xml - CameraX 和条码扫描仪 - 条码扫描仪无法读取
问题描述
我目前正在尝试使用 CameraX API 和 ML Kit 进行条码扫描。当我将相机对准二维码时,我没有从 PreviewView 收到任何数据。让我与您分享我的代码,我想我已经很接近了,但遗憾的是无法弄清楚。:/ 我正在使用预览和图像分析案例
带有 ImageAnalysis.Analyser 的 MainActivity
class MainActivity : AppCompatActivity() {
private lateinit var outputDirectory: File
private lateinit var cameraExecutor: ExecutorService
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
outputDirectory = getOutputDirectory()
cameraExecutor = Executors.newSingleThreadExecutor()
// Request camera permissions
if (allPermissionsGranted()) {
startCamera()
} else {
ActivityCompat.requestPermissions(
this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS
)
}
}
private fun getOutputDirectory(): File {
val mediaDir = externalMediaDirs.firstOrNull()?.let {
File(it, resources.getString(R.string.app_name)).apply { mkdirs() }
}
return if (mediaDir != null && mediaDir.exists())
mediaDir else filesDir
}
override fun onRequestPermissionsResult(
requestCode: Int, permissions: Array<String>, grantResults:
IntArray
) {
if (requestCode == REQUEST_CODE_PERMISSIONS) {
if (allPermissionsGranted()) {
startCamera()
} else {
Toast.makeText(
this,
"Permissions not granted by the user.",
Toast.LENGTH_SHORT
).show()
finish()
}
}
}
private fun allPermissionsGranted() = REQUIRED_PERMISSIONS.all {
ContextCompat.checkSelfPermission(
baseContext, it
) == PackageManager.PERMISSION_GRANTED
}
private fun startCamera() {
val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
cameraProviderFuture.addListener({
val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()
// Preview
val preview = Preview.Builder()
.build()
.also {
it.setSurfaceProvider(previewView.surfaceProvider)
}
// Image Analyzer
val imageAnalyzer = ImageAnalysis.Builder()
.build()
.also {
it.setAnalyzer(cameraExecutor, MyImageAnalyser())
}
val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
try {
cameraProvider.unbindAll()
cameraProvider.bindToLifecycle(
this, cameraSelector, preview, imageAnalyzer
)
} catch (exc: Exception) {
Log.e(Constants.TAG, "Use case binding failed", exc)
}
}, ContextCompat.getMainExecutor(this))
}
inner class MyImageAnalyser : ImageAnalysis.Analyzer {
@SuppressLint("UnsafeExperimentalUsageError")
override fun analyze(imageProxy: ImageProxy) {
val mediaImage = imageProxy.image
if (mediaImage != null) {
val image =
InputImage.fromMediaImage(mediaImage, imageProxy.imageInfo.rotationDegrees)
initializeBarcodeScanner(image)
}
}
private fun initializeBarcodeScanner(inputImage: InputImage) {
val options = BarcodeScannerOptions.Builder()
.setBarcodeFormats(
Barcode.QR_CODE,
Barcode.WIFI,
Barcode.URL
)
.build()
val scanner = BarcodeScanning.getClient(options)
scanner.process(inputImage)
.addOnSuccessListener { barcodes ->
for (barcode in barcodes) {
val bounds = barcode.boundingBox
val corners = barcode.cornerPoints
val rawValue = barcode.rawValue
Log.d("BARCODE", barcode.valueType.toString())
when (barcode.valueType) {
Barcode.WIFI -> {
val ssid = barcode.wifi!!.ssid
val password = barcode.wifi!!.password
val type = barcode.wifi!!.encryptionType
Log.d("BARCODE", ssid.toString())
Log.d("BARCODE", password.toString())
Log.d("BARCODE", type.toString())
}
Barcode.URL -> {
val title = barcode.url!!.title
val url = barcode.url!!.url
Log.d("BARCODE", title.toString())
Log.d("BARCODE", url.toString())
}
Barcode.QR_CODE -> {
Log.d("BARCODE", barcode.rawValue.toString())
}
else -> {
Log.d("BARCODE", "Else")
}
}
}
}
.addOnFailureListener {
Log.d("BARCODE", it.message.toString())
}
}
}
override fun onDestroy() {
super.onDestroy()
cameraExecutor.shutdown()
}
}
常量.kt
class Constants {
companion object {
const val TAG = "CameraXBasic"
const val REQUEST_CODE_PERMISSIONS = 10
val REQUIRED_PERMISSIONS = arrayOf(Manifest.permission.CAMERA)
}
}
activity_main.xml
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.camera.view.PreviewView
android:id="@+id/previewView"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/textView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</androidx.camera.view.PreviewView>
<TextView
android:id="@+id/textView"
android:layout_width="0dp"
android:layout_height="200dp"
android:layout_marginStart="20dp"
android:layout_marginEnd="20dp"
android:text="TextView"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
依赖项
// Use this dependency to bundle the model with your app
implementation 'com.google.mlkit:barcode-scanning:16.0.3'
def camerax_version = "1.0.0-beta10"
// CameraX core library using camera2 implementation
implementation "androidx.camera:camera-camera2:$camerax_version"
// CameraX Lifecycle Library
implementation "androidx.camera:camera-lifecycle:$camerax_version"
// CameraX View class
implementation "androidx.camera:camera-view:1.0.0-alpha17"
解决方案
分析仪接收到的每张图像都必须先关闭,然后才能接收新图像。文档说:
完成后关闭图像是应用程序的责任。如果图像未关闭,则可能会阻止生成更多图像
关闭图像是通过 实现的ImageProxy.close()
。由于您使用的是 MLKit,因此您可以添加一个任务完成侦听器,并关闭其中的图像。当任务(图像处理)成功完成或出现错误时,将调用侦听器。
Task.addOnSuccessListener { barcodes -> ... }
.addOnFailureListener { exception -> }
.addOnCompleteListener { imageProxy.close() }
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