[18일차]퍼미션

shouldShowRequestPermissionRatonale 왜 이 퍼미션을 획득해야하는지 설명해야하는거

프로텍션 레벨 Dangerous Permission 은 개인정보와 관련된 Permission 

Compat checkSelfPermission 이 퍼미션을 가지고 있는지 아닌지 획득을 해준다.ㅏ 

shouldShowReqeustPermissionRationale 사용자에게 구체적으로 퍼미션 화면을 보여줌

setResult 해가지고 onRequestPermissionResult 로 결과가 넘어온다. 

private void checkPermission() {
    List<String> permissions = new ArrayList<>();
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        permissions.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
    }

    if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        permissions.add(Manifest.permission.READ_EXTERNAL_STORAGE);
    }

    if (permissions.size() > 0) {
        boolean isShowUI = false;
        for (String perm : permissions) {
            if (ActivityCompat.shouldShowRequestPermissionRationale(this, perm)) {
                isShowUI = true;
                break;
            }
        }

        final String[] perms = permissions.toArray(new String[permissions.size()]);

        if (isShowUI) {
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Permission");
            builder.setMessage("External Storage...");
            builder.setCancelable(false);
            builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {
                    ActivityCompat.requestPermissions(ExternalActivity.this, perms, RC_PERMISSION);
                }
            });
            builder.create().show();
            return;
        }

        ActivityCompat.requestPermissions(this, perms, RC_PERMISSION);
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == RC_PERMISSION) {
        if (permissions != null) {
            boolean granted = true;
            for (int i = 0; i < permissions.length; i++) {
                if (grantResults[i] != PackageManager.PERMISSION_GRANTED) {
                    granted = false;
                }
            }
            if (!granted) {
                Toast.makeText(this, "permission not granted", Toast.LENGTH_SHORT).show();
                finish();
            }
        }
    }
}