KeyEvents handling from fragments - https://stackoverflow.com/a/43778858/2489474

KeyEventHandlingFragment.java

public abstract class KeyEventHandlingFragment extends Fragment
        implements KeyEventPassingActivity.KeyEventListener {

    @SuppressWarnings("deprecation")
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        if (activity instanceof KeyEventPassingActivity) {
            ((KeyEventPassingActivity) activity).addKeyEventHandler(this);
        }
    }

    @Override
    public void onDetach() {
        Activity activity = getActivity();
        if (activity instanceof KeyEventPassingActivity) {
            ((KeyEventPassingActivity) activity).removeKeyEventHandler(this);
        }
        super.onDetach();
    }
}

KeyEventPassingActivity.java

public abstract class KeyEventPassingActivity extends Activity {

    public interface KeyEventListener extends View.OnKeyListener {
        boolean isVisible();
        View getView();
    }

    private final List<KeyEventListener> keyEventHandlerList = new ArrayList<>();

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        for (KeyEventListener handler : keyEventHandlerList) {
            if (handleKeyEvent(handler, event)) {
                return true;
            }
        }
        return super.dispatchKeyEvent(event);
    }

    void addKeyEventHandler(@NonNull KeyEventListener handler) {
        keyEventHandlerList.add(handler);
    }

    void removeKeyEventHandler(@NonNull KeyEventListener handler) {
        keyEventHandlerList.remove(handler);
    }

    /**
     * @return <tt>true</tt> if the event was handled, <tt>false</tt> otherwise
     */
    private boolean handleKeyEvent(@Nullable KeyEventListener listener, KeyEvent event) {
        return listener != null
                && listener.isVisible()
                && listener.onKey(listener.getView(), event.getKeyCode(), event);
    }
}