How to use

from

method

in

androidx.core.app.NotificationManagerCompat

final NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);

public static void dismissNotification(Context ctx, int groupId) {
  NotificationManagerCompat notificationManager = NotificationManagerCompat.from(ctx);
  notificationManager.cancel(groupId);
}

private static void publishNotification(Context ctx, Notification notification, int groupId) {
  NotificationManagerCompat notificationManager = NotificationManagerCompat.from(ctx);
  notificationManager.notify(groupId, notification);
}

/**
 * 通知発行用のヘルパークラス
 * @param context
 * @param tag
 * @param notificationId
 * @param notification
 */
private static void notify(@NonNull final Context context,
  @Nullable final String tag, final int notificationId,
  @NonNull final Notification notification) {
  
  NotificationManagerCompat.from(context)
    .notify(tag, notificationId, notification);
}

/**
 * Handles action Dismiss in the provided background thread.
 */
private void handleActionDismiss() {
  Log.d(TAG, "handleActionDismiss()");
  NotificationManagerCompat notificationManagerCompat =
      NotificationManagerCompat.from(getApplicationContext());
  notificationManagerCompat.cancel(StandaloneMainActivity.NOTIFICATION_ID);
}

/**
 * Handles action Dismiss in the provided background thread.
 */
private void handleActionDismiss() {
  Log.d(TAG, "handleActionDismiss()");
  NotificationManagerCompat notificationManagerCompat =
      NotificationManagerCompat.from(getApplicationContext());
  notificationManagerCompat.cancel(MainActivity.NOTIFICATION_ID);
}

public void cancelNotification(Context context) {
  boolean updateSummary = false;
  synchronized (this) {
    mMessages.clear();
  }
  synchronized (mShowingNotificationLock) {
    // cancel the notification
    if (mShowingNotification) {
      NotificationManagerCompat.from(context).cancel(mNotificationId);
      mShowingNotification = false;
      updateSummary = true;
    }
  }
  if (updateSummary)
    NotificationManager.getInstance().updateSummaryNotification(context, null);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  mMainRelativeLayout = (RelativeLayout) findViewById(R.id.mainRelativeLayout);
  mNotificationDetailsTextView = (TextView) findViewById(R.id.notificationDetails);
  mSpinner = (Spinner) findViewById(R.id.spinner);
  mNotificationManagerCompat = NotificationManagerCompat.from(getApplicationContext());
  // Create an ArrayAdapter using the string array and a default spinner layout.
  ArrayAdapter<CharSequence> adapter =
      new ArrayAdapter(
          this,
          android.R.layout.simple_spinner_item,
          NOTIFICATION_STYLES);
  // Specify the layout to use when the list of choices appears.
  adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  // Apply the adapter to the spinner.
  mSpinner.setAdapter(adapter);
  mSpinner.setOnItemSelectedListener(this);
}

public void setOpened(Context context, boolean opened) {
  boolean updateSummary = false;
  synchronized (this) {
    mOpened = opened;
    if (mOpened) {
      mMessages.clear();
      synchronized (mShowingNotificationLock) {
        // cancel the notification
        if (mShowingNotification) {
          NotificationManagerCompat.from(context).cancel(mNotificationId);
          mShowingNotification = false;
          updateSummary = true;
        }
      }
    }
  }
  if (updateSummary)
    NotificationManager.getInstance().updateSummaryNotification(context, null);
}

/**
 * Handles action Snooze in the provided background thread.
 */
private void handleActionSnooze() {
  Log.d(TAG, "handleActionSnooze()");
  // You could use NotificationManager.getActiveNotifications() if you are targeting SDK 23
  // and above, but we are targeting devices with lower SDK API numbers, so we saved the
  // builder globally and get the notification back to recreate it later.
  NotificationCompat.Builder notificationCompatBuilder =
      GlobalNotificationBuilder.getNotificationCompatBuilderInstance();
  // Recreate builder from persistent state if app process is killed
  if (notificationCompatBuilder == null) {
    // Note: New builder set globally in the method
    notificationCompatBuilder = recreateBuilderWithBigTextStyle();
  }
  Notification notification;
  notification = notificationCompatBuilder.build();
  if (notification != null) {
    NotificationManagerCompat notificationManagerCompat =
        NotificationManagerCompat.from(getApplicationContext());
    notificationManagerCompat.cancel(MainActivity.NOTIFICATION_ID);
    try {
      Thread.sleep(SNOOZE_TIME);
    } catch (InterruptedException ex) {
      Thread.currentThread().interrupt();
    }
    notificationManagerCompat.notify(MainActivity.NOTIFICATION_ID, notification);
  }
}

/**
 * Handles action Snooze in the provided background thread.
 */
private void handleActionSnooze() {
  Log.d(TAG, "handleActionSnooze()");
  // You could use NotificationManager.getActiveNotifications() if you are targeting SDK 23
  // and above, but we are targeting devices with lower SDK API numbers, so we saved the
  // builder globally and get the notification back to recreate it later.
  NotificationCompat.Builder notificationCompatBuilder =
      GlobalNotificationBuilder.getNotificationCompatBuilderInstance();
  // Recreate builder from persistent state if app process is killed
  if (notificationCompatBuilder == null) {
    // Note: New builder set globally in the method
    notificationCompatBuilder = recreateBuilderWithBigTextStyle();
  }
  Notification notification;
  notification = notificationCompatBuilder.build();
  if (notification != null) {
    NotificationManagerCompat notificationManagerCompat =
        NotificationManagerCompat.from(getApplicationContext());
    notificationManagerCompat.cancel(StandaloneMainActivity.NOTIFICATION_ID);
    try {
      Thread.sleep(SNOOZE_TIME);
    } catch (InterruptedException ex) {
      Thread.currentThread().interrupt();
    }
    notificationManagerCompat.notify(StandaloneMainActivity.NOTIFICATION_ID, notification);
  }
}

@Override
public void onMessageSent() {
  NotificationManagerCompat notificationManager =
      NotificationManagerCompat.from(mContext);
  notificationManager.cancel(mNotificationId);
  NotificationManager.getInstance().onNotificationDismissed(mContext, mConnection,
      mChannel);
  NotificationManager.getInstance().updateSummaryNotification(mContext, null);
}

    NotificationManagerCompat.from(getApplicationContext());
notificationManagerCompat.notify(MainActivity.NOTIFICATION_ID, updatedNotification);

    NotificationManagerCompat.from(getApplicationContext());
notificationManagerCompat.notify(
    StandaloneMainActivity.NOTIFICATION_ID,

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_weather);
mManager = NotificationManagerCompat.from(this);
preferences = new Prefs(this);
toolbar = findViewById(R.id.toolbar);

    NotificationManagerCompat.from(getApplicationContext());
notificationManagerCompat.notify(MainActivity.NOTIFICATION_ID, notification);

    NotificationManagerCompat.from(getApplicationContext());
notificationManagerCompat.notify(StandaloneMainActivity.NOTIFICATION_ID, notification);

  NotificationManagerCompat.from(context).cancel(CHAT_SUMMARY_NOTIFICATION_ID);
  return;
      .setContentIntent(intent);
NotificationManagerCompat.from(context).notify(CHAT_SUMMARY_NOTIFICATION_ID, notification.build());

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  Log.d(TAG, "onCreate()");
  setContentView(R.layout.activity_main);
  // Enables Ambient mode.
  mAmbientController = AmbientMode.attachAmbientSupport(this);
  mNotificationManagerCompat = NotificationManagerCompat.from(getApplicationContext());
  mMainFrameLayout = findViewById(R.id.mainFrameLayout);
  mWearableRecyclerView = findViewById(R.id.recycler_view);
  // Aligns the first and last items on the list vertically centered on the screen.
  mWearableRecyclerView.setEdgeItemsCenteringEnabled(true);
  // Customizes scrolling so items farther away form center are smaller.
  ScalingScrollLayoutCallback scalingScrollLayoutCallback =
      new ScalingScrollLayoutCallback();
  mWearableRecyclerView.setLayoutManager(
      new WearableLinearLayoutManager(this, scalingScrollLayoutCallback));
  // Improves performance because we know changes in content do not change the layout size of
  // the RecyclerView.
  mWearableRecyclerView.setHasFixedSize(true);
  // Specifies an adapter (see also next example).
  mCustomRecyclerAdapter = new CustomRecyclerAdapter(
      NOTIFICATION_STYLES,
      // Controller passes selected data from the Adapter out to this Activity to trigger
      // updates in the UI/Notifications.
      new Controller(this));
  mWearableRecyclerView.setAdapter(mCustomRecyclerAdapter);
}

Event event = AppDatabase.getInstance(this).getScheduleDao().getEvent(eventId);
if (event != null) {
  NotificationManagerCompat.from(this).notify((int) eventId, buildNotification(event));