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);    }  }}