//用这个控件需要添加 design包: implementation 'com.android.support:design:26.1.0'
//版本号和compileSdkVersion的版本号相关<android.support.design.widget.BottomNavigationViewandroid:id="@+id/bnvBottomBar"android:layout_width="match_parent"android:layout_height="50dp"android:background="#bb88f7ff"app:menu="@menu/bottom_bar" />

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"><itemandroid:id="@+id/navigation_home"android:icon="@drawable/home"android:title="home" /><itemandroid:id="@+id/navigation_msg"android:icon="@drawable/msg"android:title="msg" /><itemandroid:id="@+id/navigation_info"android:icon="@drawable/info"android:title="info" /><itemandroid:id="@+id/navigation_set"android:icon="@drawable/set"android:title="set" /><itemandroid:id="@+id/navigation_me"android:icon="@drawable/me"android:title="me" />
</menu>

//声明
private BottomNavigationView bnvBottomBar;//查找控件
bnvBottomBar = (BottomNavigationView) findViewById(R.id.bnvBottomBar);disableShiftingMode(bnvBottomBar);  //禁止偏移   -------->> 方法在后面
//disableItemScale(bnvBottomBar);   //禁止放大   -------->> 方法在后面//监听事件
bnvBottomBar.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {@Overridepublic boolean onNavigationItemSelected(@NonNull MenuItem item) {switch (item.getItemId()) {case R.id.navigation_home:Toast.makeText(MainActivity.this, "home", Toast.LENGTH_SHORT).show();break;case R.id.navigation_info:Toast.makeText(MainActivity.this, "info", Toast.LENGTH_SHORT).show();break;case R.id.navigation_msg:Toast.makeText(MainActivity.this, "msg", Toast.LENGTH_SHORT).show();break;case R.id.navigation_set:Toast.makeText(MainActivity.this, "set", Toast.LENGTH_SHORT).show();break;case R.id.navigation_me:Toast.makeText(MainActivity.this, "me", Toast.LENGTH_SHORT).show();break;}return true; //返回true, 返回false点击item没有任何效果
    }
});//点击切换item
bnvBottomBar.setSelectedItemId(R.id.navigation_home);

/*** 禁用item>=3时的平移及缩放(没有平移效果了, 但是图标和文字还有放大效果)* 出处: https://blog.csdn.net/zzyawei/article/details/81082257*/
@SuppressLint("RestrictedApi")
public static void disableShiftingMode(BottomNavigationView view) {try {BottomNavigationMenuView mMenuView = (BottomNavigationMenuView) view.getChildAt(0);Field mShiftingModeField = BottomNavigationMenuView.class.getDeclaredField("mShiftingMode");mShiftingModeField.setAccessible(true);mShiftingModeField.set(mMenuView, false);for (int i = 0; i < mMenuView.getChildCount(); i++) {BottomNavigationItemView itemView = (BottomNavigationItemView) mMenuView.getChildAt(i);itemView.setShiftingMode(false);itemView.setChecked(itemView.getItemData().isChecked());}} catch (Exception e) {e.printStackTrace();}
}

/*** 禁用item 缩放动画（选中放大图标/文字 ---->> 图片静止不再放大, 文字会有细微的放大效果）* 出处: https://blog.csdn.net/zzyawei/article/details/81082257*/
@SuppressLint("RestrictedApi")
public static void disableItemScale(BottomNavigationView view) {try {BottomNavigationMenuView menuView = (BottomNavigationMenuView) view.getChildAt(0);Field mLargeLabelField = BottomNavigationItemView.class.getDeclaredField("mLargeLabel");Field mSmallLabelField = BottomNavigationItemView.class.getDeclaredField("mSmallLabel");Field mShiftAmountField = BottomNavigationItemView.class.getDeclaredField("mShiftAmount");Field mScaleUpFactorField = BottomNavigationItemView.class.getDeclaredField("mScaleUpFactor");Field mScaleDownFactorField = BottomNavigationItemView.class.getDeclaredField("mScaleDownFactor");mSmallLabelField.setAccessible(true);mLargeLabelField.setAccessible(true);mShiftAmountField.setAccessible(true);mScaleUpFactorField.setAccessible(true);mScaleDownFactorField.setAccessible(true);final float fontScale = view.getResources().getDisplayMetrics().scaledDensity;for (int i = 0; i < menuView.getChildCount(); i++) {BottomNavigationItemView itemView = (BottomNavigationItemView) menuView.getChildAt(i);TextView lagerObj = (TextView) mLargeLabelField.get(itemView);TextView smallObj = (TextView) mSmallLabelField.get(itemView);lagerObj.setTextSize(smallObj.getTextSize() / fontScale + 0.5f);mShiftAmountField.set(itemView, 0);mScaleUpFactorField.set(itemView, 1f);mScaleDownFactorField.set(itemView, 1f);itemView.setChecked(itemView.getItemData().isChecked());}} catch (Exception e) {e.printStackTrace();}
}