I am trying to take a picture from the camera app and save it into the app's files , searching until now lead me to something about content Uris.. (I have no idea on what they are or how to use them). I am already able to save a photo in the external memory so if there is a way to move photos from there into the apk file it would be nice.
the path I wanted to put the photos in is "appname/app/src/main/assets/photos"
this is the code I have now:
public class Add_Comment_Picture extends AppCompatActivity {
    static final int CAM_REQUEST = 1;
    ImageView imageView;
    ImageButton button;
    private static final int REQUEST_CODE = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add__comment__picture);
    //    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CODE);
        button = (ImageButton) findViewById(R.id.imageButtonCamera);
        imageView = (ImageView) findViewById(R.id.imageView);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Intent camera_intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                File file = getFile();
                camera_intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
                startActivityForResult(camera_intent , CAM_REQUEST);
            }
        });
    }
    @Override
    protected void onStart() {
        super.onStart();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            int hasWritePermission = checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE);
            int hasReadPermission = checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE);
            int hasCameraPermission = checkSelfPermission(Manifest.permission.CAMERA);
            List<String> permissions = new ArrayList<String>();
            if (hasWritePermission != PackageManager.PERMISSION_GRANTED) {
                permissions.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
            }
            if (hasReadPermission != PackageManager.PERMISSION_GRANTED) {
                permissions.add(Manifest.permission.READ_EXTERNAL_STORAGE);
            }
            if (hasCameraPermission != PackageManager.PERMISSION_GRANTED) {
                permissions.add(Manifest.permission.CAMERA);
            }
            if (!permissions.isEmpty()) {
                requestPermissions(permissions.toArray(new String[permissions.size()]), 111);
            }
        }
    }
    private File getFile()
    {
        File folder = new File("sdcard/camera_app");
        if (!folder.exists())
        {
            folder.mkdir();
        }
        File image_file = new File(folder,"cam_image.jpg");
        return image_file;
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        String path = "sdcard/camera_app/cam_image.jpg";
        imageView.setImageDrawable(Drawable.createFromPath(path));
        super.onActivityResult(requestCode, resultCode, data);
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        switch (requestCode) {
            case 111: {
                for (int i = 0; i < permissions.length; i++) {
                    if (grantResults[i] == PackageManager.PERMISSION_GRANTED) {
                        System.out.println("Permissions --> " + "Permission Granted: " + permissions[i]);
                    } else if (grantResults[i] == PackageManager.PERMISSION_DENIED) {
                        System.out.println("Permissions --> " + "Permission Denied: " + permissions[i]);
                    }
                }
            }
            break;
            default: {
                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
            }
        }
    }
}