流式摄像机预览并在ImageView中显示预览为位图

Question

我需要将相机流转换为Bitmap并将其显示为ImageView。以下是CameraPreviewActivity的代码：

public class CameraPreviewActivity extends Activity {

    private MyCamera myCamera;
    private Camera camera;
    private ImageView camView;
    private Runnable r;
    private Bitmap bm;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        myCamera = new MyCamera();
        myCamera.startCamera();
        camView = (ImageView) findViewById(R.id.camViewId);
        setContentView(R.layout.camera_preview_layout);
        getCameraFrameView();
    }

    private void getCameraFrameView() {
        r = new Runnable() {
            @Override
            public void run() {
                bm = myCamera.getCameraFrameBitmap();
                if(bm != null) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            camView.setImageBitmap(bm);
                        }
                    });
                }
            }
        };
        r.run();
    }

}

这是初始化并运行相机预览的类：

public class MyCamera {

    private Camera mCamera = null;
    private SurfaceTexture st = new SurfaceTexture(1);
    private Bitmap cameraFrameBitmap;
    private Camera.Parameters parameters;
    private Camera.Size previewSize;

    public void startCamera() {
        Log.d("MyCamera", "Start Camera Initialized");
        mCamera = Camera.open();
        setupCameraParams();
        try{
            mCamera.setPreviewTexture(st);
            mCamera.startPreview();
            Log.d("MyCamera", "Camera Started Preview");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void setupCameraParams() {
        if(mCamera != null) {
            Log.d("MyCamera", "Setup Camera Params Started");
            parameters = mCamera.getParameters();
            List<Camera.Size> cameraSize = parameters.getSupportedPreviewSizes();
            previewSize = cameraSize.get(0);
            for(Camera.Size s : cameraSize) {
                if((s.width * s.height) > (previewSize.height * previewSize.width)) {
                    previewSize = s;
                }
            }
            parameters.setPreviewSize(previewSize.width, previewSize.height);
            mCamera.setParameters(parameters);
            mCamera.setPreviewCallback(previewCallback);
            Log.d("MyCamera", "Setup Camera Done");
        } else {
            return;
        }
    }

    private Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {
        @Override
        public void onPreviewFrame(byte[] data, Camera camera) {
            if(parameters == null && previewSize == null) {
                return;
            }
            try{
                int format = parameters.getPreviewFormat();
                YuvImage yuvImage = new YuvImage(data, format, previewSize.width, previewSize.height, null);
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                Rect rect = new Rect(0, 0, previewSize.width, previewSize.height);
                yuvImage.compressToJpeg(rect, 100, baos);
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inPurgeable = true;
                options.inInputShareable = true;
                cameraFrameBitmap = BitmapFactory.decodeByteArray(baos.toByteArray(), 0, baos.size(), options);
                baos.flush();
                baos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    };

    public Bitmap getCameraFrameBitmap() {
        return cameraFrameBitmap;
    }

}

这是正确的方法吗？还是有另一种方法将相机预览流式传输到ImageView作为位图？我的应用无法显示相框。我想在运行Runnable时可能会出现问题。我不习惯线程和 Runnable 。