Android6.0以上在代码中获取权限

首先判断sdk的版本

 if (Build.VERSION.SDK_INT >= 23) {
                    int checkCallPhonePermission = ContextCompat.checkSelfPermission(getActivity(),
                            Manifest.permission.CAMERA);
                    if (checkCallPhonePermission != PackageManager.PERMISSION_GRANTED) {
                        ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.CAMERA,}
                                , MY_PERMISSIONS_REQUEST_CALL_PHONE);
                    } else if (ContextCompat.checkSelfPermission(getActivity(),
                            Manifest.permission.WRITE_EXTERNAL_STORAGE)
                            != PackageManager.PERMISSION_GRANTED) {
                        ActivityCompat.requestPermissions(getActivity(),
                                new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.CAMERA},
                                MY_PERMISSIONS_REQUEST_CALL_PHONE2);
                    } else {
                        //有权限，直接扫二维码
                        takeQR();
                    }
                } else {
                    //有权限，直接扫二维码
                    takeQR();
                }

别忘了最后查看是否开启权限成功

 @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        if (requestCode == MY_PERMISSIONS_REQUEST_CALL_PHONE) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
//                //申请成功，可以扫二维码
//                takeQR();
                isCamera=true;
            } else {
                Toast.makeText(activity, "CAMERA PERMISSION DENIED", Toast.LENGTH_SHORT).show();
                isCamera=false;
            }
        }
        if (requestCode == MY_PERMISSIONS_REQUEST_CALL_PHONE2) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
              //申请成功，可以扫二维码
                isStorage=true;
            } else {
                Toast.makeText(activity, "STORAGE PERMISSION DENIED", Toast.LENGTH_SHORT).show();
                isStorage=false;
            }
        }
        if (isCamera||isStorage) {
            //申请成功，可以扫二维码
            return;
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }