ViewPager + Fragment Fragment內跳轉

viewpager 設置FragmentPagerAdapter。

public class ViewPagerAdapter extends FragmentPagerAdapter {


private BaseFragment mFragmentAtPos0, mFragmentAtPos1; // Fragment at index
// 0
private MyStack stackat0;
private MyStack stackat1;
private final FragmentManager mFragmentManager;


private static final int NUM_OF_ITEMS = 4; // No of ViewPager items


public ViewPagerAdapter(FragmentManager fm) {
super(fm);
mFragmentManager = fm;
stackat0 = new MyStack();
stackat1 = new MyStack();
}


@Override
public Fragment getItem(int position) {
if (position == 0) {
if (mFragmentAtPos0 == null) {
mFragmentAtPos0 = Mainfragment.newInstance();
stackat0.push(mFragmentAtPos0);
}
return mFragmentAtPos0;
} else if (position == 1) {
if (mFragmentAtPos1 == null) {
mFragmentAtPos1 = ArticleListForscFragment.newInstance();
stackat1.push(mFragmentAtPos1);
}
return mFragmentAtPos1;
} else if (position == 2) {
return NSfragment.newInstance();
}
return new Settingfragment();
}


@Override
public int getCount() {
return NUM_OF_ITEMS;
}


@Override
public int getItemPosition(Object object) {

//POSITION_NONE當adapter獲取此值時，得到無次位置的fragment則會自動刷新
if (object instanceof Mainfragment) {
return POSITION_NONE;
} else if (object instanceof ChilditemFragment) {
return POSITION_NONE;
} else if (object instanceof ArticleListFragment) {
return POSITION_NONE;
} else if (object instanceof MsgContentFragment) {
return POSITION_NONE;
} else if (object instanceof NSlanmuFragment) {
return POSITION_NONE;
} else if (object instanceof NStitlefragment) {
return POSITION_NONE;
} else if (object instanceof NScontentfragment) {
return POSITION_NONE;
} else if (object instanceof ArticleListForscFragment) {
return POSITION_NONE;
} else if (object instanceof MsgContentForscFragment) {
return POSITION_NONE;
}
return POSITION_UNCHANGED;
}

//ViewPager內的一個fragment跳轉到另一個fragment
public void AddStackAt0(BaseFragment old, BaseFragment nf) {
stackat0.push(nf);
mFragmentManager.beginTransaction().remove(mFragmentAtPos0).commit();
mFragmentAtPos0 = nf;
notifyDataSetChanged();
}


public void AddStackAt1(BaseFragment old, BaseFragment nf) {
stackat1.push(nf);
mFragmentManager.beginTransaction().remove(mFragmentAtPos1).commit();
mFragmentAtPos1 = nf;
notifyDataSetChanged();
}

//處理fragment的返回
public void RemoveStackAt0() {
mFragmentManager.beginTransaction().remove(mFragmentAtPos0).commit();
stackat0.pop();
if (stackat0.getTop() instanceof Mainfragment) {
mFragmentAtPos0 = Mainfragment.newInstance();
} else if (stackat0.getTop() instanceof ChilditemFragment) {
mFragmentAtPos0 = ChilditemFragment.newInstance();
} else if (stackat0.getTop() instanceof ArticleListFragment) {
mFragmentAtPos0 = ArticleListFragment.newInstance();
} else if (stackat0.getTop() instanceof NSlanmuFragment) {
mFragmentAtPos0 = NSlanmuFragment.newInstance();
} else if (stackat0.getTop() instanceof NStitlefragment) {
mFragmentAtPos0 = NStitlefragment.newInstance();
}
notifyDataSetChanged();
}


public void RemoveStackAt1() {
mFragmentManager.beginTransaction().remove(mFragmentAtPos1).commit();
stackat1.pop();
if (stackat1.getTop() instanceof ArticleListForscFragment) {
mFragmentAtPos1 = ArticleListForscFragment.newInstance();
}
notifyDataSetChanged();
}


public boolean Canback(int index) {
switch (index) {
case 0:
return stackat0.hasNext();


case 1:
return stackat1.hasNext();


}
return false;
}


public void Back(int index) {
switch (index) {
case 0:
RemoveStackAt0();
break;
case 1:
RemoveStackAt1();
break;
default:
break;
}
}


}

其中Stack為棧，保存position0,1,2,3的頁面緩存棧

public class MyStack {
private List<BaseFragment> mylist;
public MyStack()
{
mylist=new ArrayList<BaseFragment>();
}
public void push(BaseFragment push)
{
mylist.add(push);
}
public int getsize(){
return mylist.size();
}
public boolean isempty(){
return mylist.isEmpty();
}
public BaseFragment pop(){
BaseFragment b=mylist.get(mylist.size()-1);
mylist.remove(mylist.size()-1);
System.out.println("after pop size"+mylist.size());
return b;
}
public Boolean hasNext(){
if(mylist.size()>1){
return true;
}
return false;
}
public BaseFragment getTop(){
System.out.println("after gettop size"+mylist.size());
return mylist.get(mylist.size()-1);
}
}

在每一個Fragment當中

@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
LayoutInflater inflater = getActivity().getLayoutInflater();
nscview = inflater.inflate(R.layout.fragment_nscontent,
(ViewGroup) getActivity().findViewById(R.id.main_ViewPager),
false);

//false為重點，必須為false或null

}

public View onCreateView(LayoutInflater inflater,
@Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
// TODO Auto-generated method stub

               /*以下判斷必須，不添加則會產生(28637): java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.異常*/
ViewGroup p = (ViewGroup) nscview.getParent();
if (p != null) {
p.removeAllViewsInLayout();
Log.v("swc", "NScontent-->移除已存在的View");
}
System.out.println("NScontent fragment getview");
return nscview;
}