Android中ViewPager和Fragment的使用

<android.support.v4.view.viewpager
  android:id="@+id/viewpager"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
</android.support.v4.view.viewpager>

 fragments = new arraylist<>();
 conversationfragment fragment1 = new conversationfragment();
 groupfragment fragment2 = new groupfragment();
 searchfragment fragment3 = new searchfragment();
 fragments.add(fragment1);
 fragments.add(fragment2);
 fragments.add(fragment3);
 adapter = new mainpageradapter(getsupportfragmentmanager(), fragments);
 viewpager.setadapter(adapter);

public class mainpageradapter extends fragmentpageradapter{

  list<fragment> fragmentlist;

  public mainpageradapter(fragmentmanager fm, list<fragment> fragmentlist) {
    super(fm);
    this.fragmentlist = fragmentlist;
  }

  @override
  public fragment getitem(int position) {
    return fragmentlist.get(position);
  }

  @override
  public int getcount() {
    return fragmentlist.size();
  }
}

viewpager.addonpagechangelistener(new viewpager.onpagechangelistener() {
  @override
  public void onpagescrolled(int position, float positionoffset, int positionoffsetpixels) {
    int distance = positionoffsetpixels / 3;
    //一旦fragment滑动，这里的position实际是前一个的
    viewpropertyanimator.animate(v_indicate_line).translationx(distance + position * v_indicate_line.getwidth()).setduration(0);
  }

  @override
  public void onpageselected(int position) {
    textlightandsize();
  }


  @override
  public void onpagescrollstatechanged(int state) {

  }
});

//这里是注意setcurrentitem的用法
switch (view.getid()) {
  case r.id.ly_conversation:
    viewpager.setcurrentitem(0);
    break;
  case r.id.ly_group:
    viewpager.setcurrentitem(1);
    break;
  case r.id.ly_search:
    viewpager.setcurrentitem(2);
    break;
}

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:padding="4dip"
    android:gravity="center_horizontal"
    android:layout_width="match_parent" android:layout_height="match_parent">

  <android.support.v4.view.viewpager
      android:id="@+id/pager"
      android:layout_width="match_parent"
      android:layout_height="0px"
      android:layout_weight="1">
  </android.support.v4.view.viewpager>

  <linearlayout android:orientation="horizontal"
      android:gravity="center" android:measurewithlargestchild="true"
      android:layout_width="match_parent" android:layout_height="wrap_content"
      android:layout_weight="0">
    <button android:id="@+id/goto_first"
      android:layout_width="wrap_content" android:layout_height="wrap_content"
      android:text="@string/first">
    </button>
    <button android:id="@+id/goto_last"
      android:layout_width="wrap_content" android:layout_height="wrap_content"
      android:text="@string/last">
    </button>
  </linearlayout>
</linearlayout>

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="@android:drawable/gallery_thumb">

  <textview android:id="@+id/text"
    android:layout_width="match_parent" android:layout_height="wrap_content"
    android:gravity="center_vertical|center_horizontal"
    android:textappearance="?android:attr/textappearancemedium"
    android:text="@string/hello_world"/>

  <!-- the frame layout is here since we will be showing either
  the empty view or the list view. -->
  <framelayout
    android:layout_width="match_parent"
    android:layout_height="0dip"
    android:layout_weight="1" >
    <!-- here is the list. since we are using a listactivity, we
       have to call it "@android:id/list" so listactivity will
       find it -->
    <listview android:id="@android:id/list"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:drawselectorontop="false"/>

    <!-- here is the view to show if the list is emtpy -->
    <textview android:id="@android:id/empty"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:textappearance="?android:attr/textappearancemedium"
      android:text="no items."/>

  </framelayout>

</linearlayout>

public class fragmentpagersupport extends fragmentactivity {
  static final int num_items = 10;

  myadapter madapter;

  viewpager mpager;

  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.fragment_pager);

    madapter = new myadapter(getsupportfragmentmanager());

    mpager = (viewpager)findviewbyid(r.id.pager);
    mpager.setadapter(madapter);

    // watch for button clicks.
    button button = (button)findviewbyid(r.id.goto_first);
    button.setonclicklistener(new onclicklistener() {
      public void onclick(view v) {
        mpager.setcurrentitem(0);
      }
    });
    button = (button)findviewbyid(r.id.goto_last);
    button.setonclicklistener(new onclicklistener() {
      public void onclick(view v) {
        mpager.setcurrentitem(num_items-1);
      }
    });
  }

  public static class myadapter extends fragmentpageradapter {
    public myadapter(fragmentmanager fm) {
      super(fm);
    }

    @override
    public int getcount() {
      return num_items;
    }

    @override
    public fragment getitem(int position) {
      return arraylistfragment.newinstance(position);
    }
  }

  public static class arraylistfragment extends listfragment {
    int mnum;

    /**
     * create a new instance of countingfragment, providing "num"
     * as an argument.
     */
    static arraylistfragment newinstance(int num) {
      arraylistfragment f = new arraylistfragment();

      // supply num input as an argument.
      bundle args = new bundle();
      args.putint("num", num);
      f.setarguments(args);

      return f;
    }

    /**
     * when creating, retrieve this instance's number from its arguments.
     */
    @override
    public void oncreate(bundle savedinstancestate) {
      super.oncreate(savedinstancestate);
      mnum = getarguments() != null ? getarguments().getint("num") : 1;
    }

    /**
     * the fragment's ui is just a simple text view showing its
     * instance number.
     */
    @override
    public view oncreateview(layoutinflater inflater, viewgroup container,
        bundle savedinstancestate) {
      view v = inflater.inflate(r.layout.fragment_pager_list, container, false);
      view tv = v.findviewbyid(r.id.text);
      ((textview)tv).settext("fragment #" + mnum);
      return v;
    }

    @override
    public void onactivitycreated(bundle savedinstancestate) {
      super.onactivitycreated(savedinstancestate);
      setlistadapter(new arrayadapter<string>(getactivity(),
          android.r.layout.simple_list_item_1, cheeses.scheesestrings));
    }

    @override
    public void onlistitemclick(listview l, view v, int position, long id) {
      log.i("fragmentlist", "item clicked: " + id);
    }
  }
}