Remove Animation/Shifting mode from BottomNavigati

问题:

This question already has an answer here:

• How to disable BottomNavigationView shift mode? 16 answers

i am building an application in which i have a BottomNavigationView. Everything works fine until i get to the Activity.

The Navigation is this:

The problem is that it has this default animation so it pushes the active element everytime higher than the rest.

Another Example:

So my question is how to get rid of this default animation and every item is aligned when i switch between them?

My code:

public class MainActivity extends AppCompatActivity {
    private BottomNavigationView bottomNavigationView;
    private Fragment fragment;
    private FragmentManager fragmentManager;
    private FragmentTransaction transaction;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setupBottomBar();
    }

    private void setupBottomBar() {
        bottomNavigationView = (BottomNavigationView)findViewById(R.id.bottomBar);
        fragmentManager = getSupportFragmentManager();
        fragment = new CardDeckFragment();
        transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.activity_main, fragment).commit();
        bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                switch (item.getItemId()){
                    case R.id.action_card_deck:{
                        Toast.makeText(MainActivity.this, "Card Deck Selected", Toast.LENGTH_SHORT).show();
                        fragment = new CardDeckFragment();
                        break;
                    }
                    case R.id.action_favorites:{
                        Toast.makeText(MainActivity.this, "Favorites Selected", Toast.LENGTH_SHORT).show();
                        fragment = new FavoritesFragment();
                        break;
                    }
                    case R.id.action_favorites_another:{
                        Toast.makeText(MainActivity.this, "Image Selected", Toast.LENGTH_SHORT).show();
                        fragment = new ImageFragment();
                        break;
                    }
                    case R.id.action_profile:{
                        Toast.makeText(MainActivity.this, "Profile Selected", Toast.LENGTH_SHORT).show();
                        fragment = new ProfileFragment();
                        break;
                    }
                    case R.id.action_menu:{
                        Toast.makeText(MainActivity.this, "Menu Selected", Toast.LENGTH_SHORT).show();
                        fragment = new MenuFragment();
                        break;
                    }
                }

                transaction = fragmentManager.beginTransaction();
                transaction.replace(R.id.activity_main, fragment).commit();
                return true;
            }
        });



    }
}

and my layout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.realtimegaming.androidnative.testproject.MainActivity">

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/bottomBar"
        android:layout_alignParentBottom="true"
        android:background="@color/brown"
        android:layout_gravity="bottom"
        android:gravity="bottom"
        android:layout_marginTop="?attr/actionBarSize"
        app:itemBackground="@color/colorPrimary"
        app:menu="@menu/bottom_navigation_main"
        app:itemIconTint="@color/white"
        android:fitsSystemWindows="true"
        android:animateLayoutChanges="false"
        android:splitMotionEvents="false"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</RelativeLayout>

回答1:

Ok i found a way in case it helps someone else. So by default BottomNavigationView add shiftingmode = true when its more than 3 items.

At this moment you cannot change it through existing API and the only way to disable shift mode is to use reflection.

So we can use this helper to get rid of this:

class BottomNavigationViewHelper {

    static void removeShiftMode(BottomNavigationView view) {
        BottomNavigationMenuView menuView = (BottomNavigationMenuView) view.getChildAt(0);
        try {
            Field shiftingMode = menuView.getClass().getDeclaredField("mShiftingMode");
            shiftingMode.setAccessible(true);
            shiftingMode.setBoolean(menuView, false);
            shiftingMode.setAccessible(false);
            for (int i = 0; i < menuView.getChildCount(); i++) {
                BottomNavigationItemView item = (BottomNavigationItemView) menuView.getChildAt(i);
                item.setShiftingMode(false);
                // set once again checked value, so view will be updated
                item.setChecked(item.getItemData().isChecked());
            }
        } catch (NoSuchFieldException e) {
            Log.e("ERROR NO SUCH FIELD", "Unable to get shift mode field");
        } catch (IllegalAccessException e) {
            Log.e("ERROR ILLEGAL ALG", "Unable to change value of shift mode");
        }
    }
}

and then use it like this:

BottomNavigationView bottomNavigationView = (BottomNavigationView)findViewById(R.id.bottomBar);
BottomNavigationViewHelper.removeShiftMode(bottomNavigationView);

Hope this helps someone with the same problem with me!!!

Remember, you'll need to execute this method each time you change menu items in your BottomNavigationView.

UPDATE

As per different stackoverflow question, you also need to update proguard configuration file (e.g. proguard-rules.pro), code above uses reflection and won't work if proguard obfuscate the mShiftingMode field.

-keepclassmembers class android.support.design.internal.BottomNavigationMenuView { 
    boolean mShiftingMode; 
}