Как настроить обновление поверхности на Android?

Question

Я в настоящее время реализую пользовательскую функцию камеры, используя Surfaceview. Теперь я хочу реализовать следующее: когда я перехожу на другой экран и возвращаюсь, я хочу запустить его снова, но это не работает. Так что я использую Finish () onPause, но я хочу найти лучший способ. Ошибки, которые я сделал, заключаются в следующем. Буду очень признателен, если вы подскажете, как это решить.

**MainActivity.java**


    public class MainActivity extends AppCompatActivity {

    Button cameraButton;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


    }

    @Override
    protected void onResume() {
        super.onResume();

        final CameraPreview surfaceView = (CameraPreview) findViewById(R.id.main);
        surfaceView.setBackground(ContextCompat.getDrawable(this, R.drawable.human_icon_21));
        SurfaceHolder holder;
        holder = surfaceView.getHolder();
        holder.addCallback(surfaceView);
        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);


        cameraButton = (Button) findViewById(R.id.button);
        cameraButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                surfaceView.takePhoto(new Camera.PictureCallback() {
                    @Override
                    public void onPictureTaken(byte[] data, Camera camera) {


                      FileOutputStream outStream = null;
                        try {

                            String str = String.format(Environment.getExternalStorageDirectory()+"/Pictures/DICM/android_hong_test.jpg",
                                    System.currentTimeMillis());
                            outStream = new FileOutputStream(str);

                            outStream.write(data);
                            outStream.close();

                            Intent intent = new Intent(MainActivity.this,
                            ResultActivity.class);
                            intent.putExtra("strParamName", str);

                            startActivity(intent);


                        }

                        catch (FileNotFoundException e) {
                            e.printStackTrace();
                        }

                        catch (IOException e) {
                            e.printStackTrace();
                        }

                        finally {
                        }

                        Toast.makeText(getApplicationContext(),
                                "Picture Saved", Toast.LENGTH_LONG).show();

                    }
                });
            }
        });
    }

    @Override
    protected void onPause() {
      super.onPause();

      //finish();
    }
}





**cameraview.java**

    public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {

    String TAG = "WOW";

    public List<Camera.Size> prSupportedPreviewSizes;
    private Camera.Size prPreviewSize;
    public  Camera mCamera;

    public CameraPreview(Context context) {
        super(context);

    }

    public CameraPreview(Context context, AttributeSet attrs) {
        super(context, attrs);


        mCamera = Camera.open();
        prSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
    }

    public boolean takePhoto(Camera.PictureCallback handler){
        if(mCamera != null){
            mCamera.takePicture(null,null,handler);
            return true;
        }else{
            return false;
        }
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {




        try {


            Camera.Parameters parameters = mCamera.getParameters();

            if (getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE) {
                parameters.set("orientation", "portrait");
                mCamera.setDisplayOrientation(90);
                parameters.setRotation(90);
            } else {
                parameters.set("orientation", "landscape");
                mCamera.setDisplayOrientation(0);
                parameters.setRotation(0);
            }
            mCamera.setParameters(parameters);

            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            Log.d(TAG, "Error setting camera preview: " + e.getMessage());
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        Log.v("jyp@@@","surfaceDestroyed ");
       if (mCamera != null) {
            mCamera.stopPreview();
            mCamera.release();
            mCamera = null;
        }
    }


    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {




        if (holder.getSurface() == null){


            return;
        }

        // 우선 멈춘다
        try {
            mCamera.stopPreview();
        } catch (Exception e){
            // 프리뷰가 존재조차 하지 않는 경우다


        }


        Camera.Parameters parameters = mCamera.getParameters();
        List<String> focusModes = parameters.getSupportedFocusModes();
        if (focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {
            parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
        }
//
//        Camera.Size size = getBestPreviewSize(w, h);
        Log.v("jyp@@@","surfaceChanged  width: "+prPreviewSize.width);
        Log.v("jyp@@@","surfaceChanged  height: "+prPreviewSize.height);

        parameters.setPreviewSize(prPreviewSize.width, prPreviewSize.height);
        mCamera.setParameters(parameters);

        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();

        } catch (Exception e){
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.v("jyp@@@","onMeasure()");

        final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
        Log.v("jyp@@@","width: "+width);
        Log.v("jyp@@@","height: "+height);
        setMeasuredDimension(width, height);

        if (prSupportedPreviewSizes != null) {
            prPreviewSize = getOptimalPreviewSize(prSupportedPreviewSizes, width, height);
            Log.v("jyp@@@","prPreviewSize.width: "+prPreviewSize.width);
            Log.v("jyp@@@","prPreviewSize.height: "+prPreviewSize.height);
        }
    }

    public Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {

        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) h / w;

        if (sizes == null)
            return null;

        Camera.Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        for (Camera.Size size : sizes) {
            double ratio = (double) size.width / size.height;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                continue;

            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Camera.Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }

        return optimalSize;
    }



}