前言

底部Tab已经是一个应用的标配了，因为手机屏幕大小的限制，使得我们必须去最大化的利用可见的空间。当然底部Tab一般为3个左右，最多不会超过5个。

效果图

下面是我使用TabLayout来实现的底部Tab，

实现方式也很简单，因为这里没有“小滑块”。只需要去处理，Tab的滑动和点击即可。

代码：

public class CustomBotTabItem {

    private TabLayout mTabLayout;
    private ViewPager mViewPager;
    private Context mContext;
    //底部Tab标题
    private final String[] mTitles = {"主页", "理财", "添加", "消息", "我的"};
    //返回CustomBotTabItem实例
    public static CustomBotTabItem create() {
        return TabItemHolder.sCustomTabItem;
    }
    //创建CustomBotTabItem实例
    private static class TabItemHolder {
        private static CustomBotTabItem sCustomTabItem = new CustomBotTabItem();
    }
    //引入布局需要的Context
    public CustomBotTabItem setContext(Context context) {
        mContext = context;
        return this;
    }
    //需要自定义的TabLayout
    public CustomBotTabItem setTabLayout(TabLayout tabLayout) {
        mTabLayout = tabLayout;
        return this;
    }
    //设置与TabLayout关联的ViewPager
    public CustomBotTabItem setViewPager(ViewPager viewPager) {
        mViewPager = viewPager;
        return this;
    }
    //创建Tab
    public CustomBotTabItem build() {
        initTabLayout();
        return this;
    }
    //初始化Tab
    private void initTabLayout() {
        mTabLayout.setupWithViewPager(mViewPager);
        //第二个参数为selector，下同
        mTabLayout.getTabAt(0).setCustomView(getTabView(0, R.drawable.home_icon_selector));
        mTabLayout.getTabAt(1).setCustomView(getTabView(1, R.drawable.manage_icon_selector));
        mTabLayout.getTabAt(2).setCustomView(getTabView(2, R.drawable.add_icon_selector));
        mTabLayout.getTabAt(3).setCustomView(getTabView(3, R.drawable.find_icon_selector));
        mTabLayout.getTabAt(4).setCustomView(getTabView(4, R.drawable.money_icon_selector));
        tabSelectListener();
    }
     //自定义Tab样式
    private View getTabView(final int position, int resId) {
        final View view = LayoutInflater.from(mContext).inflate(R.layout.bottom_tab_item, null);
        TextView tvTitle = (TextView) view.findViewById(R.id.id_tv_title);
        final ImageView ivTitle = (ImageView) view.findViewById(R.id.id_iv_title);
        ivTitle.setImageResource(resId);
        tvTitle.setText(mTitles[position]);
        //默认第一个tab选中，设置字体为选中色
        if (position == 0) {
            tvTitle.setTextColor(Color.parseColor("#4192e3"));
        } else {
            tvTitle.setTextColor(Color.parseColor("#262a3b"));
        }
        //点击Tab切换
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mViewPager.setCurrentItem(position);
            }
        });
        return view;
    }
    //Tab监听
    private void tabSelectListener() {
        mTabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                changeTabStatus(tab, true);
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {
                changeTabStatus(tab, false);
            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
    }
    //切换Tab文字是否选中的的颜色
    private void changeTabStatus(TabLayout.Tab tab, boolean selected) {
        View view = tab.getCustomView();
        if (view == null) {
            return;
        }
        TextView tvTitle = (TextView) view.findViewById(R.id.id_tv_title);
        if (selected) {
            tvTitle.setTextColor(Color.parseColor("#4192e3"));
        } else {
            tvTitle.setTextColor(Color.parseColor("#262a3b"));
        }
    }
}

Activity 代码：

public class BottomTabLayoutActivity extends AppCompatActivity {

    private TabLayout mTabLayout;
    private ViewPager mViewPager;
    private List<Fragment> mFragmentList;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bot_tab_layout);
        findView();
        initFragmentList();
        setVpAdapter();
        CustomBotTabItem item = CustomBotTabItem.create();
        item.setContext(this)
                .setViewPager(mViewPager)
                .setTabLayout(mTabLayout)
                .build();
    }
    //findViewById
    private void findView() {
        mTabLayout = (TabLayout) findViewById(R.id.id_tab_layout);
        mViewPager = (ViewPager) findViewById(R.id.id_vp);
    }
    //初始化需要的Fragment
    private void initFragmentList() {
        mFragmentList = new ArrayList<>();
        mFragmentList.add(TabFragment.getInstance("主页"));
        mFragmentList.add(TabFragment.getInstance("理财"));
        mFragmentList.add(TabFragment.getInstance("添加"));
        mFragmentList.add(TabFragment.getInstance("消息"));
        mFragmentList.add(TabFragment.getInstance("我的"));
    }
    //设置ViewPager的Adapter
    private void setVpAdapter() {
        mViewPager.setAdapter(new FragmentAdapter(getSupportFragmentManager(), mFragmentList, this));
    }
}

Activity.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                xmlns:app="http://schemas.android.com/apk/res-auto"
                android:layout_width="match_parent"
                android:layout_height="match_parent">

    <android.support.design.widget.TabLayout
        android:id="@+id/id_tab_layout"
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:layout_alignParentBottom="true"
        android:background="#fff"
        android:fillViewport="false"
        app:layout_scrollFlags="scroll"
        app:tabIndicatorHeight="0dp"
        app:tabMode="fixed"
        >
    </android.support.design.widget.TabLayout>

    <android.support.v4.view.ViewPager
        android:id="@+id/id_vp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/id_tab_layout"
        />
</RelativeLayout>

好了，具体思路、代码就这么多了，其它需要的文件都比较简单，自己添加一下吧。