compile 'com.android.support:appcompat-v7:23.0.0'

  compile 'com.android.support:design:23.+'

  compile 'com.roughike:bottom-bar:1.3.+'

public class Menu1Activity extends AppCompatActivity {

    private BottomBar mBottomBar;

    private MainFragment mMainFragment;

    private TwoFragment twoFragment;

    private ThreeFragment threeFragment;

    private FourFragment fourFragment;

    private FragmentTransaction transaction;

    private BottomBarBadge unreadMessages;

    @Override

    protected void onCreate(@Nullable Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_menu);

        mBottomBar = BottomBar.attach(this, savedInstanceState);

        // 千万注意：这个方法要用在 setItemsFromMenu 之前，也就是tab还没有设置之前要先调用，不然会报错。

        mBottomBar.noTabletGoodness();

        //添加初始Fragment

        defaultFragment(null == mMainFragment ? mMainFragment = MainFragment.newInstance() : mMainFragment);

        mBottomBar.setItems(R.menu.bottombar_menu);

        mBottomBar.setOnMenuTabClickListener(new OnMenuTabClickListener() {

            @Override

            public void onMenuTabSelected(@IdRes int menuItemId) {

                //单击事件 menuItemId 是 R.menu.bottombar_menu 中 item 的 id

                switch (menuItemId) {

                    case R.id.bb_menu_main:

                        if (null == mMainFragment) {

                            mMainFragment = MainFragment.newInstance();

                        }

                        replaceFragment(mMainFragment);

                        break;

                    case R.id.bb_menu_chart:

                        if (null == twoFragment) {

                            twoFragment = TwoFragment.newInstance();

                        }

                        replaceFragment(twoFragment);

                        unreadMessages.setVisibility(View.GONE);

                        break;

                    case R.id.bb_menu_timeline:

                        if (null == threeFragment) {

                            threeFragment = ThreeFragment.newInstance();

                        }

                        replaceFragment(threeFragment);

                        break;

                    case R.id.bb_menu_about:

                        if (null == fourFragment) {

                            fourFragment = FourFragment.newInstance();

                        }

                        replaceFragment(fourFragment);

                        break;

                    default:

                        break;

                }

            }

            @Override

            public void onMenuTabReSelected(@IdRes int menuItemId) {

                //重选事件，当前已经选择了这个，又点了这个tab。微博点击首页刷新页面

            }

        });

        // 当点击不同按钮的时候，设置不同的颜色

        // 可以用以下三种方式来设置颜色.

        mBottomBar.mapColorForTab(0, ContextCompat.getColor(this, R.color.colorPrimary));

        mBottomBar.mapColorForTab(1, ContextCompat.getColor(this, R.color.colorAccent));

        mBottomBar.mapColorForTab(2, ContextCompat.getColor(this, R.color.green));

        mBottomBar.mapColorForTab(3, ContextCompat.getColor(this, R.color.orange));

        setMsg();

    }

    @Override

    protected void onSaveInstanceState(Bundle outState) {

        super.onSaveInstanceState(outState);

        //保存BottomBar的状态

        mBottomBar.onSaveInstanceState(outState);

    }

    private void replaceFragment(Fragment fragment) {

        FragmentManager fm = getSupportFragmentManager();

        transaction = fm.beginTransaction();

        transaction.replace(R.id.main_fragment_layout, fragment);

//        transaction.hide();

        transaction.commit();

    }

    private void defaultFragment(Fragment fragment) {

        FragmentManager fm = getSupportFragmentManager();

        transaction = fm.beginTransaction();

        transaction.add(R.id.main_fragment_layout, fragment);

        transaction.commit();

    }

    private void setMsg() {

        // 为tab设置一个标签，“信息”提示的数字

        // 参数分别是：第几个tab；小圆圈的颜色；显示的数字

        unreadMessages = mBottomBar.makeBadgeForTabAt(1, "#FF0000", 13);

        // 设置显示或隐藏

        unreadMessages.show();

//        unreadMessages.hide();

        // 设置显示的数字

        unreadMessages.setCount(4);

        // 设置显示/消失动画的延迟时间

        unreadMessages.setAnimationDuration(200);

        // 如果不点它，它一直显示

        unreadMessages.setAutoShowAfterUnSelection(true);

    }