（二）用TabLayout搭建首屏界面

学生时代DOTA的年代，Android上是有一个App的，后来作者就没更新了。那个年代就有用Tab的了，非常方便快捷，食堂吃饭的时候能拿出来滑两下看看，到宿舍就实践起来^_。所以就决定了，用Tab

走的弯路

一开始是在github找的第三方开源库SmartLayout 围观地址
严格意义上来说并不是弯路，是因为 我不会啊！技术不到家不会用啊！我表示很无奈啊！
怼来怼去半天，发现了TabLayout这个东西，是Google官方的东西，资料比较多一点，所以选择了这个，其实按我的审美，还是SmartLayout好看啊T T

开始撸代码咯

1. 添加依赖

TabLayout是Android Support Design里面的新东西，需要在Android Studio的SDK Manager——SDK Tools中勾选Android Support Library下载，截止到今天2016.3.14，最新版本为23.2.1，接下来还要在Project工程文件下的build.gradle中的dependency中添加一行代码compile 'com.android.support:design:23.2.1'

2.正式开始写代码

首先需要创建一个布局，直接修改activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">
    <android.support.design.widget.TabLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tabs"/>
    <android.support.v4.view.ViewPager
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/viewpager"
        android:layout_below="@id/tabs"/>
</RelativeLayout>```
接下来创建一个PageFragment.java
```Java 
package com.noisay.dota2guide.fragment;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.noisay.dota2guide.R;


public class PageFragment extends Fragment {
    public static final String ARG_PAGE = "ARG_PAGE";
    private int mPage;//此变量纯粹用来做Fragment内容的展示编号，后期会删除

    public static PageFragment newInstance(int page) {
        Bundle args = new Bundle();
        args.putInt(ARG_PAGE, page);
        PageFragment pageFragment = new PageFragment();
        pageFragment.setArguments(args);
        return pageFragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mPage = getArguments().getInt(ARG_PAGE);
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_page, container, false);
        TextView textView = (TextView) view;
        textView.setText("Fragment #" + mPage);
        return view;
    }
}```
然后新建一个fragment_page.xml，代码如下
```Java
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center" />

再新建一个SimpleFragmentPagerAdapter.java来适配

package com.noisay.dota2guide.adapter;

import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

import com.noisay.dota2guide.fragment.PageFragment;

/**
 * Created by noisa on 2016/3/14.
 */
public class SimpleFragmentPagerAdapter extends FragmentPagerAdapter{
    final int PAGE_COUNT = 4;
    private String tabTitles[] = new String[]{"敏捷英雄", "智力英雄", "力量英雄", "装备"};
    private Context context;

    public SimpleFragmentPagerAdapter(FragmentManager fm, Context context) {
        super(fm);
        this.context = context;
    }

    @Override
    public Fragment getItem(int position) {
        return PageFragment.newInstance(position+1);//加1是因为position是从0开始
    }

    @Override
    public int getCount() {
        return PAGE_COUNT;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return tabTitles[position];
    }
}

最后一步，修改MainActivity.java

package com.noisay.dota2guide;

import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;

import com.noisay.dota2guide.adapter.SimpleFragmentPagerAdapter;

/**
 * Created by noisa on 2016/3/14.
 */
public class MainActivity extends FragmentActivity {
    private SimpleFragmentPagerAdapter pagerAdapter;

    private ViewPager viewPager;

    private TabLayout tabLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pagerAdapter = new SimpleFragmentPagerAdapter(getSupportFragmentManager(), this);
        viewPager = (ViewPager) findViewById(R.id.viewpager);
        viewPager.setAdapter(pagerAdapter);
        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);
        tabLayout.setTabMode(TabLayout.MODE_FIXED);
    }
}

最终呈现出来的效果，没有真机录不了视频转Gif，简直血崩一波。。。。。看个PNG凑合一下吧

捕获.PNG

本人现在还是超级菜鸟一枚，此文中部分代码来自于Chenfuduo的《TabLayout of design support library 》一问，结合App的需要有做修改，原文链接