Android - 在相机上显示网格线

dependencies {
    implementation 'androidx.camera:camera-core:1.0.0-alpha08'
    implementation 'androidx.camera:camera-camera2:1.0.0-alpha08'
}

    android:id="@+id/preview_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

private PreviewView previewView;
private LifecycleOwner lifecycleOwner;
private CameraX cameraX;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    previewView = findViewById(R.id.preview_view);
    lifecycleOwner = this;

    cameraX = new CameraX.Builder()
            .setPreviewView(previewView)
            .build();
    cameraX.bindToLifecycle(lifecycleOwner);
}

private void addGridLines() {
    ShapeDrawable gridLines = new ShapeDrawable();
    Paint paint = gridLines.getPaint();
    paint.setColor(Color.WHITE);
    paint.setStrokeWidth(2);
    paint.setStyle(Paint.Style.STROKE);
    paint.setPathEffect(new DashPathEffect(new float[]{10, 10}, 0));

    Path path = new Path();
    path.moveTo(0, 0);
    path.lineTo(previewView.getWidth(), 0);
    path.lineTo(previewView.getWidth(), previewView.getHeight());
    path.lineTo(0, previewView.getHeight());
    path.close();

    gridLines.setShape(new PathShape(path, previewView.getWidth(), previewView.getHeight()));
    previewView.getOverlay().add(gridLines);
}

private SurfaceView surfaceView;
private Camera camera;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    surfaceView = findViewById(R.id.surface_view);
    surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            camera = Camera.open();
            try {
                camera.setPreviewDisplay(holder);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            Camera.Parameters parameters = camera.getParameters();
            parameters.setPreviewSize(width, height);
            camera.setParameters(parameters);
            camera.startPreview();
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            camera.stopPreview();
            camera.release();
        }
    });
}

private void addGridLines() {
    ShapeDrawable gridLines = new ShapeDrawable();
    Paint paint = gridLines.getPaint();
    paint.setColor(Color.WHITE);
    paint.setStrokeWidth(2);
    paint.setStyle(Paint.Style.STROKE);
    paint.setPathEffect(new DashPathEffect(new float[]{10, 10}, 0));

    Path path = new Path();
    path.moveTo(0, 0);
    path.lineTo(surfaceView.getWidth(), 0);
    path.lineTo(surfaceView.getWidth(), surfaceView.getHeight());
    path.lineTo(0, surfaceView.getHeight());
    path.close();

    gridLines.setShape(new PathShape(path, surfaceView.getWidth(), surfaceView.getHeight()));
    surfaceView.getOverlay().add(gridLines);
}