本文主要介绍如何利用ViewPager、Fragment、PagerTabStrip实现多页面滑动效果。即google play首页、新浪微博消息(at、评论、私信、广播)页面的效果。ViewPager+Fragment组合为google推荐方式,比TabActivity+Activity的效率高的多。
这个效果相当好!
1、新建ViewPager的layout,内容如下
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="match_parent"
- android:layout_height="match_parent"
- android:orientation="vertical" >
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- <android.support.v4.view.ViewPager
- android:id="@+id/viewPager"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center" >
- <android.support.v4.view.PagerTabStrip
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="top" />
- </android.support.v4.view.ViewPager>
- </LinearLayout>
ViewPager用来管理layout并可以左右滑动显示各个页面数据,PagerTabStrip用来显示页面title,android:layout_gravity="top"表示title在顶部,可设置bottom等。
2、新建FragmentActivity页面
FragmentActivity页面含有ViewPager元素,可以用来显示Fragment,定义如下:
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FragmentActivity页面
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public class ViewPagerDemo extends FragmentActivity {
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List<Fragment> fragmentList = new ArrayList<Fragment>();
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List<String> titleList = new ArrayList<String>();
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@Override
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protected void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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setContentView(R.layout.view_pager_demo);
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ViewPager vp = (ViewPager)findViewById(R.id.viewPager);
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fragmentList.add(new ViewPagerFragment1("页面1"));
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fragmentList.add(new ViewPagerFragment1("页面2"));
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fragmentList.add(new ViewPagerFragment1("页面3"));
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titleList.add("title 1 ");
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titleList.add("title 2 ");
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titleList.add("title 3 ");
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vp.setAdapter(new myPagerAdapter(getSupportFragmentManager(), fragmentList, titleList));
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}
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class myPagerAdapter extends FragmentPagerAdapter {
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private List<Fragment> fragmentList;
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private List<String> titleList;
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public myPagerAdapter(FragmentManager fm, List<Fragment> fragmentList, List<String> titleList){
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super(fm);
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this.fragmentList = fragmentList;
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this.titleList = titleList;
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}
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@Override
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public Fragment getItem(int arg0) {
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return (fragmentList == null || fragmentList.size() == 0) ? null : fragmentList.get(arg0);
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}
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@Override
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public CharSequence getPageTitle(int position) {
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return (titleList.size() > position) ? titleList.get(position) : "";
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}
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@Override
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public int getCount() {
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return fragmentList == null ? 0 : fragmentList.size();
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}
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}
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}
其中的myPagerAdapter集成自ragmentPagerAdapter,为ViewPager提供数据源。
onCreate函数得到ViewPager实例并设置数据源,getSupportFragmentManager表示得到Fragment管理器。ViewPagerFragment1表示具体的页面,见下面介绍。
3、新建Fragment页面
Fragment页面即为左右滑动需要显示的页面,新建类集成Fragment,并重写onCreateView函数即可。onCreateView函数相当于Activity的onCreate函数。如下:
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public class ViewPagerFragment1 extends Fragment {
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private String text;
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private TextView tv = null;
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public ViewPagerFragment1(String text){
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super();
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this.text = text;
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}
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@Override
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public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
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View v = inflater.inflate(R.layout.view_pager_fragment_demo1, container, false);
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tv = (TextView)v.findViewById(R.id.viewPagerText);
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tv.setText(text);
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return v;
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}
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}
简单效果如下: