Android中ViewPager和Fragment的使用

小案例

XML中

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

创建Fragment

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);

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();
}
}

OnPageChangeListener

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) {
}
});

配合其他点击事件

//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;
}

官方案例

R.layout.fragment_pager

<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>

R.layout.fragment_pager_list

<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);
}
}
}

注意

3.0之前的Activity是不能用fragment的。为了能使用fragment(supportV4中)，才有了FragmentActivity。FragmentActivity继承的Activity。

以上就是本文的全部内容，希望对大家学习Android软件编程有所帮助。

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