Java Code Examples for android.os.AsyncTask

private void fetchChannels() {
    if (Lbry.ownChannels != null && Lbry.ownChannels.size() > 0) {
        updateChannelList(Lbry.ownChannels);
        return;
    }

    fetchingChannels = true;
    disableChannelSpinner();
    ClaimListTask task = new ClaimListTask(Claim.TYPE_CHANNEL, progressLoadingChannels, new ClaimListResultHandler() {
        @Override
        public void onSuccess(List<Claim> claims) {
            Lbry.ownChannels = new ArrayList<>(claims);
            updateChannelList(Lbry.ownChannels);
            enableChannelSpinner();
            fetchingChannels = false;
        }

        @Override
        public void onError(Exception error) {
            enableChannelSpinner();
            fetchingChannels = false;
        }
    });
    task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
}
 

/**
 * Execute in background the HTTP calls to add and remove members.
 */
public void asyncUpdateGroup(final String senderId, final String apiKey,
                             final String groupName, final String groupKey,
                             Bundle newMembers, Bundle removedMembers) {
    final Bundle members2Add = new Bundle(newMembers);
    final Bundle members2Remove = new Bundle(removedMembers);
    new AsyncTask<Void, Void, Void>(){
        @Override
        protected Void doInBackground(Void... voids) {
            if (members2Add.size() > 0) {
                addMembers(senderId, apiKey, groupName, groupKey, members2Add);
            }
            if (members2Remove.size() > 0) {
                removeMembers(senderId, apiKey, groupName, groupKey, members2Remove);
            }
            return null;
        }
    }.execute();
}
 

@Override
public void onReceive(Context context, Intent intent) {
    Log.i(TAG, "com.suyashsrijan.forcedoze.REMOVE_WHITELIST broadcast intent received");
    final String packageName = intent.getStringExtra("packageName");
    Log.i(TAG, "Package name received: " + packageName);
    if (packageName != null) {
        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                List<String> output = Shell.SH.run("dumpsys deviceidle whitelist -" + packageName);
                if (output != null) {
                    for (String s : output) {
                        Log.i(TAG, s);
                    }
                } else {
                    Log.i(TAG, "Error occurred while executing command (" + "dumpsys deviceidle whitelist -packagename" + ")");
                }
            }
        });
    } else {
        Log.i(TAG, "Package name null or empty");
    }
}
 

private void goToSecondSceneWithDelay() {
    new AsyncTask<Void, Void, Void>() {
        @Override
        protected Void doInBackground(Void... params) {
            try {
                Log.d(TAG, "Do In Background");
                Thread.sleep(3000);
            } catch(InterruptedException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            Log.d(TAG, "OnPostExecute");
            super.onPostExecute(aVoid);
            Flow.get(SceneMainView.this).set(SceneMainSecondKey.create());
        }
    }.execute();
}
 

/**
 * Retrieves contacts matching an email address.
 * Uses raw URI when <code>rawUri</code> is <code>true</code>, makes assets copy otherwise.
 *
 * @param emailAddress email address to match
 * @param callback user provided callback to run at completion
 */
@ReactMethod
public void getContactsByEmailAddress(final String emailAddress, final Callback callback) {
    AsyncTask<Void,Void,Void> myAsyncTask = new AsyncTask<Void,Void,Void>() {
        @Override
        protected Void doInBackground(final Void ... params) {
            Context context = getReactApplicationContext();
            ContentResolver cr = context.getContentResolver();
            ContactsProvider contactsProvider = new ContactsProvider(cr);
            WritableArray contacts = contactsProvider.getContactsByEmailAddress(emailAddress);

            callback.invoke(null, contacts);
            return null;
        }
    };
    myAsyncTask.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR);
}
 

@SuppressLint("StaticFieldLeak")
private void loadTexturesAsync(final Context context) {
	if (context == null) {
		return;
	}

	new AsyncTask<Void, Void, Cursor>() {
		@Override
		protected Cursor doInBackground(Void... nothings) {
			return loadTextures();
		}

		@Override
		protected void onPostExecute(Cursor cursor) {
			if (!isAdded() || cursor == null) {
				return;
			}

			updateAdapter(context, cursor);
		}
	}.execute();
}
 

/**
 * Generates the authentication encryption key in a background thread (if necessary).
 */
private static void triggerMacKeyGeneration() {
    synchronized (sLock) {
        if (sKey != null || sMacKeyGenerator != null) {
            return;
        }

        sMacKeyGenerator = new FutureTask<SecretKey>(new Callable<SecretKey>() {
            // SecureRandomInitializer addresses the bug in SecureRandom that "TrulyRandom"
            // warns about, so this lint warning can safely be suppressed.
            @SuppressLint("TrulyRandom")
            @Override
            public SecretKey call() throws Exception {
                KeyGenerator generator = KeyGenerator.getInstance(MAC_ALGORITHM_NAME);
                SecureRandom random = new SecureRandom();
                SecureRandomInitializer.initialize(random);
                generator.init(MAC_KEY_BYTE_COUNT * 8, random);
                return generator.generateKey();
            }
        });
        AsyncTask.THREAD_POOL_EXECUTOR.execute(sMacKeyGenerator);
    }
}
 

@Override
public void handleButtonPress(int index) {
  if (index == 0) {
    WifiParsedResult wifiResult = (WifiParsedResult) getResult();
    WifiManager wifiManager = (WifiManager) getActivity().getSystemService(Context.WIFI_SERVICE);
    if (wifiManager == null) {
      Log.w(TAG, "No WifiManager available from device");
      return;
    }
    final Activity activity = getActivity();
    activity.runOnUiThread(new Runnable() {
      @Override
      public void run() {
        Toast.makeText(activity.getApplicationContext(), R.string.wifi_changing_network, Toast.LENGTH_SHORT).show();
      }
    });
    new WifiConfigManager(wifiManager).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, wifiResult);
    parent.restartPreviewAfterDelay(0L);
  }
}
 

/**
 * This method unregister from the GCM services and also pusher
 * server in the background mode. 
 * 
 * @param context
 */
public static void unregisterInBackground(final Context context) {
	
	new AsyncTask<Void, Void, String>() {

		@Override
		protected String doInBackground(Void... params) {

			try {
				GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(context);
				gcm.unregister();
				
				// Unregister the GCM info from pusher server.
				String regId = Preferences.getPreference(context, Preferences.CURRENT_GCM_ID);
				GCMIntentService.removeFromPusher(context, regId);
			} catch (IOException e) {
				Logger.error(TAG, "GCM Un-registration failed.", e);
			} 
			
			return null;
		}
	}.execute();
}
 

public static void saveChanges(final ExifInterface exifInterface,
                               final List<ExifItem> editedItems, final Callback callback) {
    if (exifInterface == null) {
        return;
    }
    AsyncTask.execute(new Runnable() {
        @Override
        public void run() {
            boolean success = true;
            for (ExifItem item : editedItems) {
                exifInterface.setAttribute(item.getTag(), item.getValue());
            }
            try {
                exifInterface.saveAttributes();
            } catch (IOException e) {
                e.printStackTrace();
                success = false;
            }

            if (callback != null) {
                callback.done(success);
            }
        }
    });
}
 

/**
 * Retrieves <code>thumbnailPath</code> for contact, or <code>null</code> if not available.
 *
 * @param contactId contact identifier, <code>recordID</code>
 * @param callback callback
 */
@ReactMethod
public void getPhotoForId(final String contactId, final Callback callback) {
    AsyncTask<Void,Void,Void> myAsyncTask = new AsyncTask<Void,Void,Void>() {
        @Override
        protected Void doInBackground(final Void ... params) {
            Context context = getReactApplicationContext();
            ContentResolver cr = context.getContentResolver();
            ContactsProvider contactsProvider = new ContactsProvider(cr);
            String photoUri = contactsProvider.getPhotoUriFromContactId(contactId);

            callback.invoke(null, photoUri);
            return null;
        }
    };
    myAsyncTask.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR);
}
 

public <T> CancelableBackgroundOperation executeApiAsync(Intent data, OpenPgpDataSource dataSource,
        OpenPgpDataSink<T> dataSink, final IOpenPgpSinkResultCallback<T> callback) {
    Messenger messenger = new Messenger(new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(Message message) {
            callback.onProgress(message.arg1, message.arg2);
            return true;
        }
    }));
    data.putExtra(EXTRA_PROGRESS_MESSENGER, messenger);

    OpenPgpSourceSinkAsyncTask<T> task = new OpenPgpSourceSinkAsyncTask<>(data, dataSource, dataSink, callback);

    // don't serialize async tasks!
    // http://commonsware.com/blog/2012/04/20/asynctask-threading-regression-confirmed.html
    task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, (Void[]) null);

    return task;
}
 

protected void setGroupViewThumb(FileUtil.MediaFileType type, String thumb, ImageView icon, TextView text, RequestOptions options) {
    if (type == FileUtil.MediaFileType.MOVIE ||
            type == FileUtil.MediaFileType.IMG) {
        if (options == null) {
            Glide.with(mContext).load(thumb).listener(mRequestListener).into(icon);
        } else {
            Glide.with(mContext).load(thumb).listener(mRequestListener).apply(options).into(icon);
        }
    } else if (type == FileUtil.MediaFileType.APP) {
        Bitmap b = sLruCache.get(thumb);
        if (b == null) {
            AppThumbTask task = new AppThumbTask(sLruCache, mContext, icon);
            task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, new File(thumb));
        } else
            icon.setImageBitmap(b);
    } else if (type == FileUtil.MediaFileType.MP3) {
        text.setText(R.string.music);
    } else if (type == FileUtil.MediaFileType.DOC) {
        text.setText(R.string.doc);
    } else if (type == FileUtil.MediaFileType.RAR) {
        text.setText(R.string.rar);
    }
}
 

private void load(Uri uri, OnLoadCompleteListener onLoadCompleteListener, int[] userPages) {

        if (!recycled) {
            throw new IllegalStateException("Don't call load on a PDF View without recycling it first.");
        }

        // Manage UserPages if not null
        if (userPages != null) {
            this.originalUserPages = userPages;
            this.filteredUserPages = ArrayUtils.deleteDuplicatedPages(originalUserPages);
            this.filteredUserPageIndexes = ArrayUtils.calculateIndexesInDuplicateArray(originalUserPages);
        }

        this.onLoadCompleteListener = onLoadCompleteListener;

        // Start decoding document
        decodingAsyncTask = new DecodingAsyncTask(uri, this);
        decodingAsyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);

        renderingAsyncTask = new RenderingAsyncTask(this);
        renderingAsyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    }
 

private void checkNuxSettings() {
    if (nuxMode == ToolTipMode.DISPLAY_ALWAYS) {
        String nuxString = getResources().getString(R.string.com_facebook_tooltip_default);
        displayNux(nuxString);
    } else {
        // kick off an async request
        final String appId = Utility.getMetadataApplicationId(getContext());
        AsyncTask<Void, Void, FetchedAppSettings> task = new AsyncTask<Void, Void, Utility.FetchedAppSettings>() {
            @Override
            protected FetchedAppSettings doInBackground(Void... params) {
                FetchedAppSettings settings = Utility.queryAppSettings(appId, false);
                return settings;
            }

            @Override
            protected void onPostExecute(FetchedAppSettings result) {
                showNuxPerSettings(result);
            }
        };
        task.execute((Void[])null);
    }

}
 

public void getStargazers(final Repository repository, final GetStargazersCallback callback) {
    new AsyncTask<Void, Void, List<Star>>() {
        @Override
        protected List<Star> doInBackground(Void... params) {
            return getStargazersSync(repository);
        }

        @Override
        protected void onPostExecute(List<Star> starList) {
            if (starList != null) {
                callback.onStargazersLoaded(starList);
            } else {
                callback.onDataNotAvailable();
            }
        }
    }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
}
 

/**
 * Action after download finished of not
 *
 * @param result flag download success or not
 */
@Override
protected void onPostExecute(Boolean result) {

    //notify download complete
    if (context != null)
        Toast.makeText(context, result == true ?
                        context.getString(R.string.download_complete) :
                        context.getString(R.string.download_failed)
                , Toast.LENGTH_LONG).show();

    //pass the download statue to notification
    if (notificationDownloaderFlag) {
        notificationManager.cancel(0);
        if (result) {
            showCompleteNotification();
            AppPreference.DownloadStatues(AppConstants.Preferences.DOWNLOAD_SUCCESS);
        } else {
            showFailedNotification();
            AppPreference.DownloadStatues(AppConstants.Preferences.DOWNLOAD_FAILED);
        }
    }

    //run extraction service if zip file or stop service
    if (fileExtension.toLowerCase().equals("zip") && result) {
        new UnZipping(context).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, filePath, fileName);
    } else {
        //send broadcast of success or failed
        LocalBroadcastManager.getInstance(context).sendBroadcast(new Intent(AppConstants.Download.INTENT)
                .putExtra(AppConstants.Download.DOWNLOAD, result == true ?
                        AppConstants.Download.SUCCESS :
                        AppConstants.Download.FAILED));
        if (context instanceof Service)
            ((Service) context).stopService(new Intent(context, DownloadService.class));
    }

}
 

protected void markNotificationAsReadOnShow(int position, Notification notification) {
  try {
    new MarkNotificationAsReadTask().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, notification.getId());
    ActivityTracker.sendEvent(MainActivity.this, ActivityTracker.CAT_UI, "notification_mark_read_on_show", "", 0L);
    notificationsListAdapter.removeNotificationByPosition(position);
    notifyDataSetChanged();
  } catch (RejectedExecutionException e) {
    //nothing to do
  }
}
 

private void asyncLoad(String tag, ImageView imageView, AsyncTask<String, Integer, Bitmap> task) {
    Set<ImageView> pendingImages = pendingImagesMap.get(tag);
    if (pendingImages == null) {
        pendingImages = Collections.newSetFromMap(new WeakHashMap<ImageView, Boolean>()); // create weak set
        pendingImagesMap.put(tag, pendingImages);
        task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    }
    pendingImages.add(imageView);
    imageView.setTag(tag);
    imageView.setImageDrawable(null);
}
 

public static void maybeInvokeRetrieval(TextView textView,
                                        ParsedResult result,
                                        HistoryManager historyManager,
                                        Context context) {
  if (result instanceof URIParsedResult) {
    SupplementalInfoRetriever uriRetriever = 
        new URIResultInfoRetriever(textView, (URIParsedResult) result, historyManager, context);
    uriRetriever.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    SupplementalInfoRetriever titleRetriever = 
        new TitleRetriever(textView, (URIParsedResult) result, historyManager);
    titleRetriever.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
  } else if (result instanceof ProductParsedResult) {
    ProductParsedResult productParsedResult = (ProductParsedResult) result;
    String productID = productParsedResult.getProductID();
    SupplementalInfoRetriever productRetriever =
        new ProductResultInfoRetriever(textView, productID, historyManager, context);
    productRetriever.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
  } else if (result instanceof ISBNParsedResult) {
    String isbn = ((ISBNParsedResult) result).getISBN();
    SupplementalInfoRetriever productInfoRetriever = 
        new ProductResultInfoRetriever(textView, isbn, historyManager, context);
    productInfoRetriever.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    SupplementalInfoRetriever bookInfoRetriever = 
        new BookResultInfoRetriever(textView, isbn, historyManager, context);
    bookInfoRetriever.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
  }
}
 

private void initData()
{
	IMedia media = ((EditorActivityListener) a).media();

	String[] dateAndTime = TimeUtility.millisecondsToDatestampAndTimestamp(((EditorActivityListener) a).media().dcimEntry.timeCaptured);
	
	historyHeaderSubTitle.setText(getString(R.string.editor_image_taken, dateAndTime[0] + " " + dateAndTime[1]));

	AsyncTask<Void, Void, List<INotification>> taskLoadNotifications = new AsyncTask<Void, Void, List<INotification>>()
	{
		@Override
		protected List<INotification> doInBackground(Void... params) {
			return InformaCam.getInstance().notificationsManifest.sortBy(Models.INotificationManifest.Sort.DATE_DESC);
		}

		@Override
		protected void onPostExecute(List<INotification> result) {
			super.onPostExecute(result);
			lvHistory.setAdapter(new MediaHistoryListAdapter(a, ((EditorActivityListener) a).media()._id, result));	
			
			if (lvHistory.getAdapter().getCount() == 0)
			{
				historyHeader.setOnClickListener(null);
			//	showHistoryIndicator.setVisibility(View.GONE);
			}
			else
			{
				historyHeader.setOnClickListener(OverviewFormFragment.this);
			//	showHistoryIndicator.setVisibility(View.VISIBLE);
			}
		}		
	};
	taskLoadNotifications.execute((Void)null);
}
 

@SuppressLint("NewApi")
private void executeDownloadTask(ArrayList<PageModel> novels) {
	downloadTask = new DownloadNovelDetailsTask(this);
	String key = DisplayTeaserListActivity.TAG + ":" + novels.get(0).getPage();
	if (novels == null || novels.size() == 0) {
		Log.w(TAG, getResources().getString(R.string.error_empty_download_array));
		return;
	}
	if (novels.size() > 1) {
		key = DisplayTeaserListActivity.TAG + ":All_Teasers";
	}
	boolean isAdded = LNReaderApplication.getInstance().addTask(key, task);
	if (isAdded) {
		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
			downloadTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, novels.toArray(new PageModel[novels.size()]));
		else
			downloadTask.execute(novels.toArray(new PageModel[novels.size()]));
	} else {
		Log.i(TAG, "Continue download task: " + key);
		DownloadNovelDetailsTask tempTask = (DownloadNovelDetailsTask) LNReaderApplication.getInstance().getTask(key);
		if (tempTask != null) {
			downloadTask = tempTask;
			downloadTask.owner = this;
		}
		toggleProgressBar(true);
	}
}
 

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    mRecyclerView.setItemAnimator(new DefaultItemAnimator());
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

    setFastScrollColor(mFastScroll);
    mFastScroll.attachRecyclerView(mRecyclerView);

    mAsyncTask = new FAQsLoader().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
}
 

private synchronized void autoFocusAgainLater() {
    if (!stopped && outstandingTask == null) {
        AutoFocusTask newTask = new AutoFocusTask();
        try {
            if (Build.VERSION.SDK_INT >= 11) {
                newTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
            } else {
                newTask.execute();
            }
            outstandingTask = newTask;
        } catch (RejectedExecutionException ree) {
            Log.w(TAG, "Could not request auto focus", ree);
        }
    }
}
 

private synchronized void cancelOutstandingTask() {
    if (outstandingTask != null) {
        if (outstandingTask.getStatus() != AsyncTask.Status.FINISHED) {
            outstandingTask.cancel(true);
        }
        outstandingTask = null;
    }
}
 

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    mRecyclerView.setItemAnimator(new DefaultItemAnimator());
    mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(),
            getActivity().getResources().getInteger(R.integer.wallpapers_column_count)));
    mRecyclerView.setHasFixedSize(false);

    if (WallpaperBoardApplication.getConfig().getWallpapersGrid() ==
            WallpaperBoardConfiguration.GridStyle.FLAT) {
        int padding = getActivity().getResources().getDimensionPixelSize(R.dimen.card_margin);
        mRecyclerView.setPadding(padding, padding, 0, 0);
    }
    resetViewBottomPadding(mRecyclerView, true);

    mSwipe.setColorSchemeColors(ColorHelper.getAttributeColor(
            getActivity(), R.attr.colorAccent));
    mSwipe.setOnRefreshListener(() -> {
        if (mAsyncTask != null) {
            mSwipe.setRefreshing(false);
            return;
        }

        WallpapersLoaderTask.with(getActivity()).start();
        mAsyncTask = new WallpapersTask().executeOnExecutor(AsyncTask.SERIAL_EXECUTOR);
    });

    getWallpapers();
}
 

private synchronized void cancel() {
	AsyncTask<?, ?, ?> task = inactivityTask;
	if (task != null) {
		task.cancel(true);
		inactivityTask = null;
	}
}
 

private void finishEvent(final Event event) {
	// Send chosen event to the server
	List<String> userRecentEventInfo = new ArrayList<>();
	userRecentEventInfo.add(event.getRemoteId());
	new RecentEventTask(new AccountDelegate() {
		@Override
		public void finishAccount(AccountStatus accountStatus) {
			// no-op, don't care if server didn't get event selection
		}
	}, getApplicationContext()).execute(userRecentEventInfo.toArray(new String[userRecentEventInfo.size()]));

	try {
		UserHelper userHelper = UserHelper.getInstance(getApplicationContext());
		User user = userHelper.readCurrentUser();
		userHelper.setCurrentEvent(user, event);
	} catch (UserException e) {
		Log.e(LOG_NAME, "Could not set current event.", e);
	}

	// disable pushing locations
	if (!UserHelper.getInstance(getApplicationContext()).isCurrentUserPartOfEvent(event)) {
		SharedPreferences.Editor sp = PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).edit();
		sp.putBoolean(getString(R.string.reportLocationKey), false).apply();
	}


	AsyncTask.execute(new Runnable() {
		@Override
		public void run() {
			new ObservationServerFetch(getApplicationContext()).fetch(false);
		}
	});

	setResult(RESULT_OK);
	finish();
}
 

@SuppressLint("StaticFieldLeak")
@Override
public void onReceive(final Context context, Intent intent) {
  if (!CLEAR_ACTION.equals(intent.getAction()))
    return;

  final long[] threadIds = intent.getLongArrayExtra(THREAD_IDS_EXTRA);

  if (threadIds != null) {
    NotificationManagerCompat.from(context).cancel(intent.getIntExtra(NOTIFICATION_ID_EXTRA, -1));

    new AsyncTask<Void, Void, Void>() {
      @Override
      protected Void doInBackground(Void... params) {
        List<MarkedMessageInfo> messageIdsCollection = new LinkedList<>();

        for (long threadId : threadIds) {
          Log.i(TAG, "Marking as read: " + threadId);
          List<MarkedMessageInfo> messageIds = DatabaseFactory.getThreadDatabase(context).setRead(threadId, true);
          messageIdsCollection.addAll(messageIds);
        }

        process(context, messageIdsCollection);

        ApplicationDependencies.getMessageNotifier().updateNotification(context);

        return null;
      }
    }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
  }
}
 

/**
 * Handle the newly added key digit. Append the digit to {@link #mPinTyped}.
 * If the new digit is {@link KeyNamesBuilder#BACKSPACE_TITLE}, remove the last digit of the {@link #mPinTyped}.
 *
 * @param newDigit newly pressed digit
 */
private void onKeyPressed(@Nullable String newDigit) {
    if (newDigit == null) return;

    //Check for the state
    if (mAuthenticationListener == null) {
        throw new IllegalStateException("Set AuthenticationListener to receive callbacks.");
    }

    if (newDigit.equals(KeyNamesBuilder.BACKSPACE_TITLE)) { //Back space key is pressed.
        if (mPinTyped.size() > 0) mPinTyped.remove(mPinTyped.size() - 1);   //Remove last digit.
    } else {

        //Add new digit
        mPinTyped.add(mKeyNamesBuilder.getValueOfKey(newDigit));
    }

    invalidate();

    if (isDynamicPinEnabled() || mPinTyped.size() == mBoxIndicator.getPinLength()) {
        if (mPinAuthenticatorTask != null && mPinAuthenticatorTask.getStatus() == AsyncTask.Status.RUNNING)
            mPinAuthenticatorTask.cancel(true);

        mPinAuthenticatorTask = new PinAuthenticatorTask(mAuthenticator);
        //noinspection unchecked
        mPinAuthenticatorTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, mPinTyped);
    } else {
        giveTactileFeedbackForKeyPress();
    }

}