public void addDrawerListener(@NonNull DrawerListener listener) {
        if (listener == null) {
            return;
        }
        if (mListeners == null) {
            mListeners = new ArrayList<DrawerListener>();
        }
        mListeners.add(listener);
    }
Adds the specified listener to the list of listeners that will be notified of drawer events.

@param listener Listener to notify when drawer events occur.
@see #removeDrawerListener(DrawerListener)
app/src/main/java/com/sunnyweather/android/ui/customerUIs/HomeDrawerLayout.java