---

if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE}, 100);
}

surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.addCallback(new SurfaceHolder.Callback() {
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            camera = Camera.open();
            camera.setPreviewDisplay(holder);
            camera.startPreview();
            isPreviewRunning = true;
        } catch (Exception e) {}
    }
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {}
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        if (camera != null) {
            camera.stopPreview();
            camera.release();
            camera = null;
            isPreviewRunning = false;
        }
    }
});