第16天ViewPager案例3：ViewPager+Fragment+TabLayout新闻头部标题导航（*****）

ViewPager

一.效果

二.思路：1个ViewPager+5个Fragment+1个FragmentPagerAdapter+TabLayout

1.容器：ViewPager
2.数据：ArrayList<Fragment ArrayList<String 标题
3.适配器：FragmentViewPager
4.TabLayout：需要导入依赖

重写的方法：
（1）getCount()：返回数据源的总数量
（2）getItem():
（3）getPageTitle():返回标题

三.代码

（1）导入依赖：implementation ‘com.android.support:appcompat-v7:28.0.0’
（2）布局activity_main.xml:ViewPager+TabLayout

<?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"
    tools:context=".MainActivity"
    android:orientation="vertical">
    <!--tabLayout依赖-->
    <android.support.design.widget.TabLayout
        app:tabSelectedTextColor="#E5AF35"
        app:tabTextColor="#969696"
        app:tabIndicatorColor="#E5AF35"
        app:tabIndicatorHeight="5dp"
        app:tabMode="scrollable"
        android:id="@+id/tb"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">
    </android.support.design.widget.TabLayout>
    <android.support.v4.view.ViewPager
        android:id="@+id/vp"
        android:layout_weight="8"
        android:layout_height="0dp"
        android:layout_width="match_parent">

    </android.support.v4.view.ViewPager>
</LinearLayout>

(3)Java代码：MainActivity.java

public class MainActivity extends AppCompatActivity {
    //视图
    private ViewPager vp;
    private TabLayout tb;
    //数据
    private ArrayList<Fragment> fragment_list=new ArrayList<>();
    private ArrayList<String> title_list=new ArrayList<>();//标题
    //适配器
    private MyFragmentPagerAdapter myFragmentPagerAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        initview();
        initdata();
        initadpater();
        //TODO tablayout和viewpager联系在一起
        tb.setupWithViewPager(vp);
    }
    
    private void initadpater() {
        myFragmentPagerAdapter=new MyFragmentPagerAdapter(getSupportFragmentManager(),fragment_list,title_list);
        vp.setAdapter(myFragmentPagerAdapter);
    }

    private void initdata() {
        fragment_list.add(new Fragment1());
        fragment_list.add(new Fragment2());
        fragment_list.add(new Fragment3());
        fragment_list.add(new Fragment4());
        title_list.add("我的");
        title_list.add("新闻");
        title_list.add("最热");
        title_list.add("最强");
    }

    private void initview() {
        vp=findViewById(R.id.vp);
        tb=findViewById(R.id.tb);

    }
}

（4）适配器代码：MyFragmentPagerAdapter.java

public class MyFragmentPagerAdapter extends FragmentPagerAdapter {
    private ArrayList<Fragment> fragment_list;
    private ArrayList<String> title_list;

    public MyFragmentPagerAdapter(FragmentManager fm, ArrayList<Fragment> fragment_list,ArrayList<String> titile_list) {
        super(fm);
        this.fragment_list=fragment_list;
        this.title_list=titile_list;
    }
    @Override
    public Fragment getItem(int i) {
        return fragment_list.get(i);
    }
    @Override
    public int getCount() {
        return fragment_list.size();
    }
    //TODO 返回对应的标题
    @Nullable
    @Override
    public CharSequence getPageTitle(int position) {
        return title_list.get(position);
    }
}

源代码：