Android | 只要三十分钟就可以在手机上开发一个微笑抓拍神器！！！

今天就用机器学习服务的多人脸识别+表情检测能力写一个微笑抓拍的小demo，做一次实战演练。demo源码github下载请戳这里

华为HMS的kit开发前准备工作都差不多，无非就是添加maven依赖，引入SDK

增量添加如下maven地址：

buildscript {
    repositories {        
        maven {url 'http://developer.huawei.com/repo/'}
    }    }allprojects {
    repositories {       
        maven { url 'http://developer.huawei.com/repo/'}
    }}

把人脸识别的SDK和基础SDK引入

dependencies{ 
  // 引入基础SDK 
  implementation 'com.huawei.hms:ml-computer-vision:1.0.2.300' 
  // 引入人脸检测能力包 
  implementation 'com.huawei.hms:ml-computer-vision-face-recognition-model:1.0.2.300'   
 }

这个主要是用来模型更新的，后面算法有了优化，可以自动下载到手机里面更新

<manifest    
   <application  

检测后拍照：

private MLFaceAnalyzer analyzer;private void createFaceAnalyzer() {
    MLFaceAnalyzerSetting setting =
            new MLFaceAnalyzerSetting.Factory()
                    .setFeatureType(MLFaceAnalyzerSetting.TYPE_FEATURES)
                    .setKeyPointType(MLFaceAnalyzerSetting.TYPE_UNSUPPORT_KEYPOINTS)
                    .setMinFaceProportion(0.1f)
                    .setTracingAllowed(true)
                    .create();                 
    this.analyzer = MLAnalyzerFactory.getInstance().getFaceAnalyzer(setting);
    this.analyzer.setTransactor(new MLAnalyzer.MLTransactor() {
        @Override        public void destroy() {
        }
        @Override        public void transactResult(MLAnalyzer.Result result) {
            SparseArray faceSparseArray = result.getAnalyseList();
            int flag = 0;
            for (int i = 0; i  smilingPossibility) {
                    flag++;
                }
            }
            if (flag > faceSparseArray.size() * smilingRate && safeToTakePicture) {
                safeToTakePicture = false;
                mHandler.sendEmptyMessage(TAKE_PHOTO);
            }
        }
    });}

拍照存储部分：

private void takePhoto() {
    this.mLensEngine.photograph(null,
            new LensEngine.PhotographListener() {
                @Override                public void takenPhotograph(byte[] bytes) {
                    mHandler.sendEmptyMessage(STOP_PREVIEW);
                    Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
                    saveBitmapToDisk(bitmap);
                }
            });}

private void createLensEngine() {
    Context context = this.getApplicationContext();
    // Create LensEngine
    this.mLensEngine = new LensEngine.Creator(context, this.analyzer).setLensType(this.lensType)
            .applyDisplayDimension(640, 480)
            .applyFps(25.0f)
            .enableAutomaticFocus(true)
            .create();}

@Overridepublic void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.setContentView(R.layout.activity_live_face_analyse);
    if (savedInstanceState != null) {
        this.lensType = savedInstanceState.getInt("lensType");
    }
    this.mPreview = this.findViewById(R.id.preview);
    this.createFaceAnalyzer();
    this.findViewById(R.id.facingSwitch).setOnClickListener(this);
    // Checking Camera Permissions
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
        this.createLensEngine();
    } else {
        this.requestCameraPermission();
    }}
    private void requestCameraPermission() {
    final String[] permissions = new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE};
    if (!ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
        ActivityCompat.requestPermissions(this, permissions, LiveFaceAnalyseActivity.CAMERA_PERMISSION_CODE);
        return;
    }}@Overridepublic void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                       @NonNull int[] grantResults) {
    if (requestCode != LiveFaceAnalyseActivity.CAMERA_PERMISSION_CODE) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        return;
    }
    if (grantResults.length != 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        this.createLensEngine();
        return;
    }}