导航视图中的当前菜单项视图始终为空

Question

我正在使用导航视图。由于某种原因，我无法获得菜单项的视图。它始终为空。我试过viewobserver，findViewByid，但它没有用。我需要在执行项目选择事件时获得当前菜单项位置的y coord。这可能吗？

初始化抽屉

 activity.drawerIndicator.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (activity.drawerLayout.isDrawerVisible(GravityCompat.START)) {
                    activity.drawerLayout.closeDrawer(GravityCompat.START);
                } else {
                    activity.drawerLayout.openDrawer(GravityCompat.START);
                }
            }
        });
        activity.drawerLayout.setDrawerListener(new DrawerLayout.DrawerListener() {
            @Override
            public void onDrawerSlide(View view, float v) {

            }

            @Override
            public void onDrawerOpened(View view) {
                activity.closeKeyboard();
            }

            @Override
            public void onDrawerClosed(View view) {
                // your refresh code can be called from here
                //activity.closeKeyboard();
            }

            @Override
            public void onDrawerStateChanged(int i) {

            }
        });

初始化导航视图

public void initNavigationView() {
        activity.navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
             // This method will trigger on item Click of navigation menu
             @Override
             public boolean onNavigationItemSelected(MenuItem menuItem) {
                 //Closing drawer on item click
                 final int itemId=menuItem.getItemId();

                 final ViewTreeObserver viewTreeObserver =activity.navigationView.getViewTreeObserver();

                 viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                     @Override
                     public void onGlobalLayout() {
                         View menuButton = activity.findViewById(itemId);
                         // This could be called when the button is not there yet, so we must test for null
                         if (menuButton != null) {
                             // Found it! Do what you need with the button

                             int[] location = new int[2];
                             menuButton.getLocationInWindow(location);

                             SharedPreferencesController.getInstance(activity.getApplicationContext()).setTopPosition(location[1]);

                             // Now you can get rid of this listener
                             viewTreeObserver.removeGlobalOnLayoutListener(this);
                         }
                     }
                 });

                 activity.drawerLayout.closeDrawers();




                 switch (menuItem.getItemId()) {

                     case R.id.checkin:
                         if (!menuItem.isChecked())
                             menuItem.setChecked(true);
                         return goToCheckinItemMenu();
                     case R.id.boarding_passes:
                         return goToBoardingPassesItemMenu(menuItem);
                     case R.id.flight_status:
                         return goToFlightStatusItemMenu(menuItem);
                     case R.id.timetable:
                         return goToTimetableItemMenu(menuItem);
                     case R.id.promotion:
                         return goToPromotionItemMenu(menuItem);
                     //case R.id.reccomend_app:
                     //    return goToReccomendAppItemMenu();
                     case R.id.about_app:
                         return goToAboutAppItemMenu(menuItem);
                     case R.id.contact_us:
                         return goToContactUsItemMenu(menuItem);
                     case R.id.settings:
                         return goToSettingsItemMenu(menuItem);
                     case R.id.data_protection:
                         return goToDataProtectionItemMenu(menuItem);
                     case R.id.checkin_info:
                         return goToCheckinInfoItemMenu(menuItem);
                     case R.id.panorama:
                         return goToPanoramaCLubItemMenu();
                     default:
                         Toast.makeText(activity.getApplicationContext(), "Somethings Wrong", Toast.LENGTH_SHORT).show();
                         return true;
                 }
             }
         }
        );
    }

如您所见，我试图使用TreeObserver在屏幕上获取menuItem的当前位置。我知道观察者在事情发生后会起作用，这意味着它在被叫之后无法正常工作。但无论如何，menuButton视图始终为null