#第一章：项目的准备
##一、项目的第一步
导入包

       compile 'com.android.support:design:24.2.1'

软件包分类:

       com.yijia.com.smartbutler.adapter
       com.yijia.com.smartbutler.application
       com.yijia.com.smartbutler.entity
       com.yijia.com.smartbutler.fragment
       com.yijia.com.smartbutler.service
       com.yijia.com.smartbutler.ui
       com.yijia.com.smartbutler.utils
       com.yijia.com.smartbutler.view
##二、主布局
    <?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">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <android.support.design.widget.TabLayout
            android:id="@+id/mTabLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            app:tabGravity="fill"
            app:tabIndicatorColor="@color/colorAccent"
            app:tabMode="fixed"
            app:tabSelectedTextColor="@color/colorAccent"
            app:tabTextColor="@android:color/white" />

        <android.support.v4.view.ViewPager
            android:id="@+id/mViewPager"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1" />

    </LinearLayout>
    //悬浮按钮
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_setting"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_marginBottom="15dp"
        android:layout_marginRight="15dp"
        android:src="@drawable/icon_setting" />

     </RelativeLayout>
##三、BaseActivity——Activity的基类
             显示返回键:
             getSupportActionBar().setDisplayHomeAsUpEnabled(true);


           //菜单栏操作
         @Override
         public boolean onOptionsItemSelected(MenuItem item) {
         switch (item.getItemId()){
            case android.R.id.home://系统自带的返回键点击退出程序
                finish();
                break;
        }
        return super.onOptionsItemSelected(item);
    }
##四、MainActivity
###①初始化数据initData:添加标题和Fragment
    //初始化数据
    private void initData() {
        mTiltle = new ArrayList<String>();
        mTiltle.add("服务管家");
        mTiltle.add("微信精选");
        mTiltle.add("美女社区");
        mTiltle.add("个人中心");

        mFragment = new ArrayList<Fragment>();
        mFragment.add(new BulterFragment());
        mFragment.add(new WeChatFragment());
        mFragment.add(new GirlFragment());
        mFragment.add(new UserFragment());
    }
###②初始化initView:
 //初始化view
    private void initView() {
        mTabLayout = (TabLayout) findViewById(R.id.mTabLayout);
        mViewPager = (ViewPager) findViewById(R.id.mViewPager);

        //预加载
        mViewPager.setOffscreenPageLimit(mFragment.size());
    
        //设置适配器
        mViewPager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
            //选中的
            @Override
            public Fragment getItem(int position) {
                return mFragment.get(position);
            }

            //返回item的个数
            @Override
            public int getCount() {
                return mFragment.size();
            }

            //返回标题
            @Override
            public CharSequence getPageTitle(int position) {
                return mTiltle.get(position);
            }
        });
        mTabLayout.setupWithViewPager(mViewPager);
    }
###③隐藏悬浮按钮
      mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                if (position == 0) {
                    fab_setting.setVisibility(View.GONE);
                } else {
                    fab_setting.setVisibility(View.VISIBLE);
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });