kotlin 如何检测视图内的条形码角点？

我的条形码阅读器运行良好，但我希望用户只能扫描查看区域内的条形码以进行检测。我为此编写了代码。我可以获得扫描的条形码的cornerPoints，但我无法意识到它是否在我的检测视图内。我无法看到在调试模式下从片段传递到BarcodeAnalyzer类的view的rect值。我不I don“我不知道要做到这一点是否有问题。

BarcodeReaderFragment.kt

val imageAnalyzer = ImageAnalysis.Builder()
                                                 .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
                                                 .build()

                                                 .also {
                                                     val rect = Rect()
                                                     binding.viewFocusArea.getGlobalVisibleRect(rect)
                                                     it.setAnalyzer(
                                                         cameraExecutor, BarcodeAnalyzer(
                                                             rect,
                                                             ::barcodeListener
                                                         )
                                                     )
                                                 }

BarcodeAnalyzer.kt

class BarcodeAnalyzer(
    private val rectArea: Rect,
    private val barcodeListener: (barcode: String) -> Unit
) : ImageAnalysis.Analyzer {
   
.addOnCompleteListener {
                image.close()
                if (it.isSuccessful) {
                    val barcodes = it.result as List<Barcode>
                    // Task completed successfully
                    for (barcode in barcodes) {

                            val cornerTL = barcode.cornerPoints?.get(0)
                            val cornerTR = barcode.cornerPoints?.get(1)
                            val cornerBL = barcode.cornerPoints?.get(2)
                            val cornerBR = barcode.cornerPoints?.get(3)

                            cornerTL?.let { topLeft ->
                                cornerTR?.let { topRight ->
                                    cornerBR?.let { bottomRight ->
                                        cornerBL?.let { bottomLeft ->
                                            if (rectArea.contains(topLeft) && rectArea.contains(topRight) && rectArea.contains(bottomRight) && rectArea.contains(
                                                    bottomLeft
                                                )
                                            ) {
                                                barcodeListener(barcode.rawValue ?: "")
                                            }
                                        }

}

fragment_barcode_reader.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <androidx.camera.view.PreviewView
        android:id="@+id/preview_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0" />

    <View
        android:id="@+id/viewRightTopVCorner"
        android:layout_width="12dp"
        android:layout_height="1dp"
        android:layout_marginEnd="-4dp"
        android:layout_marginBottom="5dp"
        android:background="@color/white"
        app:layout_constraintBottom_toTopOf="@+id/viewFocusArea"
        app:layout_constraintEnd_toEndOf="@+id/viewFocusArea" />

    <View
        android:id="@+id/viewRightTopHCorner"
        android:layout_width="1dp"
        android:layout_height="12dp"
        android:background="@color/white"
        app:layout_constraintEnd_toEndOf="@+id/viewRightTopVCorner"
        app:layout_constraintTop_toBottomOf="@+id/viewRightTopVCorner" />

    <View
        android:id="@+id/viewRightBottomVCorner"
        android:layout_width="12dp"
        android:layout_height="1dp"
        android:layout_marginTop="5dp"
        android:layout_marginEnd="-4dp"
        android:background="@color/white"
        app:layout_constraintEnd_toEndOf="@+id/viewFocusArea"
        app:layout_constraintTop_toBottomOf="@+id/viewFocusArea" />

    <View
        android:id="@+id/viewRightBottomHCorner"
        android:layout_width="1dp"
        android:layout_height="12dp"
        android:background="@color/white"
        app:layout_constraintEnd_toEndOf="@+id/viewRightBottomVCorner"
        app:layout_constraintBottom_toTopOf="@+id/viewRightBottomVCorner" />

    <View
        android:id="@+id/viewLeftBottomVCorner"
        android:layout_width="12dp"
        android:layout_height="1dp"
        android:layout_marginStart="-4dp"
        android:layout_marginTop="5dp"
        android:background="@color/white"
        app:layout_constraintStart_toStartOf="@+id/viewFocusArea"
        app:layout_constraintTop_toBottomOf="@+id/viewFocusArea" />

    <View
        android:id="@+id/viewLeftBottomHCorner"
        android:layout_width="1dp"
        android:layout_height="12dp"
        android:background="@color/white"
        app:layout_constraintBottom_toTopOf="@+id/viewLeftBottomVCorner"
        app:layout_constraintStart_toStartOf="@+id/viewLeftBottomVCorner" />

    <View
        android:id="@+id/viewLeftTopVCorner"
        android:layout_width="12dp"
        android:layout_height="1dp"
        android:layout_marginStart="-4dp"
        android:layout_marginBottom="5dp"
        android:background="@color/white"
        app:layout_constraintBottom_toTopOf="@+id/viewFocusArea"
        app:layout_constraintStart_toStartOf="@+id/viewFocusArea" />

    <View
        android:id="@+id/viewLeftTopHCorner"
        android:layout_width="1dp"
        android:layout_height="12dp"
        android:background="@color/white"
        app:layout_constraintTop_toBottomOf="@+id/viewLeftTopVCorner"
        app:layout_constraintStart_toStartOf="@+id/viewLeftTopVCorner" />

    <View
        android:id="@+id/viewFocusArea"
        android:layout_width="0dp"
        android:layout_height="101dp"
        android:layout_marginStart="48dp"
        android:layout_marginTop="35dp"
        android:layout_marginEnd="47dp"
        android:background="#00FFFFFF"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="@+id/preview_view"
        app:layout_constraintTop_toBottomOf="@+id/txtBarcodeScan" />

    <View
        android:id="@+id/shadow_top"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginBottom="-4dp"
        android:background="#80000000"
        app:layout_constraintBottom_toTopOf="@+id/viewFocusArea"
        app:layout_constraintEnd_toStartOf="@+id/shadow_right"
        app:layout_constraintStart_toEndOf="@+id/shadow_left"
        app:layout_constraintTop_toTopOf="parent"
        tools:visibility="invisible" />

    <View
        android:id="@+id/shadow_bottom"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginTop="-4dp"
        android:background="#80000000"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/shadow_right"
        app:layout_constraintStart_toEndOf="@+id/shadow_left"
        app:layout_constraintTop_toBottomOf="@+id/viewFocusArea"
        tools:visibility="invisible" />

    <View
        android:id="@+id/shadow_left"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginEnd="-4dp"
        android:background="#80000000"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/viewFocusArea"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:visibility="invisible" />

    <View
        android:id="@+id/shadow_right"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="-4dp"
        android:background="#80000000"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="@+id/preview_view"
        app:layout_constraintStart_toEndOf="@+id/viewFocusArea"
        app:layout_constraintTop_toTopOf="parent"
        tools:visibility="invisible" />

    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="30dp"
        app:layout_constraintEnd_toEndOf="@+id/preview_view"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_identity_hexagon" />

    <TextView
        android:id="@+id/txtBarcodeScan"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Lütfen fiyatını öğrenmek istediğin \nürünün barkodunu okut"
        android:textColor="@color/white"
        android:gravity="center"
        android:fontFamily="@font/poppins_regular"
        android:textSize="16sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/image" />

    <com.google.android.material.button.MaterialButton
        android:id="@+id/btnChangeShop"
        style="@style/Widget.MaterialComponents.Button.TextButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="55dp"
        android:backgroundTint="@color/dull_orange"
        android:fontFamily="@font/poppins_semibold"
        android:insetTop="0dp"
        android:insetBottom="0dp"
        android:letterSpacing="0"
        app:cornerRadius="4dp"
        android:paddingVertical="15dp"
        android:text="@string/click_to_change_shop"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="14sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

以防你还需要。
我编写了一个代码片段，使用Java版本的代码片段测试imageProxy坐标到预览坐标的转换，代码片段位于：https://developer.android.com/training/camerax/transform-output.
当条形码视图进入位于height = previewView. getHeight（）/5和width = preview. getWidth（）/2的矩形视图时，检测到条形码。
结论：检测工作得非常好。

@SuppressLint("SetTextI18n")
    @Override
    public void analyze(@NonNull ImageProxy imageProxy) {

        Image mediaImage = imageProxy.getImage();
        int rotation = imageProxy.getImageInfo().getRotationDegrees();

        if (mediaImage != null) {
            InputImage image =
                    InputImage.fromMediaImage(mediaImage, rotation);

            scanner.process(image)
                    .addOnSuccessListener(barcodes -> {
                        for (Barcode barcode : barcodes) {
                            processBarcodeResult(barcode, imageProxy);
                        }
                    })
                    .addOnCompleteListener(results -> imageProxy.close());
        }
    }

    static void processBarcodeResult(Barcode barcode, ImageProxy imageProxy) {
// xp and yp are the coordinates of the center of the preview rectangle
        int xp = previewView.getWidth() >> 1;
        int yp = previewView.getHeight() / 5;
// xOffset and yOffset are threshold for detecting
// that the barcode view enters the preview rectangle        
        int xOffset = (int) (barcode.getBoundingBox().width() / 2.5f);
        int yOffset = (int) (barcode.getBoundingBox().height() / 2.5f);
// xb and yb are the coordinates of the center 
// of the barcode boundingbox.
        int xb = barcode.getBoundingBox().centerX();
        int yb = barcode.getBoundingBox().centerY();
// matrix transforms the imageProxy coordinates in the
// preview coordinates        
        Matrix matrix = getMappingMatrix(imageProxy);
        float[] xyb = new float[]{xb, yb};
        
        matrix.mapPoints(xyb);// transforms the bounding box center 
                              // coordinates
        xb = (int) xyb[0];
        yb = (int) xyb[1];

        if (xb > xp - xOffset && xb < xp + xOffset && yb > yp - yOffset && yb < yp + yOffset) {
            format.setText(barcode.getFormat() + "");
            code.setText(barcode.getRawValue());
// code and format are 2 TextView in the mainactivity layout.
        }

    }

    static Matrix getMappingMatrix(ImageProxy imageProxy) {
        Rect cropRect = imageProxy.getCropRect();
        Matrix matrix = new Matrix();

        // A float array of the source vertices (crop rect) in clockwise order.
        float[] source = {cropRect.left, cropRect.top, cropRect.right,
                cropRect.top, cropRect.right, cropRect.bottom, cropRect.left,
                cropRect.bottom
        };

        // A float array of the destination vertices in clockwise order.
        float[] destination = {0f, 0f, previewView.getWidth(), 0f,
                previewView.getWidth(), previewView.getHeight(), 0f,
                previewView.getHeight()
        };

        // The destination vertexes need to be shifted based on rotation degrees.
        // The rotation degree represents the clockwise rotation needed to correct
        // the image.

        // Each vertex is represented by 2 float numbers in the vertices array.
        int vertexSize = 2;
        // The destination needs to be shifted 1 vertex for every 90° rotation.
        // imageProxy is already rotated => rotationDegrees = 0!
        int rotationDegrees = 0;
        int shiftOffset = rotationDegrees / 90 * vertexSize;

        float[] tempArray = destination.clone();
        for (int toIndex = 0; toIndex < source.length; toIndex++) {
            int fromIndex = (toIndex + shiftOffset) % source.length;
            destination[toIndex] = tempArray[fromIndex];
        }
        matrix.setPolyToPoly(source, 0, destination, 0, 4);
        return matrix;
    }

我假设您希望在条形码进入此ImageView时检测它!
你必须确定这个图像中心的坐标。这些坐标是我在上面的代码片段中使用的xp和yp坐标。

<ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="30dp"
        app:layout_constraintEnd_toEndOf="@+id/preview_view"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_identity_hexagon" />

kotlin 如何检测视图内的条形码角点？

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