Hi I have Tablayout with Viewpager and i am using Fragment for tablayout. Now in every Tablayout fragments I have Recyclerview and displaying items.Please See this my json response
here in "typeMaster": array i have categories "typeName": "Dogs", and i am displaying typenames in tablayout i have 4 tablayout, and inside typemaster i have subcategoreis named "catMaster": and i am trying to display catmaster data in recyclerview,but the issue is in every fragment it shows last data "catName": "Vitamins & Minerals",
Activity
public class CategoriesActivity extends AppCompatActivity{
private Header myview;
private ArrayList<SubcategoryModel> subct;
private ArrayList<CategoryModel> filelist;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.categoris_activity);
filelist = (ArrayList<CategoryModel>)getIntent().getSerializableExtra("categorylist");
System.out.println("Category list size"+filelist.size());
myview = (Header) findViewById(R.id.categorisactivity_headerView);
myview.setActivity(this);
TabLayout tabLayout = (TabLayout) findViewById(R.id.cat_tab_layout);
for(int i = 0; i < filelist.size(); i++){
subct=filelist.get(i).getItems();
for(int j=0;j<subct.size();j++)
{
}
System.out.println("SubCategory list size"+subct.size());
}
for(int i = 0; i < filelist.size(); i++){
tabLayout.addTab(tabLayout.newTab().setText(filelist.get(i).getCategory_typename()));
ArrayList<SubcategoryModel> subct=filelist.get(i).getItems();
for(int j=0;j<subct.size();j++)
{
}
}
Bundle bundleObject = new Bundle();
bundleObject.putSerializable("key", filelist);
FirstFragment ff=new FirstFragment();
ff.setArguments(bundleObject);
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager viewPager = (ViewPager) findViewById(R.id.categories_pager);
CategoriesAdapter mPagerAdapter = new CategoriesAdapter(getSupportFragmentManager(),tabLayout.getTabCount());
viewPager.setAdapter(mPagerAdapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
public class CategoriesAdapter extends FragmentStatePagerAdapter {
ArrayList<CategoryModel> catlist;
int numoftabs;
public CategoriesAdapter(FragmentManager fm, int numoftabs) {
super(fm);
this.numoftabs = numoftabs;
}
@Override
public Fragment getItem(int position) {
Log.v("adapter", "getitem" + String.valueOf(position)+subct.size());
return FirstFragment.create(position,subct);
}
@Override
public int getCount() {
return numoftabs;
}
}
}
Fragment
public class FirstFragment extends Fragment {
// Store instance variables
public static final String ARG_PAGE = "page";
private int mPageNumber;
private Context mContext;
private int Cimage;
private ArrayList<SubcategoryModel> subcatlist;
private RecyclerView rcylervw;
private ArrayList<CategoryModel> filelist;
ArrayList<SubcategoryModel> subct;
public static FirstFragment create(int pageNumber,ArrayList<SubcategoryModel> subct){
FirstFragment fragment = new FirstFragment();
Bundle args = new Bundle();
args.putInt(ARG_PAGE, pageNumber);
args.putSerializable("key", subct);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mPageNumber = getArguments().getInt(ARG_PAGE);
subct= (ArrayList<SubcategoryModel>) getArguments().getSerializable("key");
System.out.println("Frag Category list size"+subct.size());
/* for(int i = 0; i < filelist.size(); i++){
subct=filelist.get(i).getItems();
for(int j=0;j<subct.size();j++)
{
}
System.out.println("Frag SubCategory list size"+subct.size());
}*/
// image uri get uri of image that saved in directory of app
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
ViewGroup rootView = (ViewGroup) inflater
.inflate(R.layout.test, container, false);
rcylervw=(RecyclerView)rootView.findViewById(R.id.subcategory_recycler_view);
rcylervw.setHasFixedSize(true);
MyAdapter adapter = new MyAdapter(subct);
rcylervw.setAdapter(adapter);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
rcylervw.setLayoutManager(llm);
return rootView;
}
// this method is not very important
}
MyAdapter
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private ArrayList<SubcategoryModel> mDataset;
public static class MyViewHolder extends RecyclerView.ViewHolder {
public TextView mTextView;
public MyViewHolder(View v) {
super(v);
mTextView = (TextView) v.findViewById(R.id.subcategory_text);
}
}
// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(ArrayList<SubcategoryModel> myDataset) {
mDataset = myDataset;
}
// Create new views (invoked by the layout manager)
@Override
public MyAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item_subcategory, parent, false);
// set the view's size, margins, paddings and layout parameters
MyViewHolder vh = new MyViewHolder(v);
return vh;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.mTextView.setText(mDataset.get(position).getSubCategory_name());
}
@Override
public int getItemCount() {
return mDataset.size();
}
}
Output i am getting right now
As you can see it shows same result "Vitamin & Minerals" in every tabs..i want different subcategories instead of same.
I see a lot of problems with your code, but let's get your UI displaying the subcategories since that's your main concern.
Change the getItem in your adapter to this:
@Override
public Fragment getItem(int position) {
ArrayList<SubcategoryModel> subcategories = filelist.get(position).getItems();
Log.v("adapter", "getitem" + String.valueOf(position)+subcategories.size());
return FirstFragment.create(position,subcategories);
}
What caused the problem:
Let's focus on ArrayList<SubcategoryModel> subct in your activity:
First your code did this:
for(int i = 0; i < filelist.size(); i++){
ArrayList<SubcategoryModel> subct=filelist.get(i).getItems();
// for(int j=0;j<subct.size();j++) ...
}
So at the end of this loop subct is set the subcategories of the last category in filelist.
After that, you did another loop to load the tabs, but that used a different subct variable that was declared inside the loop, and that had no effect on the subct field of your activity.
Then you created your view pager and adapter.
In your pager adapter you had this:
@Override
public Fragment getItem(int position) {
Log.v("adapter", "getitem" + String.valueOf(position)+subct.size());
return FirstFragment.create(position,subct);
}
Since subct was set to the last category's subcategories from the loop before, every single fragment created was receiving those subcategories, no matter what position (category) the fragment was for. All I did was change the code to go back to filelist and get the correct category (and subcategories) for the position of the fragment being created.
When you're writing code, you think about what you want the code to do. However, at the point where you run the code and discover you have a problem, you have to forget what you wanted the code to do, then pretend you're the computer and run the code in your head. You want to understand what effect every line of code is having. When you do it that way it's easier to find the problem.
Problem:
There's no way to pass a Serializable ArrayList in a Bundle. Look at the docs page here Bundle docs
Solution:
Change your SubCategoryModel to implement Parcelable and then use bundle.putParcelableArrayList(key, list) and bundle.getParcelableArrayList(key) to pass the ArrayList to the FragmentArgs and get them from the Fragment
this is the main logic of your code I guess... Try it and let me know if you need more help or you find it helpful...
private void parseJsonData() {
try {
listDogs.clear();
JSONArray jsonArray = new JSONArray(loadJSONFromAsset());
JSONObject firstJsonobject = jsonArray.optJSONObject(0);
JSONArray itemListJsonArray = firstJsonobject.optJSONArray("itemList");
JSONObject secondJsonobject = itemListJsonArray.optJSONObject(0);
JSONArray typeMasterArray = secondJsonobject.optJSONArray("typeMaster");
JSONObject thirdJsonobject = typeMasterArray.optJSONObject(0);
JSONArray catMasterArray = thirdJsonobject.optJSONArray("catMaster");
for(int i=0; i<catMasterArray.length(); i++) {
JSONObject jsonObject = catMasterArray.optJSONObject(i);
ModelClass modelClass = new ModelClass();
modelClass.setTypeId(jsonObject.optString("catID"));
modelClass.setTypeName(jsonObject.optString("catName"));
listDogs.add(modelClass);
}
RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(getActivity(), listDogs);
recyclerView.setAdapter(recyclerViewAdapter);
} catch (JSONException e) {
e.printStackTrace();
}
}
Note: To parse data for dogs category I've passed 0 position in variable thirdJsonobject. Pass 1 for cats and 2 for horse and you will find your desired output
Screenshots: Dogs category
来源：https://stackoverflow.com/questions/40149039/viewpager-recyclerview-issue-in-android