如何设置变焦android摄像头vision.barcode-scanner接口

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Rect;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CaptureRequest;
import android.os.Bundle;
import android.util.Log;
import android.util.Range;
import android.view.Surface;
import android.view.TextureView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import java.util.Arrays;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_CAMERA_PERMISSION = 200;
    private static final String TAG = "CameraZoomExample";

    private TextureView textureView;
    private CameraManager cameraManager;
    private String cameraId;
    private CameraDevice cameraDevice;
    private CameraCaptureSession cameraCaptureSession;
    private CaptureRequest.Builder captureRequestBuilder;
    private Rect zoomRect;

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

        textureView = findViewById(R.id.textureView);
        cameraManager = (CameraManager) getSystemService(CAMERA_SERVICE);

        textureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
            @Override
            public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int width, int height) {
                openCamera();
            }

            @Override
            public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int width, int height) {
                // Handle surface texture size change if needed
            }

            @Override
            public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
                return false;
            }

            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
                // Handle surface texture update if needed
            }
        });
    }

    private void openCamera() {
        try {
            String[] cameraIds = cameraManager.getCameraIdList();
            if (cameraIds.length == 0) {
                Toast.makeText(this, "No camera available", Toast.LENGTH_SHORT).show();
                return;
            }
            cameraId = cameraIds[0];

            if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
                return;
            }

            cameraManager.openCamera(cameraId, new CameraDevice.StateCallback() {
                @Override
                public void onOpened(@NonNull CameraDevice camera) {
                    cameraDevice = camera;
                    createCameraPreviewSession();
                }

                @Override
                public void onDisconnected(@NonNull CameraDevice camera) {
                    camera.close();
                    cameraDevice = null;
                }

                @Override
                public void onError(@NonNull CameraDevice camera, int error) {
                    camera.close();
                    cameraDevice = null;
                    Toast.makeText(MainActivity.this, "Camera open failed", Toast.LENGTH_SHORT).show();
                }
            }, null);
        } catch (CameraAccessException e) {
            Log.e(TAG, "Failed to open camera", e);
            Toast.makeText(this, "Failed to open camera", Toast.LENGTH_SHORT).show();
        }
    }

    private void createCameraPreviewSession() {
        try {
            SurfaceTexture surfaceTexture = textureView.getSurfaceTexture();
            surfaceTexture.setDefaultBufferSize(textureView.getWidth(), textureView.getHeight());
            Surface surface = new Surface(surfaceTexture);

            captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            captureRequestBuilder.addTarget(surface);

            cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
                @Override
                public void onConfigured(@NonNull CameraCaptureSession session) {
                    if (cameraDevice == null) {
                        return;
                    }

                    cameraCaptureSession = session;
                    try {
                        session.setRepeatingRequest(captureRequestBuilder.build(), null, null);
                        setZoomLevel(2.0f); // Set zoom level here
                    } catch (CameraAccessException e) {
                        Log.e(TAG, "Failed to start camera preview", e);
                        Toast.makeText(MainActivity.this, "Failed to start camera preview", Toast.LENGTH_SHORT).show();
                    }
                }

                @Override
                public void onConfigureFailed(@NonNull CameraCaptureSession session) {
                    Toast.makeText(MainActivity.this, "Failed to configure camera", Toast.LENGTH_SHORT).show();
                }
            }, null);
        } catch (CameraAccessException e) {
            Log.e(TAG, "Failed to create camera preview session", e);
            Toast.makeText(this, "Failed to create camera preview session", Toast.LENGTH_SHORT).show();
        }
    }

    private void setZoomLevel(float zoomLevel) {
        try {
            CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
            float maxZoom = characteristics.get(CameraCharacteristics.SCALER_AVAILABLE_MAX_DIGITAL_ZOOM);
            Rect sensorRect = characteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);

            float zoomRatio = 1.0f + (maxZoom - 1.0f) * zoomLevel;
            int centerX = sensorRect.width() / 2;
            int centerY = sensorRect.height() / 2;
            int deltaX = (int) (0.5f * sensorRect.width() / zoomRatio);
            int deltaY = (int) (0.5f * sensorRect.height() / zoomRatio);

            zoomRect = new Rect(centerX - deltaX, centerY - deltaY, centerX + deltaX, centerY + deltaY);
            captureRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomRect);
            cameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), null, null);
        } catch (CameraAccessException e) {
            Log.e(TAG, "Failed to set zoom level", e);
            Toast.makeText(this, "Failed to set zoom level", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        closeCamera();
    }

    private void closeCamera() {
        if (cameraCaptureSession != null) {
            cameraCaptureSession.close();
            cameraCaptureSession = null;
        }
        if (cameraDevice != null) {
            cameraDevice.close();
            cameraDevice = null;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == REQUEST_CAMERA_PERMISSION) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                openCamera();
            } else {
                Toast.makeText(this, "Camera permission denied", Toast.LENGTH_SHORT).show();
            }
        }
    }
}