Viewpager+fragment

Viewpager+fragment的使用

Fragment嵌套在ViewPager 对应的两个adapter

• FragmentStatePagerAdapter
• FragmentPagerAdapter

FragmentStatePagerAdapter

适用于相对静态,数据量较少的网页,所有生成的fragment都会保存在内存中 ,因此对于数据量较大的应用来说,不太适用,易导致OOM

FramgnetPagerAdapter

只会保存视线中的Framgent 也就是当前显示的Fragment其余的Framgent会被销毁释放内存,不会占用系统更多的内存.

针对他们的优缺点(反正我就要用第二个…)对于我需求更准确的是FramgnetPagerAdapter

首先是FragmentPagerAdapter的实现类:

public class FragAdapter extends FragmentStatePagerAdapter {    private ArrayList<BaseFragment> fragList;    public FragAdapter(FragmentManager fm, ArrayList<BaseFragment> fragList) {        super(fm);        this.fragList=fragList;    }    @Override    public Fragment getItem(int position) {        return fragList.get(position);    }    @Override    public int getCount() {        return fragList.size();    }}

然后创建对应的Fragment ,这里我们就创建空的Fragment背景是不同颜色的用于区分即可.

public class MyFragment extends Fragment {    public MyFragment() {        // Required empty public constructor    }    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);    }    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,                             Bundle savedInstanceState) {        // Inflate the layout for this fragment        return inflater.inflate(R.layout.fragment_my, container, false);    }}

这里没什么可说的,背景颜色自己设置一下用于区分即可.

MainActivity的布局:

<?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"    tools:context="com.example.myapplication.MainActivity">    <android.support.v4.view.ViewPager        android:layout_width="match_parent"        android:layout_height="match_parent"        android:id="@+id/viewPager"    ></android.support.v4.view.ViewPager></RelativeLayout>

MainActivity的代码:

public class MainActivity extends AppCompatActivity {    private ArrayList<Fragment> list;    private MyFragAdapter adapter;    private ViewPager pager;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        list=new ArrayList<Fragment>();        MyFragment fragment1=new MyFragment();        MyFragment fragment2=new MyFragment();        MyFragment fragment3=new MyFragment();        list.add(fragment1);        list.add(fragment2);        list.add(fragment3);        adapter=new MyFragAdapter(getSupportFragmentManager(),list);        pager= (ViewPager) findViewById(R.id.viewPager);        pager.setAdapter(adapter);    }}

颜色我没有设置 偷个懒 运行都没运行 小DEMO