Camera2 API获取vendor.camera.aux.packagelist权限被拒问题咨询

API 探路者

2026-8-6

问题描述

我用下述代码通过外部USB摄像头（网络摄像头）捕获图像，代码在多数设备上运行正常，但在Android 9.0（API Level 28）设备上，尝试获取Camera ID打开摄像头时，Logcat会抛出**Access denied finding property "vendor.camera.aux.packagelist"**错误。已授予相机、外部存储及USB设备权限，请求解释该问题原因。

代码实现

package com.example.camerastatuscheck;

import static android.content.ContentValues.TAG;

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

import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbManager;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraManager;
import android.os.Bundle;
import android.os.PendingIntent;
import android.util.Log;
import android.widget.Button;
import android.widget.TextureView;
import android.widget.Toast;

import java.util.HashMap;
import java.util.Iterator;

public class MainActivity extends AppCompatActivity {
    private static final int REQUEST_CAMERA_PERMISSION = 200;
    public static final String ACTION_USB_PERMISSION = "com.example.usbtestapp.USB_PERMISSION";
    static final int intentFlags = android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.S ? PendingIntent.FLAG_MUTABLE : 0;
    static final int MY_CAMERA_PERMISSION_CODE = 100;
    private Context ContextofMainAcitivity;
    public IntentFilter USBconnectdisconnect_intentFilter;
    public Intent GetEXTRA_PERMISSION_GRANTEDIntent;
    public PendingIntent current_usbpermissionIntent;
    public UsbDevice current_usbdevice;
    public UsbManager current_usbManager;
    private static final String TAG = "usbtestapp";
    TextureView new_textureview;
    Button new_open_camera,nextactivity;
    UsbDeviceConnection usbConnection;
    PendingIntent permissionIntent;

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

    private void camera_start() {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED ) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
            return;
        }
        Log.d("camera start", "success");
        UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);

        HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
        Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
        while(deviceIterator.hasNext()){
            UsbDevice device = deviceIterator.next();
            manager.requestPermission(device, permissionIntent);
            //your code
        }
        Log.d("Camrea srtart","camera start");
        CameraManager cameraManager = (CameraManager)getSystemService(CAMERA_SERVICE);
        try {
            for (String cameraId : cameraManager.getCameraIdList()) {
                CameraCharacteristics chars = cameraManager.getCameraCharacteristics(cameraId);
                int deviceLevel = chars.get(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL);
                Log.d(TAG, " **** device ["+cameraId+"] level:"+deviceLevel);
                Toast.makeText(getApplicationContext(), "cameraId", Toast.LENGTH_SHORT).show();
            }
        } catch(CameraAccessException e){
            e.printStackTrace();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_CAMERA_PERMISSION) {
            if (grantResults[0] == PackageManager.PERMISSION_DENIED) {
                Toast.makeText(MainActivity.this, "Sorry!!!, you can't use this app without granting permission", Toast.LENGTH_LONG).show();
                finish();
            }
        }
    }

    private final BroadcastReceiver usbReceiver = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (ACTION_USB_PERMISSION.equals(action)) {
                synchronized (this) {
                    UsbDevice device = (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                    if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                        if(device != null){
                            Toast.makeText(context, "Permission granded", Toast.LENGTH_SHORT).show();
                        }
                    } else {
                        Toast.makeText(context, "Permission denied", Toast.LENGTH_SHORT).show();
                    }
                }
            }
        }
    };

    public boolean supportsExternalCameras() {
        return this.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_EXTERNAL);
    }
}

（注：修复了原代码中fornewpos.this的错误引用，补充了缺失的import类）

日志信息

2023-01-07 15:31:55.318 23651-23651 libc com.example.cmaera5 E Access denied finding property "vendor.camera.aux.packagelist"

AndroidManifest配置

<uses-feature
        android:name="android.hardware.camera"
        android:required="true" />

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-feature android:name="android.hardware.camera2.full" />
    <uses-feature android:name="android.hardware.camera.autofocus" />
    <uses-feature android:name="android.hardware.usb.host" />
    <uses-feature android:name="android.hardware.usb.accessory" />
    <uses-feature android:name="android.hardware.usb" />

    <uses-permission android:name="android.permission.RECORD_AUDIO" />

问题原因分析

系统属性权限限制：vendor.camera.aux.packagelist是厂商自定义的系统属性，用于管控可访问辅助摄像头（如USB外接摄像头）的应用列表。Android 9.0中，普通应用没有读取这类厂商系统属性的权限，该错误是系统层面的权限拦截导致，和你手动申请的应用级权限无关。
厂商Camera2 API实现差异：部分Android 9.0设备的厂商在实现Camera2 API时，会尝试读取该属性来判断应用是否有权访问外接USB摄像头，但由于普通应用无读取权限，便抛出该错误日志。
代码潜在问题：原代码中permissionIntent变量未初始化就调用manager.requestPermission(device, permissionIntent)，会导致USB权限请求失效，可能间接影响USB摄像头的识别流程。

解决建议

忽略日志错误：该错误属于系统层面的权限限制，多数情况下不会影响USB摄像头的正常使用，只要应用能正常获取Camera ID并打开摄像头，可直接忽略这条日志。
初始化USB权限请求的PendingIntent：在onCreate方法中补充初始化逻辑，确保USB权限请求正常执行：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    // 初始化USB权限请求的PendingIntent
    permissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), intentFlags);
    // 注册USB广播接收器
    USBconnectdisconnect_intentFilter = new IntentFilter(ACTION_USB_PERMISSION);
    registerReceiver(usbReceiver, USBconnectdisconnect_intentFilter);
    camera_start();
}

适配Android 9.0 USB摄像头：部分厂商的Android 9.0设备对外接USB摄像头支持有限，可尝试使用第三方USB摄像头库替代原生Camera2 API，绕过系统属性限制。
清理冗余代码：移除原代码中重复定义的REQUEST_CAMERA_PERMISSION常量，保证代码逻辑清晰。

内容的提问来源于stack exchange，提问作者Ac. Selvan