BottomNavigationView(下方按钮)

在布局中写入

ViewPager
   <com.example.wanandroid.ui.fragment.ScrollableViewPager
            android:id="@+id/vp"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_above="@+id/bnv"
            android:layout_below="@+id/toolbar"
            android:layout_alignParentStart="true"
            android:layout_alignParentLeft="true" />




<android.support.design.widget.BottomNavigationView
            android:id="@+id/bnv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            app:itemBackground="@android:color/white"
            //可以设置动画样式
            app:labelVisibilityMode="labeled"
            //文字颜色
            app:itemTextColor="@drawable/select_textcolor"
             //图片颜色
            app:itemIconTint="@drawable/select_textcolor"
            //设置数据
            app:menu="@menu/nav_menu"/>

在Xml中写入

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/home"
        android:icon="@drawable/rb_shouye"
        android:title="首页"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/guide"
        android:icon="@drawable/rb_tixi"
        android:title="知识体系"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/msg"
        android:icon="@drawable/ic_wx_article"
        android:title="公众号"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/person"
        android:icon="@drawable/rb_daohang"
        android:title="导航"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/sett"
        android:icon="@drawable/rb_xiangmu"
        android:title="项目"
        app:showAsAction="ifRoom" />

</menu>

在代码里写入

  mVp.addOnPageChangeListener (new ViewPager.OnPageChangeListener () {
          @Override
          public void onPageScrolled(int i, float v, int i1) {

          }

          @Override
          public void onPageSelected(int i) {
              mBnv.getMenu ().getItem (i).setChecked (true);
          }

          @Override
          public void onPageScrollStateChanged(int i) {

          }
      });
      // 为bnv设置选择监听事件
      mBnv.setOnNavigationItemSelectedListener (new BottomNavigationView.OnNavigationItemSelectedListener () {
          @Override
          public boolean onNavigationItemSelected(@NonNull MenuItem item) {
              switch (item.getItemId ()) {
                  case R.id.home:
                      // 跳转到对应的页面
                      mVp.setCurrentItem (0);
                      break;
                  case R.id.guide:
                      mVp.setCurrentItem (1);
                      break;
                  case R.id.msg:
                      mVp.setCurrentItem (2);
                      break;
                  case R.id.person:
                      mVp.setCurrentItem (3);
                      break;
                  case R.id.sett:
                      mVp.setCurrentItem (4);
                      break;
              }
              // 这里必须返回true才能响应点击事件
              return true;
          }
      });

所遇问题归纳

注意 ：底部Bottom选项，最少为3项，超过3项之后,BottomNavigationView会自动使用本身控件的自带动画属性，同时最多好像为5项，目前没有进行验证。
如果想要图标本身的颜色就加

mBottomNV = (BottomNavigationView) findViewById(R.id.bottom_navigation);
mBottomNV.setItemIconTintList(null);

问题 ：当底部Button超过三个之后，自带动画效果
需求 ：取消原有动画效果，常规显示

解决方式 ：

创建BottomNavigationViewHelper类，进行disableShiftMode方法调用

public class BottomNavigationViewHelper {
    @SuppressLint("RestrictedApi")
    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.setShifting (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);
        }
    }
}

设置BottomNavigationView展示类型

        BottomNavigationView mBv = (BottomNavigationView) findViewById(R.id.bv);
        //调用上面的类进行设置
        BottomNavigationViewHelper.disableShiftMode(mBv);