BottomNavigationView最新用法

Android中使用BottomNavigationView早已不稀奇，之前其他博客也都介绍的有用法。
但是，现在网上所出现的使用方法已不符合当今需要
方法一 (com.android.support:design 版本不高于 27.0.3) 网上一堆
方法二 (com.android.support:design 版本高于 27.0.3) 网上没有任何说明
故，在此特别介绍一下 方法二 以供参考
此方法仅针对 Gradle 文件引用 com.android.support:design 版本不高于 27.0.3
⓵ 对于 Item>3 时的平移及缩放动画的处理
⓶ 对于 Item 缩放动画（选中放大图标/文字）
对于 Item>3 时的平移及缩放动画的处理
@SuppressLint("RestrictedApi")
public static void disableShiftMode(BottomNavigationView navigationView) {
    try {
        BottomNavigationMenuView menuView = (BottomNavigationMenuView) navigationView.getChildAt(0);
        Field mShiftingMode  = menuView.getClass().getDeclaredField("mShiftingMode");
        mShiftingMode.setAccessible(true);
        mShiftingMode.setBoolean(menuView, false);
        mShiftingMode.setAccessible(false);
        for (int i = 0; i < menuView.getChildCount(); i++) {
            BottomNavigationItemView itemView = (BottomNavigationItemView) menuView.getChildAt(i);
            itemView.setShifting(false);
            itemView.setEnabled(true);
            itemView.setChecked(itemView.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);
对于 Item 缩放动画（选中放大图标/文字）
@SuppressLint("RestrictedApi")
public static void disableItemScale(BottomNavigationView view) {
    try {
        BottomNavigationMenuView menuView = (BottomNavigationMenuView) view.getChildAt(0);
        Field mLargeLabelField = menuView.getClass().getDeclaredField("mLargeLabel");
        Field mSmallLabelField = menuView.getClass().getDeclaredField("mSmallLabel");
        Field mShiftAmountField = menuView.getClass().getDeclaredField("mShiftAmount");
        Field mScaleUpFactorField = menuView.getClass().getDeclaredField("mScaleUpFactor");
        Field mScaleDownFactorField = menuView.getClass().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 (NoSuchFieldException | IllegalAccessException e) {
        e.printStackTrace();
然后初始化后调用
// 默认count>3时选中效果会影响ViewPager的滑动切换效果，故利用反射去掉
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
// 本人没有关闭图标缩放动能，该方法不用
// BottomNavigationViewHelper.disableItemScale(bottomNavigationView);
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".activity.MainActivity">
    <com.xxx.xxxxx.view.NoScrollViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
    <android.support.design.widget.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="@color/colorAppBackground"
        app:itemIconTint="@drawable/main_view"
        app:itemTextColor="@drawable/main_view"
        app:menu="@menu/main_navigation" />
</LinearLayout>
Menu文件
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
        android:id="@+id/menu_home"
        android:icon="@drawable/icon_main_home"
        android:orderInCategory="1"
        android:title="资讯" />
        android:id="@+id/menu_product"
        android:icon="@drawable/icon_main_product"
        android:orderInCategory="2"
        android:title="项目" />
        android:id="@+id/menu_lease"
        android:icon="@drawable/icon_main_lease"
        android:orderInCategory="4"
        android:title="租房" />
        android:id="@+id/menu_mine"
        android:icon="@drawable/icon_main_mine"
        android:orderInCategory="5"
        android:title="我的" />
</menu>
Selector文件
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:color="@color/colorPrimary" android:state_checked="true" />
    <item android:color="@color/colorSecondary" />
</selector>
效果如图：
☠ But！ 在 com.android.support:design 版本高于 27.0.3 之后，这个方法失效，这也是我接下来着重介绍 方法二 的原因

此方法仅针对 Gradle 文件引用 com.android.support:design 版本高于 27.0.3

首先看一下源码

当 com.android.support:design <= 27.0.3 时
BottomNavigationMenuView 中源码
public class BottomNavigationMenuView extends ViewGroup implements MenuView {
    // ...
    // 就是这个属性
    private boolean mShiftingMode = true;
    // ...
    public void buildMenuView() {
        //...
        mButtons = new BottomNavigationItemView[mMenu.size()];
        // 为什么item大于3的时候，会有缩放
        mShiftingMode = mMenu.size() > 3;
        for (int i = 0; i < mMenu.size(); i++) {
            BottomNavigationItemView child = getNewItem();
            child.setShiftingMode(mShiftingMode);
            //...            
BottomNavigationItemView 中源码
public class BottomNavigationItemView extends FrameLayout implements MenuView.ItemView {
    private final int mShiftAmount;
    private final float mScaleUpFactor;
    private final float mScaleDownFactor;
    private boolean mShiftingMode;
    public BottomNavigationItemView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        final Resources res = getResources();
        int inactiveLabelSize = res.getDimensionPixelSize(R.dimen.design_bottom_navigation_text_size);
          int activeLabelSize = res.getDimensionPixelSize( R.dimen.design_bottom_navigation_active_text_size);
        mDefaultMargin = res.getDimensionPixelSize(R.dimen.design_bottom_navigation_margin);
        mShiftAmount = inactiveLabelSize - activeLabelSize;
        mScaleUpFactor = 1f * activeLabelSize / inactiveLabelSize;
        mScaleDownFactor = 1f * inactiveLabelSize / activeLabelSize;
        LayoutInflater.from(context).inflate(R.layout.design_bottom_navigation_item, this, true);
        setBackgroundResource(R.drawable.design_bottom_navigation_item_background);
        mIcon = findViewById(R.id.icon);
        mSmallLabel = findViewById(R.id.smallLabel);
        mLargeLabel = findViewById(R.id.largeLabel);
    @Override
    public void setChecked(boolean checked) {
        if (mShiftingMode) {
            if (checked) {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
                iconParams.topMargin = mDefaultMargin;
                mIcon.setLayoutParams(iconParams);
                mLargeLabel.setVisibility(VISIBLE);
                mLargeLabel.setScaleX(1f);
                mLargeLabel.setScaleY(1f);
            } else {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER;
                iconParams.topMargin = mDefaultMargin;
                mIcon.setLayoutParams(iconParams);
                // ShiftingMode模式下，不选中文字隐藏
                mLargeLabel.setVisibility(INVISIBLE);
                mLargeLabel.setScaleX(0.5f);
                mLargeLabel.setScaleY(0.5f);
            mSmallLabel.setVisibility(INVISIBLE);
        } else {
            if (checked) {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
                // 通过设置mShiftAmount 的大小 控制图片margin，进而控制图片大小
                iconParams.topMargin = mDefaultMargin + mShiftAmount;
                mIcon.setLayoutParams(iconParams);
                // 通过设置mLargeLabel和mSmallLabel的显示与隐藏控制文本大小
                // 如果把他俩TextSize设置为一样。则就不会变化
                mLargeLabel.setVisibility(VISIBLE);
                mSmallLabel.setVisibility(INVISIBLE);
                mLargeLabel.setScaleX(1f);
                mLargeLabel.setScaleY(1f);
                mSmallLabel.setScaleX(mScaleUpFactor);
                mSmallLabel.setScaleY(mScaleUpFactor);
            } else {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
                iconParams.topMargin = mDefaultMargin;
                mIcon.setLayoutParams(iconParams);
                mLargeLabel.setVisibility(INVISIBLE);
                mSmallLabel.setVisibility(VISIBLE);
                mLargeLabel.setScaleX(mScaleDownFactor);
                mLargeLabel.setScaleY(mScaleDownFactor);
                mSmallLabel.setScaleX(1f);
                mSmallLabel.setScaleY(1f);
        refreshDrawableState();
当 com.android.support:design > 27.0.3 时
BottomNavigationMenuView 中源码
public class BottomNavigationMenuView extends ViewGroup implements MenuView {
    // ...
    // mShiftingMode属性消失，取而代之的是这两个属性
    // itemHorizontalTranslationEnabled:是否启用水平移动动画（如果允许图标会有少许水平移动）
       private boolean itemHorizontalTranslationEnabled;
    // labelVisibilityMode:标签显示模式（labeled:显示标签，auto:根据标签个数判断是否显示，selected:选中的显示，unlabeled:不显示）
    private int labelVisibilityMode;
    // ...
    public void buildMenuView() {
        //...
        if (this.menu.size() == 0) {
            this.selectedItemId = 0;
            this.selectedItemPosition = 0;
            this.buttons = null;
        } else {
            this.buttons = new BottomNavigationItemView[this.menu.size()];
            boolean shifting = this.isShifting(this.labelVisibilityMode, this.menu.getVisibleItems().size());
            for(i = 0; i < this.menu.size(); ++i) {
                this.presenter.setUpdateSuspended(true);
                this.menu.getItem(i).setCheckable(true);
                this.presenter.setUpdateSuspended(false);
                BottomNavigationItemView child = this.getNewItem();
                //...            
    //...
    private boolean isShifting(int labelVisibilityMode, int childCount) {
        // 这个地方很奇怪，看了BottomNavigationItem中对labelVisibilityMode做了对应处理才明白
        // 默认labelVisibilityMode为"auto",也就是"-1",如果Item>3默认开启水平动画，否则关闭水平动画。
        // 如果labelVisibilityMode用户主动设置了值，且不为"auto"，只在"selected"模式下开启动画
        // "labeled"和"unlabeled"两种模式都不开启动画
        return labelVisibilityMode == -1 ? childCount > 3 : labelVisibilityMode == 0;
    //...
要想彻底关闭水平滑动动画，前提还要同时满足 itemHorizontalTranslationEnabled = false 
//...
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int width = MeasureSpec.getSize(widthMeasureSpec);
       int visibleCount = this.menu.getVisibleItems().size();
       int totalCount = this.getChildCount();
       int heightSpec = MeasureSpec.makeMeasureSpec(this.itemHeight, 1073741824);
       int totalWidth;
       int i;
       int extra;
       int i;
    // 两个条件都不满足才能禁止水平动画
    if (this.isShifting(this.labelVisibilityMode, visibleCount) && this.itemHorizontalTranslationEnabled) {
        View activeChild = this.getChildAt(this.selectedItemPosition);
           i = this.activeItemMinWidth;
           if (activeChild.getVisibility() != 8) {
               activeChild.measure(MeasureSpec.makeMeasureSpec(this.activeItemMaxWidth, -2147483648), heightSpec);
               i = Math.max(i, activeChild.getMeasuredWidth());
        //...                    
//...
BottomNavigationItemView 中对 labelVisibilityMode 也做了对应处理
//...            
// labelVisibilityMode="auto"时，值为-1
// labelVisibilityMode="selected"时，值为0
// labelVisibilityMode="labeled"时，值为1
// labelVisibilityMode="unlabeled"时，值为2
public void setChecked(boolean checked) {
    this.largeLabel.setPivotX((float)(this.largeLabel.getWidth() / 2));
    this.largeLabel.setPivotY((float)this.largeLabel.getBaseline());
    this.smallLabel.setPivotX((float)(this.smallLabel.getWidth() / 2));
    this.smallLabel.setPivotY((float)this.smallLabel.getBaseline());
    switch(this.labelVisibilityMode) {
        case -1:
            if (this.isShifting) {
                if (checked) {
                    this.setViewLayoutParams(this.icon, this.defaultMargin, 49);
                    this.setViewValues(this.largeLabel, 1.0F, 1.0F, 0);
                } else {
                    this.setViewLayoutParams(this.icon, this.defaultMargin, 17);
                    this.setViewValues(this.largeLabel, 0.5F, 0.5F, 4);
                this.smallLabel.setVisibility(4);
            } else if (checked) {
                this.setViewLayoutParams(this.icon, (int)((float)this.defaultMargin + this.shiftAmount), 49);
                this.setViewValues(this.largeLabel, 1.0F, 1.0F, 0);
                this.setViewValues(this.smallLabel, this.scaleUpFactor, this.scaleUpFactor, 4);
            } else {
                this.setViewLayoutParams(this.icon, this.defaultMargin, 49);
                this.setViewValues(this.largeLabel, this.scaleDownFactor, this.scaleDownFactor, 4);
                this.setViewValues(this.smallLabel, 1.0F, 1.0F, 0);
            break;
        case 0:
            if (checked) {
                this.setViewLayoutParams(this.icon, this.defaultMargin, 49);
                this.setViewValues(this.largeLabel, 1.0F, 1.0F, 0);
            } else {
                this.setViewLayoutParams(this.icon, this.defaultMargin, 17);
                this.setViewValues(this.largeLabel, 0.5F, 0.5F, 4);
            this.smallLabel.setVisibility(4);
            break;
        case 1:
            if (checked) {
                this.setViewLayoutParams(this.icon, (int)((float)this.defaultMargin + this.shiftAmount), 49);
                this.setViewValues(this.largeLabel, 1.0F, 1.0F, 0);
                this.setViewValues(this.smallLabel, this.scaleUpFactor, this.scaleUpFactor, 4);
            } else {
                this.setViewLayoutParams(this.icon, this.defaultMargin, 49);
                this.setViewValues(this.largeLabel, this.scaleDownFactor, this.scaleDownFactor, 4);
                this.setViewValues(this.smallLabel, 1.0F, 1.0F, 0);
            break;
        case 2:
            this.setViewLayoutParams(this.icon, this.defaultMargin, 17);
            this.largeLabel.setVisibility(8);
            this.smallLabel.setVisibility(8);
        this.refreshDrawableState();
        this.setSelected(checked);
//...
最终，在新版的 Android Design 中使用 BottomNavigationView 只用在布局文件中添加两个属性就可以达到上图中的效果
app:itemHorizontalTranslationEnabled=”false”
app:labelVisibilityMode=”labeled”
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".activity.MainActivity">
    <com.xxx.xxxxx.view.NoScrollViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
    <android.support.design.widget.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="@color/colorAppBackground"
        app:itemHorizontalTranslationEnabled="false"
        app:itemIconTint="@drawable/main_view"
        app:itemTextColor="@drawable/main_view"
        app:labelVisibilityMode="labeled"
        app:menu="@menu/main_navigation" />
</LinearLayout>
最后，展示一下各个模式下区别
labeled

unlabeled

select

如果item>3效果等同于select
如果item<=3效果等同于labeled
  发布时间:2018年09月27日 - 15:09
  最后更新:2018年11月12日 - 11:11
  原始链接:https://cazaea.com/2018/09/27/BottomNavigationView最新使用/
  许可协议: 署名-非商业性使用-禁止演绎 4.0 国际 转载请保留原文链接及作者。
BottomNavigationView最新用法

☠ But！ 在 com.android.support:design 版本高于 27.0.3 之后，这个方法失效，这也是我接下来着重介绍 方法二 的原因

首先看一下源码

☠ But！在 com.android.support:design 版本高于 27.0.3 之后，这个方法失效，这也是我接下来着重介绍方法二的原因
