Null Pointer Exception when trying to call Drive API even when the reference is initialized

Question

I get the following Null Pointer exception when I try to save an image in Google Drive:

Attempt to invoke virtual method 'com.google.api.services.drive.Drive$Files com.google.api.services.drive.Drive.files()' on a null object reference
                          java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.api.services.drive.Drive$Files com.google.api.services.drive.Drive.files()' on a null object reference
                              at com.amrutpatil.makeanote.GDActions.search(GDActions.java:208)
                              at com.amrutpatil.makeanote.NotesActivity$2.run(NotesActivity.java:154)

GDActions.java:

I first intialize the GoogleApiClient in the init method and then try to get the files in the search method.

static void init(NotesActivity ctx, String email) {
        if (ctx != null && email != null) {
            mGAC = new GoogleApiClient.Builder(ctx).addApi(Drive.API)
                    .addScope(Drive.SCOPE_FILE).setAccountName(email)
                    .addConnectionCallbacks(ctx).addOnConnectionFailedListener(ctx).build();

            mGOOSvc = new com.google.api.services.drive.Drive.Builder(
                    AndroidHttp.newCompatibleTransport(), new GsonFactory(), GoogleAccountCredential
                    .usingOAuth2(ctx, Arrays.asList(DriveScopes.DRIVE_FILE))
                    .setSelectedAccountName(email)
            ).build();
        }
    }

static ArrayList<GF> search(String prId, String titl, String mime) {
            ArrayList<GF> gfs = new ArrayList<>();
            String qryClause = "'me' in owners and ";
            if (prId != null) qryClause += "'" + prId + "' in parents and ";
            if (titl != null) qryClause += "title = '" + titl + "' and ";
            if (mime != null) qryClause += "mimeType = '" + mime + "' and ";
            qryClause = qryClause.substring(0, qryClause.length() - " and ".length());
            com.google.api.services.drive.Drive.Files.List qry = null;
            try {
                qry = mGOOSvc.files().list().setQ(qryClause)
                        .setFields("items(id, labels/trashed, title), nextPageToken");   //Error here
                gfs = search(gfs, qry);
            } catch (GoogleAuthIOException gaiEx) {
                try {
                    gfs = search(gfs, qry);
                    gaiEx.printStackTrace();
                } catch (Exception g) {
                    GDUT.le(g);
                }
            } catch (Exception e) {
                GDUT.le(e);
            }
            return gfs;
        }

NotesActivity.java

@Override
    public void onLoadFinished(Loader<List<Note>> loader, List<Note> data) {
        this.mNotes = data;

        Thread[] threads = new Thread[mNotes.size()];
        int threadCounter = 0;

        for(final Note aNote : mNotes){

            if(AppConstant.GOOGLE_DRIVE_SELECTION == aNote.getStorageSelection()){
                GDUT.init(this);

                if(checkPlayServices() && checkUserAccount()){
                    GDActions.init(this, GDUT.AM.getActiveEmil());
                    GDActions.connect(true);
                }

                threads[threadCounter] = new Thread(new Runnable() {
                    @Override
                    public void run() {
                        do{
                            //Get the image file
                            ArrayList<GDActions.GF> gfs = GDActions.search(AppSharedPreferences.getGoogleDriveResourceId(getApplicationContext()),
                                    aNote.getImagePath(), GDUT.MIME_JPEG);   //Error here

                            if(gfs.size() > 0){
                                //Retrieve the file, convert it into Bitmap to display on the screen
                                byte[] imageBytes = GDActions.read(gfs.get(0).id, 0);


                                Bitmap bitmap = BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
                                aNote.setBitmap(bitmap);
                                mIsImageNotFound = false;
                                mNotesAdapter.setData(mNotes);
                                runOnUiThread(new Runnable() {
                                    @Override
                                    public void run() {

                                        mNotesAdapter.notifyImageObtained();
                                    }
                                });
                            } else{
                                aNote.setBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.ic_loading));
                                mIsImageNotFound = true;
                                try{
                                    Thread.sleep(500);
                                } catch (InterruptedException e){
                                    e.printStackTrace();
                                }
                            }
                        }while(mIsImageNotFound);
                    }
                });
                threads[threadCounter].start();
                threadCounter++;
            } else {
                aNote.setHasNoImage(true);
            }
        }
        mNotesAdapter.setData(mNotes);  
        changeNoItemTag();
    }

Possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — RaminS, Mar 27 '16 at 21:05
Have you tested that GDUT.AM.getActiveEmil() doesn't return null? — RubioRic, Mar 27 '16 at 21:11
Yes, I did test that getActiveEmil method does not return a null. Currently, it does return a valid email. — ap6491, Mar 27 '16 at 21:30

score 0 · Answer 1 · answered Mar 28 '16 at 23:50

Turns out that there was a permissions issue. Although I had GET_ACCOUNTS permission set in my AndroidManifest.xml file, I needed to manually enable Contacts permissions in my app settings.

It may be a device specific issue as I was running my app on a Nexus 6 physical device with Android Marshmallow 6.0.1.

You might want to check you app settings just to be safe.

Null Pointer Exception when trying to call Drive API even when the reference is initialized

1 Answers1