannel: MethodChannel? = null
|
||||
private var eventChannel: EventChannel? = null
|
||||
private var lifecycleOwner: LifecycleOwner? = null
|
||||
private var activity: Activity? = null
|
||||
private var activityBinding: ActivityPluginBinding? = null
|
||||
private var pendingPermissionResult: MethodChannel.Result? = null
|
||||
|
||||
override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
|
||||
val ec = EventChannel(binding.binaryMessenger, "ux/scanner/events")
|
||||
ec.setStreamHandler(object : EventChannel.StreamHandler {
|
||||
override fun onListen(arguments: Any?, events: EventChannel.EventSink?) {
|
||||
eventSink = events
|
||||
}
|
||||
|
||||
override fun onCancel(arguments: Any?) {
|
||||
eventSink = null
|
||||
}
|
||||
})
|
||||
eventChannel = ec
|
||||
|
||||
val mc = MethodChannel(binding.binaryMessenger, "ux/scanner")
|
||||
mc.setMethodCallHandler(this)
|
||||
methodChannel = mc
|
||||
|
||||
binding.platformViewRegistry.registerViewFactory(
|
||||
"ux/scanner",
|
||||
ScannerViewFactory { lifecycleOwner },
|
||||
)
|
||||
}
|
||||
|
||||
override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
|
||||
eventChannel?.setStreamHandler(null)
|
||||
eventChannel = null
|
||||
eventSink = null
|
||||
methodChannel?.setMethodCallHandler(null)
|
||||
methodChannel = null
|
||||
}
|
||||
|
||||
override fun onAttachedToActivity(binding: ActivityPluginBinding) {
|
||||
// The host app's MainActivity is a `FlutterActivity`, which extends
|
||||
// `LifecycleOwner` indirectly via `androidx.activity.ComponentActivity`.
|
||||
lifecycleOwner = binding.activity as? LifecycleOwner
|
||||
activity = binding.activity
|
||||
activityBinding = binding
|
||||
binding.addRequestPermissionsResultListener { code, _, results ->
|
||||
if (code != PERMISSION_REQUEST_CODE) return@addRequestPermissionsResultListener false
|
||||
val granted = results.isNotEmpty() &&
|
||||
results[0] == PackageManager.PERMISSION_GRANTED
|
||||
pendingPermissionResult?.success(granted)
|
||||
pendingPermissionResult = null
|
||||
true
|
||||
}
|
||||
}
|
||||
|
||||
override fun onDetachedFromActivity() {
|
||||
lifecycleOwner = null
|
||||
activity = null
|
||||
activityBinding = null
|
||||
// If the activity tears down with a request still in flight, settle
|
||||
// it cleanly rather than leaking the Result.
|
||||
pendingPermissionResult?.success(false)
|
||||
pendingPermissionResult = null
|
||||
}
|
||||
|
||||
override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
|
||||
when (call.method) {
|
||||
"requestPermission" -> handleRequestPermission(result)
|
||||
else -> result.notImplemented()
|
||||
}
|
||||
}
|
||||
|
||||
private fun handleRequestPermission(result: MethodChannel.Result) {
|
||||
val act = activity
|
||||
?: return result.error("no_activity", "plugin not attached to an activity", null)
|
||||
val granted = ContextCompat.checkSelfPermission(
|
||||
act, Manifest.permission.CAMERA,
|
||||
) == PackageManager.PERMISSION_GRANTED
|
||||
if (granted) return result.success(true)
|
||||
if (pendingPermissionResult != null) {
|
||||
return result.error("in_progress", "another permission request is in flight", null)
|
||||
}
|
||||
pendingPermissionResult = result
|
||||
ActivityCompat.requestPermissions(
|
||||
act,
|
||||
arrayOf(Manifest.permission.CAMERA),
|
||||
PERMISSION_REQUEST_CODE,
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
private class ScannerViewFactory(
|
||||
private val lifecycleOwnerProvider: () -> LifecycleOwner?,
|
||||
) : PlatformViewFactory(StandardMessageCodec.INSTANCE) {
|
||||
override fun create(context: Context, viewId: Int, args: Any?): PlatformView {
|
||||
return ScannerPlatformView(context, lifecycleOwnerProvider())
|
||||
}
|
||||
}
|
||||
|
||||
private class ScannerPlatformView(
|
||||
context: Context,
|
||||
private val lifecycleOwner: LifecycleOwner?,
|
||||
) : PlatformView {
|
||||
// COMPATIBLE forces a TextureView under the hood; SurfaceView (the
|
||||
// PERFORMANCE default) is its own window and won't composite under
|
||||
// Flutter overlays in hybrid composition.
|
||||
private val previewView = PreviewView(context).apply {
|
||||
implementationMode = PreviewView.ImplementationMode.COMPATIBLE
|
||||
}
|
||||
private val analysisExecutor = Executors.newSingleThreadExecutor()
|
||||
private val reader: MultiFormatReader = MultiFormatReader().apply {
|
||||
setHints(
|
||||
mapOf(
|
||||
DecodeHintType.POSSIBLE_FORMATS to listOf(BarcodeFormat.QR_CODE),
|
||||
),
|
||||
)
|
||||
}
|
||||
|
||||
init {
|
||||
if (lifecycleOwner != null) bindCamera(context, lifecycleOwner)
|
||||
}
|
||||
|
||||
private fun bindCamera(context: Context, lifecycleOwner: LifecycleOwner) {
|
||||
val cameraProviderFuture = ProcessCameraProvider.getInstance(context)
|
||||
cameraProviderFuture.addListener({
|
||||
val cameraProvider = cameraProviderFuture.get()
|
||||
|
||||
val preview = Preview.Builder().build().also {
|
||||
it.setSurfaceProvider(previewView.surfaceProvider)
|
||||
}
|
||||
|
||||
val analysis = ImageAnalysis.Builder()
|
||||
.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
|
||||
.build()
|
||||
.also { it.setAnalyzer(analysisExecutor, ::analyze) }
|
||||
|
||||
try {
|
||||
cameraProvider.unbindAll()
|
||||
cameraProvider.bindToLifecycle(
|
||||
lifecycleOwner,
|
||||
CameraSelector.DEFAULT_BACK_CAMERA,
|
||||
preview,
|
||||
analysis,
|
||||
)
|
||||
} catch (_: Throwable) {
|
||||
// Permission denied / camera unavailable — preview stays
|
||||
// black. Caller surfaces a fallback (e.g. paste-hex).
|
||||
}
|
||||
}, androidx.core.content.ContextCompat.getMainExecutor(context))
|
||||
}
|
||||
|
||||
private fun analyze(image: ImageProxy) {
|
||||
try {
|
||||
val plane = image.planes.firstOrNull() ?: return
|
||||
val buffer = plane.buffer
|
||||
val bytes = ByteArray(buffer.remaining()).also { buffer.get(it) }
|
||||
val source = PlanarYUVLuminanceSource(
|
||||
bytes,
|
||||
plane.rowStride,
|
||||
image.height,
|
||||
0, 0,
|
||||
image.width, image.height,
|
||||
false,
|
||||
)
|
||||
val bitmap = BinaryBitmap(HybridBinarizer(source))
|
||||
val result = try {
|
||||
reader.decode(bitmap)
|
||||
} catch (_: Throwable) {
|
||||
null
|
||||
} finally {
|
||||
reader.reset()
|
||||
}
|
||||
val text = result?.text
|
||||
if (!text.isNullOrEmpty()) {
|
||||
ScannerPlugin.emit(text)
|
||||
}
|
||||
} finally {
|
||||
image.close()
|
||||
}
|
||||
}
|
||||
|
||||
override fun getView(): View = previewView
|
||||
|
||||
override fun dispose() {
|
||||
analysisExecutor.shutdown()
|
||||
}
|
||||
}
|
||||
@@ -9,6 +9,7 @@ class UxPlugin : FlutterPlugin, ActivityAware {
|
||||
KeyboardPlugin(),
|
||||
SensorPlugin(),
|
||||
FilePlugin(),
|
||||
ScannerPlugin(),
|
||||
)
|
||||
|
||||
override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) =
|
||||
|
||||
Reference in New Issue
Block a user