BottomNavigationView去掉动画效果

本来以为BottomNavigationView应该有自定义的方法可以改变这种默认的行为，结果人家官方压根没有提供，在stackoverflow上找到的最佳方案也是使用反射。

1.创建一个helper类

import android.support.design.internal.BottomNavigationItemView; 
import android.support.design.internal.BottomNavigationMenuView; 
import android.support.design.widget.BottomNavigationView; 
import android.util.Log;
import java.lang.reflect.Field;

public class BottomNavigationViewHelper { 
    public static void disableShiftMode(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);
                //noinspection RestrictedApi 
                item.setShiftingMode(false);
                // set once again checked value, so view will be updated 
                //noinspection RestrictedApi 
                item.setChecked(item.getItemData().isChecked());
            } 
        } catch (NoSuchFieldException e) {
            Log.e("BNVHelper", "Unable to get shift mode field", e);
        } catch (IllegalAccessException e) {
            Log.e("BNVHelper", "Unable to change value of shift mode", e);
        } 
    } 
}

2.使用

BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation_bar);
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);