SectionsPageAdapter with FragmentPageAdapter

Question

首先讓我試着重現我的問題/問題。

我的活動是帶有3個選項卡的TabbedActivity，使用SectionPageAdapter和FragmentPageAdapter完成。

在這3個選項卡上，用戶輸入數據。只需滑動，用戶可以更改選項卡。在用戶填寫完所有數據後，他必須點擊一個FloatingActionButton來保存數據。

現在有我的問題我不知道如果我可以訪問這些3填充數據的片段？ 我是否可以加載所有3個碎片以填充數據，讀取數據並保存它，或者在更改頁面之前是否必須處理PageChangeListenEvent並保存數據？

代碼：

public class SectionsPagerAdapter extends FragmentPagerAdapter { 

    public SectionsPagerAdapter(FragmentManager fm) { 
     super(fm); 
    } 

    @Override 
    public Fragment getItem(int position) { 

     return TravelInfoActivity.PlaceholderFragment.newInstance(position + 1); 
    } 

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

} 


public static class PlaceholderFragment extends Fragment { 

    private static final String ARG_FRAGMENT_ID = "fragment_id"; 
    private static int REQUEST_CODE_PLACE = 1; 
    private View currentRootView; 
    private View currentClickedView; 

    @SuppressLint("UseSparseArrays") 
    private HashMap<Integer, View> hMap = new HashMap<>(); 


    public PlaceholderFragment() { 
    } 

    /** 
    * Returns a new instance of this fragment for the given section 
    * number. 
    */ 
    public static TravelInfoActivity.PlaceholderFragment newInstance(int sectionNumber) { 
     TravelInfoActivity.PlaceholderFragment fragment = new PlaceholderFragment(); 
     Bundle args = new Bundle(); 
     int fragmentLayout; 
     switch (sectionNumber) { 
      case 1: 
       fragmentLayout = R.layout.fragment_accommodation; 
       break; 
      case 2: 
       fragmentLayout = R.layout.fragment_visited_places; 
       break; 
      case 3: 
       fragmentLayout = R.layout.fragment_additional_info; 
       break; 
      default: 
       fragmentLayout = R.layout.fragment_accommodation; 
     } 
     args.putInt(ARG_FRAGMENT_ID, fragmentLayout); 
     fragment.setArguments(args); 
     return fragment; 
    } 
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
     final View rootView = inflater.inflate(getArguments().getInt(ARG_FRAGMENT_ID), container, false); 
     currentRootView = rootView; 
     switch (getArguments().getInt(ARG_FRAGMENT_ID)) { 
      // switch handling here, not relevant 
     } 
return rootView; 
    } 

Answer 1

傢伙，我已經做了刷新我的大腦;）

單從片段實例保存到一個數組，你以後可以使用它。 我在SectionPageAdapter中創建了這個方法，並且使用了方法instantiateItem()。

public class SectionsPagerAdapter extends FragmentStatePagerAdapter { 

    private SparseArray<Fragment> registeredFragments = new SparseArray<>(); 

    public SectionsPagerAdapter(FragmentManager fm) { 
     super(fm); 
    } 


    @Override 
    public Object instantiateItem(ViewGroup container, int position) { 
     Fragment fragment = (Fragment) super.instantiateItem(container, position); 
     Integer fragmentId = fragment.getArguments().getInt("fragment_id"); 
     registeredFragments.put(fragmentToPageMap.get(fragmentId), fragment); 

     return fragment; 
    } 

    public Fragment getRegisteredFragment(int position) { 
     return registeredFragments.get(position); 
    } 

    public boolean registeredFragmentExists(int position) { 
     if(registeredFragments.size() >= position) { 
      if(registeredFragments.get(position) != null) { 
       return true; 
      } 
     } 
     return false; 
    } 


    @Override 
    public Fragment getItem(int position) { 
     // getItem is called to instantiate the fragment for the given page. 
     // Return a PlaceholderFragment (defined as a static inner class below). 
     return TravelInfoActivity.PlaceholderFragment.newInstance(position); 
    } 

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

} 

稍後，您可以用

mSectionsPagerAdapter.getRegisteredFragment(position); 
fragment.getActivity().findViewById(id); 

訪問片段rootView