我有三个ViewPager一个Fragments，每一个示出了List（或Grid）。
在新Android API level 17（果冻豆4.2）的特点之一是Nested Fragments。新功能介绍说：
如果你使用ViewPager创建轻扫左，右和消耗了大部分的屏幕空间的片段，你现在可以插入片段到每个片段页。
所以，如果我理解正确的，现在我可以创建一个ViewPager Fragments（里面例如按钮）内，当用户按下按钮显示另一Fragment无松弛使用这个新功能的ViewPager。
我已经花费了我早上想实现这一几种不同的方式，但我不能得到它的工作...有人可以添加如何实现一个简单的例子？
PS：我只是在这样做有兴趣，有getChildFragmentManager学习如何工作的。
假设你已经创建了正确的XML布局。现在是很简单的由另一个片段主办的ViewPager显示片段。
以下是显示子片段父片段：
class ParentViewPagerFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val root = inflater.inflate(R.layout.fragment_parent_viewpager, container, false)
val viewPager = root.findViewById(R.id.viewPager) as ViewPager
// Important: Must use the child FragmentManager or you will see side effects.
viewPager.adapter = MyAdapter(childFragmentManager)
val tabStrip = root.findViewById<TabLayout>(R.id.pagerTabStrip)
tabStrip.setupWithViewPager(viewPager)
return root
}
class MyAdapter internal constructor(fm: FragmentManager) : FragmentPagerAdapter(fm) {
override fun getCount(): Int = 4
override fun getItem(position: Int): Fragment {
val args = Bundle().apply { putInt(ChildFragment.POSITION_KEY, position) }
return ChildFragment.newInstance(args)
}
override fun getPageTitle(position: Int): CharSequence = "Tab $position"
}
companion object {
val TAG: String = ParentViewPagerFragment::class.java.name
}
}
实例化FragmentPagerAdapter时使用Fragment.getChildFragmentManager（）是非常重要的。另外请注意，你不能对孩子片段使用Fragment.setRetainInstance（），否则你会得到一个异常。在进口量不再赘述。
源代码可以在这里找到：https://github.com/marcoRS/nested-fragments
编辑：如果您想更换页面的所有内容，你仍然可以使用嵌套的片段一ViewPager，但还需要一些改变。检查下面的试样（FragmentActivity，设置ViewPager和PagerAdapter是相同的代码前面的代码段）：
// this will act as a fragment container, representing one page in the ViewPager
public static class WrapperFragment extends Fragment implements
ReplaceListener {
public static WrapperFragment newInstance(int position) {
WrapperFragment wp = new WrapperFragment();
Bundle args = new Bundle();
args.putInt("position", position);
wp.setArguments(args);
return wp;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
FrameLayout fl = new FrameLayout(getActivity());
fl.setId(10000);
if (getChildFragmentManager().findFragmentByTag("initialTag") == null) {
InitialInnerFragment iif = new InitialInnerFragment();
Bundle args = new Bundle();
args.putInt("position", getArguments().getInt("position"));
iif.setArguments(args);
getChildFragmentManager().beginTransaction()
.add(10000, iif, "initialTag").commit();
}
return fl;
}
// required because it seems the getChildFragmentManager only "sees"
// containers in the View of the parent Fragment.
@Override
public void onReplace(Bundle args) {
if (getChildFragmentManager().findFragmentByTag("afterTag") == null) {
InnerFragment iif = new InnerFragment();
iif.setArguments(args);
getChildFragmentManager().beginTransaction()
.replace(10000, iif, "afterTag").addToBackStack(null)
.commit();
}
}
}
// the fragment that would initially be in the wrapper fragment
public static class InitialInnerFragment extends Fragment {
private ReplaceListener mListener;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mListener = (ReplaceListener) this.getParentFragment();
LinearLayout ll = new LinearLayout(getActivity());
Button b = new Button(getActivity());
b.setGravity(Gravity.CENTER_HORIZONTAL);
b.setText("Frame " + getArguments().getInt("position"));
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Bundle args = new Bundle();
args.putInt("positionInner",
getArguments().getInt("position"));
if (mListener != null) {
mListener.onReplace(args);
}
}
});
ll.setOrientation(LinearLayout.VERTICAL);
ll.addView(b, new LinearLayout.LayoutParams(250,
LinearLayout.LayoutParams.WRAP_CONTENT));
return ll;
}
}
public static class InnerFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
TextView tv = new TextView(getActivity());
tv.setText("InnerFragment in the outher Fragment with position "
+ getArguments().getInt("positionInner"));
return tv;
}
}
public interface ReplaceListener {
void onReplace(Bundle args);
}
在快速浏览一下它的工作原理，但我还没有测试它得多，可能会出现的问题。
有人可以显示如何做一个简单的例子？
使用嵌套片段似乎很容易，直到Commonsware配备了更精细的样品，你可以试试下面的代码：
public class NestedFragments extends FragmentActivity {
@Override
protected void onCreate(Bundle arg0) {
super.onCreate(arg0);
ViewPager vp = new ViewPager(this);
vp.setId(5000);
vp.setAdapter(new MyAdapter(getSupportFragmentManager()));
setContentView(vp);
}
private static class MyAdapter extends FragmentPagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return WrapperFragment.newInstance(position);
}
@Override
public int getCount() {
return 8;
}
}
public static class WrapperFragment extends Fragment {
public static WrapperFragment newInstance(int position) {
WrapperFragment wp = new WrapperFragment();
Bundle args = new Bundle();
args.putInt("position", position);
wp.setArguments(args);
return wp;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
LinearLayout ll = new LinearLayout(getActivity());
FrameLayout innerFragContainer = new FrameLayout(getActivity());
innerFragContainer.setId(1111);
Button b = new Button(getActivity());
b.setText("Frame " + getArguments().getInt("position"));
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
InnerFragment innerFragment = new InnerFragment();
Bundle args = new Bundle();
args.putInt("positionInner",
getArguments().getInt("position"));
innerFragment.setArguments(args);
FragmentTransaction transaction = getChildFragmentManager()
.beginTransaction();
transaction.add(1111, innerFragment).commit();
}
});
ll.setOrientation(LinearLayout.VERTICAL);
ll.addView(b, new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT));
ll.addView(innerFragContainer, new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.MATCH_PARENT));
return ll;
}
}
public static class InnerFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
TextView tv = new TextView(getActivity());
tv.setText("InnerFragment in the outher Fragment with position "
+ getArguments().getInt("positionInner"));
return tv;
}
}
}
我是懒惰，取得了代码的一切，但我敢肯定它可以与膨胀XML的布局工作。