在 ViewPager 的多个选项卡中使用单个片段 [英] Use Single Fragment in Multiple tabs of ViewPager

问题描述

我正在使用ViewPager左右滑动，我也添加了选项卡，选项卡的数量取决于服务器数据，所以我不能将选项卡的数量设为固定.为此，我仅使用 Single Fragment 和 RecyclerView 在 recyclerView 中显示 JSON 数据.当第一个应用程序启动时，应该在第二个选项卡中显示的数据将显示在第一个选项卡本身中.在我滑动到 3rd Tab 并再次返回到 1st Tab 后，数据显示正确.

I am using ViewPager to slide left and right, I have also added the tabs, The number of tabs is depends on the server data, So, I cannot make the number of tabs as Fixed. To do this I used only Single Fragment and a RecyclerView to display JSON Data in the recyclerView. When First app launches, the data which should be shown in 2nd tab is getting displayed in 1st Tab itself. After I swipe to 3rd Tab and come Back again to 1st Tab, then the data is displaying correctly.

与 GooglePlayStore 相同.我认为只有一个片段，因为所有选项卡中的 UI 都是相同的.

It is as same as GooglePlayStore. I think there is only one fragment, because the UI is same in all the tabs.

这是添加 Fragment 并将数据显示到 recyclerView 的代码.

Here is the code to Add Fragment and displaying data to recyclerView.

PagerAdapter.java

PagerAdapter.java

    private class PagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;
    List<List<ProductInfo>> data;



    public PagerAdapter(FragmentManager fm, int NumofTabs, List<List<ProductInfo>> data) {
        super(fm);
        mNumOfTabs = NumofTabs;
        this.data = data;
    }

    @Override
    public Fragment getItem(int position) {
       /* ProductFragment pf = ProductFragment.newInstance(data.get(position),position);
        return pf;*/

        return ProductFragment.newInstance(data.get(position),0);
    }



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

片段.java

public class ProductFragment extends Fragment {
   private static final String ARG_PRODUCTS = "PRODS";
   private static List<ProductInfo> allProducts;
   int position = 0;
   RecyclerView prodList;


public static ProductFragment newInstance(List<ProductInfo> products,int position) {        
    ProductFragment fragment = new ProductFragment();
    Bundle args = new Bundle();
    args.putParcelableArrayList(ARG_PRODUCTS, (ArrayList<ProductInfo>) products);
    args.putInt("KEY_POSITION",position);
    args.putInt("KEY_ID",id);
    fragment.setArguments(args);
    return fragment;
}

 @Override
 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //if(isVisibleToUser){
        if (getArguments() != null) {
            allProducts = getArguments().getParcelableArrayList(ARG_PRODUCTS);
            this.position = getArguments().getInt("KEY_POSITION");
        }
   // }
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_product, container, false);
    prodList = (RecyclerView) view.findViewById(R.id.product_list);
    return view;
}



 @Override
 public void onViewCreated(View view, Bundle savedInstanceState) {

    prodList.setLayoutManager(new LinearLayoutManager(getActivity()));
    prodList.setAdapter(new ProductAdapter(getActivity(), allProducts));
    Log.e("ProductFragment " ,"" + allProducts.get(position).getName());
}

Activity.java

EDITED: Activity.java

onCreate(){
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
    allProducts = new ArrayList<>();

    for (Category cat : catList) {
        tabLayout.addTab(tabLayout.newTab().setText(cat.getName()));
        tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);
        //tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
        allProducts.add(cat.getProductsList());
    }
 viewPager = (ViewPager) findViewById(R.id.pager);
    adapter = new PagerAdapter
            (getSupportFragmentManager(), tabLayout.getTabCount(), allProducts);
    viewPager.setOffscreenPageLimit(0);
    viewPager.setAdapter(adapter);

    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
    tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            Log.e("ViewPager "," getCurrentItem() "+viewPager.getCurrentItem());
            viewPager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });

 }

在此处输入图片说明

推荐答案

在PagerAdapter编辑如下，可能会有帮助:

In PagerAdapter edit as below, it might help:

@Override
public Fragment getItem(int position) {
   /* ProductFragment pf = ProductFragment.newInstance(data.get(position),position);
    return pf;*/

    return ProductFragment.newInstance(data.get(position),position);
}

并在您的 Fragment 中进行如下更改:

And in your Fragment make changes as below:

public class ProductFragment extends Fragment {
private static final String ARG_PRODUCTS = "PRODS";
private static List<ProductInfo> allProducts;
int position = 0;
RecyclerView prodList;
ProductAdapter productAdapter=null;


public static ProductFragment newInstance(List<ProductInfo> products,int position) {        
ProductFragment fragment = new ProductFragment();
Bundle args = new Bundle();
args.putParcelableArrayList(ARG_PRODUCTS, (ArrayList<ProductInfo>) products);
args.putInt("KEY_POSITION",position);
args.putInt("KEY_ID",id);
fragment.setArguments(args);
return fragment;
}

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);
  if(isVisibleToUser){
      productAdapter.notifyDataSetChanged();
    }
}

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//if(isVisibleToUser){
    if (getArguments() != null) {
        allProducts = getArguments().getParcelableArrayList(ARG_PRODUCTS);
        this.position = getArguments().getInt("KEY_POSITION");
    }

//}}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                     Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_product, container, false);
prodList = (RecyclerView) view.findViewById(R.id.product_list);
prodList.setLayoutManager(new LinearLayoutManager(getActivity()));
productAdapter= new ProductAdapter(getActivity(), allProducts)
prodList.setAdapter(productAdapter);
        return view;
   }
}

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