如何使用Mobile Vision API打开/关闭闪光灯？

问：

我正在使用移动视觉来识别图像上的文本。这几乎是我的MainActivity：

package com.usama.textrecognitionbycamera;

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

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.util.SparseArray;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.TextView;

import com.google.android.gms.vision.CameraSource;
import com.google.android.gms.vision.Detector;
import com.google.android.gms.vision.text.TextBlock;
import com.google.android.gms.vision.text.TextRecognizer;

import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    // welcome ..
    SurfaceView cameraView;
    TextView textView;
    CameraSource cameraSource;

    final int RequestCameraPermission = 1001;


    // 3
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case RequestCameraPermission: {
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                        return;
                    }
                    try {
                        cameraSource.start(cameraView.getHolder());
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }



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

        cameraView = findViewById(R.id.surface_view);
        textView = findViewById(R.id.text_view);


        // 1
        final TextRecognizer textRecognizer = new TextRecognizer.Builder(getApplicationContext()).build();
        if (!textRecognizer.isOperational()) {
            Log.w("MainActivity", "Detected dependence are not found ");
        } else {
            cameraSource = new CameraSource.Builder(getApplicationContext(), textRecognizer)
                    .setFacing(CameraSource.CAMERA_FACING_BACK)
                    .setRequestedPreviewSize(1280, 1024)
                    .setRequestedFps(2.0f)
                    .setAutoFocusEnabled(true)
                    .build();

            // 2
            cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
                @Override
                public void surfaceCreated(SurfaceHolder holder) {
                    try {
                        if (ActivityCompat.checkSelfPermission(getApplicationContext(),Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED){
                            ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.CAMERA},
                                    RequestCameraPermission);
                        }
                        cameraSource.start(cameraView.getHolder());
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }

                @Override
                public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

                }

                @Override
                public void surfaceDestroyed(SurfaceHolder holder) {
                    cameraSource.stop();
                }
            });


            // 4
            textRecognizer.setProcessor(new Detector.Processor<TextBlock>() {
                @Override
                public void release() {

                }

                @Override
                public void receiveDetections(Detector.Detections<TextBlock> detections) {
                    final SparseArray<TextBlock> items = detections.getDetectedItems();
                    if (items.size() != 0 ){
                        textView.post(new Runnable() {
                            @Override
                            public void run() {
                                StringBuilder stringBuilder = new StringBuilder();
                                for (int i = 0 ;i < items.size();i++){
                                    TextBlock item = items.valueAt(i);
                                    stringBuilder.append(item.getValue());
                                    stringBuilder.append("\n");
                                }
                                textView.setText(stringBuilder.toString());
                                Log.d("Text",stringBuilder.toString());
                            }
                        });
                    }
                }
            });
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:padding="16dp"
    tools:context=".MainActivity">

    <SurfaceView
        android:id="@+id/surface_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <TextView
        android:id="@+id/text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:textColor="#CE3030"
        android:textSize="24sp"
        android:text="no text"/>

</RelativeLayout>

我在清单中请求相机权限，这是视觉库实现：

implementation 'com.google.android.gms:play-services-vision:19.0.0'  

现在，文档没有提到任何关于使用闪光灯的信息，所以我尝试使用相机管理器即兴创作：

android.hardware.camera2.CameraManager

我在onCreate中初始化相机管理器：

mCameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
    mCameraId = mCameraManager.getCameraIdList()[0];
} catch (CameraAccessException e) {
    e.printStackTrace();
}

并在 surfaceCreated 的 cameraView.getHolder（） 回调中打开闪光灯，如下所示

try {
    mCameraManager.setTorchMode(mCameraId, true);
} catch (CameraAccessException e) {
    e.printStackTrace();
}

而且，你猜怎么着，我打开了闪光灯，但现在我无法关闭它。我尝试使用setTorchMode（mCameraId，false），但没有运气。我希望它在打开和关闭之间切换。我猜我有两个连接到相机源的连接（CameraSource 和 CameraManager），所以我能够打开它，但不能关闭它，因为视觉移动 api 正在使用它。

这里有什么解决方法吗？