Android相机调用-CameraX【外接摄像头】【USB摄像头】

2023-10-22 06:33

短信预约 -IT技能 免费直播动态提醒

Android相机调用有原生的Camera和Camera2，我觉得调用代码都太复杂了，CameraX调用代码简洁很多。

说明文档：https://developer.android.com/jetpack/androidx/releases/camera?hl=zh-cn

现有查到的调用资料都不够新，对于外接摄像头（USB摄像头）这类非前置也非后置摄像头的设备调用，都说是没有实现。旧版本的库可能更多目标用户是基于手机的，1.3.0-alpha03版本针对外接摄像头有增加配置项（CameraSelector.LENS_FACING_EXTERNAL），使用该配置项可以实现外接摄像头的调用。

0，摄像头选择可用值

        public static final int LENS_FACING_UNKNOWN = -1;        public static final int LENS_FACING_FRONT = 0;        public static final int LENS_FACING_BACK = 1;        @ExperimentalLensFacing    public static final int LENS_FACING_EXTERNAL = 2;

1，在AndroidManifest.xml添加权限

2，在settings.gradle或build.gradle添加maven

    repositories {        google()        mavenCentral()        maven { url 'https://jitpack.io' }    }

3，在build.gradle添加依赖库

    //摄像头预览库    implementation "androidx.camera:camera-core:1.3.0-alpha04"    // CameraX Camera2 extensions[可选]拓展库可实现人像、HDR、夜间和美颜、滤镜但依赖于OEM    implementation "androidx.camera:camera-camera2:1.3.0-alpha04"    // CameraX Lifecycle library[可选]避免手动在生命周期释放和销毁数据    implementation "androidx.camera:camera-lifecycle:1.3.0-alpha04"    // CameraX View class[可选]最佳实践，最好用里面的PreviewView，它会自行判断用SurfaceView还是TextureView来实现    implementation 'androidx.camera:camera-view:1.3.0-alpha04'

4，开启预览代码

    private ListenableFuture cameraProviderFuture;    private PreviewView previewView;    private ProcessCameraProvider cameraProvider;    ImageView picture = null;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        picture = (ImageView) findViewById(R.id.picture);        previewView=findViewById(R.id.previewView);//初始化                //高版本系统动态权限申请        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_DENIED) {            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {                requestPermissions(new String[]{                        Manifest.permission.CAMERA,                }, 11);            }        } else {            //启动相机            startCamera();        }        takePhoto.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                takePhoto(picture);//取图识别            }        });    }    @Override    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {        super.onRequestPermissionsResult(requestCode, permissions, grantResults);        if (requestCode==11){//获取权限后，开启摄像头            //启动相机            startCamera();        }    }    private void startCamera() {        // 请求 CameraProvider        cameraProviderFuture = ProcessCameraProvider.getInstance(this);        //检查 CameraProvider 可用性，验证它能否在视图创建后成功初始化        cameraProviderFuture.addListener(() -> {            try {                ProcessCameraProvider cameraProvider = cameraProviderFuture.get();                bindPreview(cameraProvider);            } catch (ExecutionException | InterruptedException e) {                // No errors need to be handled for this Future.                // This should never be reached.            }        }, ContextCompat.getMainExecutor(this));    }    //选择相机并绑定生命周期和用例    private void bindPreview(@NonNull ProcessCameraProvider cp) {        this.cameraProvider=cp;        Preview preview = new Preview.Builder()                .build();        @SuppressLint("UnsafeOptInUsageError")        CameraSelector cameraSelector = new CameraSelector.Builder()                .requireLensFacing(CameraSelector.LENS_FACING_BACK)//CameraSelector.LENS_FACING_EXTERNAL                .build();        preview.setSurfaceProvider(previewView.getSurfaceProvider());        cameraProvider.unbindAll();//解绑组件        cameraProvider.bindToLifecycle((LifecycleOwner) this, cameraSelector, preview);    }    //拍照，这里偷懒了，直接取了预览控件的图片，需要拍照的再去看看官方文档吧    public void takePhoto(View view)    {        Log.e("OCR", "takePhoto");        Bitmap bitmap = previewView.getBitmap();        view.setBackground(new BitmapDrawable(getApplicationContext().getResources(),bitmap)); //show picture    }    @Override    protected void onDestroy() {        super.onDestroy();        cameraProvider.unbindAll();    }

5，界面布局

6，测试效果（文字识别部分请忽略）

7，库的调用版本是比较新的，建议JDK版本不要太低，我使用的是16.0.2