Develop Reference

Passing a List From the MainActivity to a Fragment

I have a viewPager activity that makes multiple fragments with custom FragmentPagerAdapter.
I need to get the List<Audio> audioList and use it in my fragment.
Here is a small part of my MainActivity where I make the fragments. I do not think the rest of the MainActivity code is required in order to answer this question.
ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
PagerAdapter pagerAdapter =
new PagerAdapter(getSupportFragmentManager(), MainActivity.this, audioList);
viewPager.setAdapter(pagerAdapter);
// Give the TabLayout the ViewPager
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.setupWithViewPager(viewPager);
// Iterate over all tabs and set the custom view
for (int i = 0; i < tabLayout.getTabCount(); i++) {
TabLayout.Tab tab = tabLayout.getTabAt(i);
tab.setCustomView(pagerAdapter.getTabView(i));
}
Here is my custom FragmentPagerAdapter:
public class PagerAdapter extends FragmentPagerAdapter {
String tabTitles[] = new String[] { "Recommended", "Popular", "Rock", "Pop", "Blues", "Chill" };
Context context;
private List<Audio> audioList;
public PagerAdapter(FragmentManager fm, Context context, List<Audio> audioList) {
super(fm);
this.context = context;
this.audioList = audioList;
}
#Override
public int getCount() {
return tabTitles.length;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new BlankFragment();
case 1:
return new BlankFragment();
case 2:
return new BlankFragment();
case 3:
return new BlankFragment();
case 4:
return new BlankFragment();
case 5:
return new BlankFragment();
}
return null;
}
#Override
public CharSequence getPageTitle(int position) {
// Generate title based on item position
return tabTitles[position];
}
public View getTabView(int position) {
View tab = LayoutInflater.from(context).inflate(R.layout.custom_tab, null);
TextView tv = (TextView) tab.findViewById(R.id.custom_text);
tv.setText(tabTitles[position]);
return tab;
}
}
And I need to get the List<Audio> audioList into my Fragment here:
public class BlankFragment extends Fragment {
public BlankFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.content_view, container, false);
//Get auidoList here
return rootView;
}
I also need to get the title of the tab in the future but my guess is that I would get it similarly to the audioList. If it is not then I could also use help on getting the tab title.
Additionally if the code style is wrong then I am always happy to have some feedback on it aswell.

The traditional way of doing this is by having an instance method that moves it all via a bundle.
Like this:
public class BlankFragment extends Fragment {
public static BlankFragment newInstance(String title, ArrayList<Audio> audioList) {
BlankFragment blankFragment = new BlankFragment();
Bundle bundle = new Bundle();
bundle.putString("Title", title);
bundle.putParcelableArrayList("AudioList", audioList);
blankFragment.setArguments(bundle);
return blankFragment;
}
public BlankFragment() {
// Required empty public constructor
}
private String title;
private ArrayList<Audio> audioList;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle bundle = getArguments();
if (bundle != null) {
title = bundle.getString("Title");
audioList = getArguments().getParcelableArrayList("AudioList");
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.content_view, container, false);
//Get auidoList here
return rootView;
}
}
Obviously your Audio class will need to implement parcelable for this to work. I found a great plugin (Android Parcelable Code Generator) in Android Studio for generating parcelable code that makes that quick and easy.

Refresh current fragment in tabbed layout viewpager

I am trying to refresh the current fragment in the tabbed layout of my viewpager. I have one fragment (UserProgressFragment) that creates the ViewPager and sets the adapter (UserProgressAdapter) along with creating tabbed layout.
In my UserProgressAdapter, in the getItem() method I am returning two other fragments, (UserWeightTrackerFragment and UserCalorieCounterFragment) based on which tab i am on.
My issue is how do i refresh the fragment and update its content/view from the UserCalorieCounterFragment on a button click, because access to the viewpager and adapter are set in the UserProgressFragment? I have considered notifyDataChange for the adapter but i dont know how to call this from this class as it is set up on the UserProgressFragment class. The purpose of wanting to refresh this page is to update a specific view which is a chart, if context is needed.
I have attached the code below:
UserProgressFragment
public class UserProgressFragment extends Fragment{
public static UserProgressFragment newInstance() {
return new UserProgressFragment();
}
public UserProgressFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_user_progress, container, false);
ViewPager viewPager = view.findViewById(R.id.progress_viewpager);
viewPager.setAdapter(new UserProgressTabsAdapter(getChildFragmentManager()));
TabLayout tabLayout = view.findViewById(R.id.progress_sliding_tabs);
tabLayout.setupWithViewPager(viewPager, true);
return view;
}
}
UserProgressTabsAdapter
public class UserProgressTabsAdapter extends FragmentStatePagerAdapter {
private static final int PAGE_COUNT = 2;
private String tabTitles[] = new String[]{"Weight Tracker", "Calorie Counter"};
public UserProgressTabsAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return UserWeightTrackerFragment.newInstance(position);
case 1:
return UserCalorieCounterFragment.newInstance(position + 1);
}
return null;
}
#Override
public int getCount() {
return PAGE_COUNT;
}
#Override
public CharSequence getPageTitle(int position) {
// Generate title based on item position
return tabTitles[position];
}
UserCalorieCounterFragment (need to refresh this one)
public class UserCalorieCounterFragment extends Fragment implements View.OnClickListener, AdapterView.OnItemSelectedListener {
public static final String ARG_PAGE = "ARG_PAGE";
public static UserCalorieCounterFragment newInstance(int page) {
Bundle args = new Bundle();
args.putInt(ARG_PAGE, page);
UserCalorieCounterFragment fragment = new UserCalorieCounterFragment();
fragment.setArguments(args);
return fragment;
}
public UserCalorieCounterFragment() {
// Required empty public constructor
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
int mPage = getArguments().getInt(ARG_PAGE);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_user_calorie_counter, container, false);
Button mAddCalories = view.findViewById(R.id.btn_add_calorie);
mAddCalories.setOnClickListener(this);
return view;
}
#Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.btn_add_calorie:
//REFRESH/UPDATE HERE
break;
}
}

You can create a public method in your fragment which contains the view pager which will contain the notifyDataSetChanged() function. And in the view pager fragment/item, you can call getParentFragment() and type cast it to your parent/first fragment and access that public method to notifyDataSetChanged().

Android tabs show wrong fragments

Hello, I'm trying to implement an Activity with tabs. Some tabs contain a fragment that shows simple list, others a tree view like list.
The fragments with simple list work fine, while I'm having troubles with the one which shows tree view like list: the tree are build properly, but I get them in the wrong tabs. In the first tab I always see the content of the second one, and swiping back or expanding/collapsing the tree produces a new unwanted substitution of the whole tree.
I'm struggling to understand what I'm doing wrong. I hope you can suggest me what to do. Thanks in advance!
Here's my code:
Pager Adapter:
public class PagerAdapter extends FragmentStatePagerAdapter {
private final List<ListFragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public PagerAdapter(FragmentManager manager)
{
super(manager);
}
#Override
public ListFragment getItem(int index) {
return mFragmentList.get(index);
}
#Override
public int getCount()
{
return mFragmentList.size();
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
public void addFragment(int index, boolean tree) {
Bundle b=new Bundle();
String category= Items.getCategoryByIndex(index);
b.putString(Items.CATEGORY,category);
ListFragment fragment;
if(!tree) {
fragment = new ContentFragment();
} else {
fragment = new TreeFragment();
}
fragment.setArguments(b);
mFragmentList.add(fragment);
mFragmentTitleList.add(Items.getCategoryByIndex(index));
}
}
This is the TreeFragment class:
public class TreeFragment extends TreeViewFragment {
TreeListAdapter mAdapter;
public TreeFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Bundle b = getArguments();
String category = (String) b.get(Items.CATEGORY);
GlobalVariables.dataList = Items.getTreeNodeByCategory(category);
GlobalVariables.nodes = TreeViewLists.LoadInitialNodes(GlobalVariables.dataList);
TreeViewLists.LoadDisplayList();
mAdapter = new TreeListAdapter(inflater.getContext());
setListAdapter(mAdapter);
return super.onCreateView(inflater, container, savedInstanceState);
}
}
and in the activity:
public class MyActivity extends AppCompatActivity {
private ViewPager mViewPager;
private PagerAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mViewPager = (ViewPager) findViewById(R.id.viewpager);
mAdapter = new PagerAdapter(getSupportFragmentManager());
// (...) Content creation (...)
mAdapter.addFragment(0, true);
mAdapter.addFragment(1, true);
mAdapter.addFragment(2, true);
mAdapter.addFragment(3, true);
mAdapter.addFragment(4, false);
mAdapter.addFragment(5, false);
mViewPager.setAdapter(mAdapter);
TabLayout tabs = (TabLayout) findViewById(R.id.tabs);
tabs.setupWithViewPager(mViewPager);
}

Android ViewPager doesn't show its Fragments correctly

I'm having an issue with the support library ViewPager. That ViewPager lives inside a fragment and it's composed of 3 tabs: one that will show some information, the second and third show a list of elements (so they both are beeing generated from the same fragment). When I scroll from the first to the second one everything works fine but if I try to scroll from the second one to the third something happens to the fragments and they don't show up again even the PagerTabStrip disappears when this happens. Also I tryed using the same type of fragment for the 3 tabs (the one that disappeared with the list)and everything seems to work fine, so I'm quite bugged about this. Also, the only log on the console related to the issue is this one:
W/FragmentManager: moveToState: Fragment state for StoreListFragment{3fb980e7 #2 id=0x7f0d0080 android:switcher:2131558528:2} not updated inline; expected state 3 found 2
This is the code for my parent Fragment:
public class StoreFragment extends Fragment {
#Bind(R.id.pager) ViewPager mPager;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_store, container, false);
ButterKnife.bind(this, v);
setupViewPager();
return v;
}
private void setupViewPager() {
String[] titles = {getString(R.string.store_information),
getString(R.string.store_offers),
getString(R.string.store_products)
};
mPager.setAdapter(new StoresPagerAdapter(getChildFragmentManager(), titles));
}
}
This is the code for the PagerAdapter:
public class StoresPagerAdapter extends FragmentPagerAdapter {
private String[] mPageTitles;
public StoresPagerAdapter(FragmentManager fm, String[] titles) {
super(fm);
mPageTitles = titles;
}
#Override
public Fragment getItem(int position) {
switch (position){
case 0:
return StoreInfoFragment.newInstance();
//return StoreListFragment.newInstance(position);
case 1:
return StoreListFragment.newInstance(position);
case 2:
return StoreListFragment.newInstance(position);
default:
return null;
}
}
#Override
public int getCount() {
return mPageTitles != null ? mPageTitles.length : 0;
}
#Override
public CharSequence getPageTitle(int position) {
return mPageTitles[position];
}
}
And the one for the Fragment:
public class StoreListFragment extends Fragment implements MyListListener {
#Bind(R.id.store_list) RecyclerView mStoreContentView;
private ArrayList<StoreModel> mStoreContents = new ArrayList<>();
public static StoreListFragment newInstance(int page) {
return new StoreListFragment();
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mStoreContents.add(new Schedule());
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_store_list, container, false);
ButterKnife.bind(this, v);
return v;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setupList();
}
protected void setupList() {
LinearLayoutManager layoutManager = new LinearLayoutManager(this.getActivity());
mStoreContentView.setHasFixedSize(true);
mStoreContentView.setLayoutManager(layoutManager);
mStoreContentView.setAdapter(new ArrayAdapter(this, mStoreContents, R.layout.list_elem_locations));
}
#Override
public void onClickElement(int elementId, String elementName) {
Intent i = new Intent(this.getActivity(), DetailActivity.class);
startActivity(i);
}
}

I think your problem is here:
public static StoreListFragment newInstance(int page) {
return new StoreListFragment();
}
You're not using this page anywhere and you're getting two completely same StoreListFragments. You should add:
Bundle args = new Bundle();
args.putInt("key", page);
fragment.setArguments(args);
And then use this differentiation somewhere.

Can't swipe to next item inside my detail activity after implementing viewpager

I am trying to swipe item(from listview) in my detail activity using viewpager.
I have 20 items in my listview (data parsed from json) Instead of swiping the next/previous item , It's only the same item that I swipe (20 times).
here is my DetailActivity.
public class DetailsActivity extends FragmentActivity {
Article feed;
int pos;
private DescAdapter adapter;
private ViewPager pager;
...
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.item_details);
pos = getIntent().getExtras().getInt("pos");
adapter = new DescAdapter(getSupportFragmentManager());
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
pager.setCurrentItem(pos);
}
public class DescAdapter extends FragmentStatePagerAdapter {
public DescAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getCount() {
return 20;
}
public Fragment getItem(int position) {
return DetailFragment.newInstance(position);
}
}
And my detailFragment
public class DetailFragment extends Fragment {
static DetailFragment newInstance(int position) {
DetailFragment f = new DetailFragment();
return f;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.detail_fragment, container, false);
String displaytitle= getActivity().getIntent().getStringExtra("title");
TextView titleF = (TextView)view.findViewById(R.id.title);
titleF.setText(displaytitle);
...
return view;
}
What am I doing wrong?

You are not using the correct argument:
You send the argument "pos2" but you retrieve the argument "title".
#Override
public Fragment getItem(int position) {
DetailFragment frag = new DetailFragment();
Bundle bundle = new Bundle();
bundle.putInt("fPos",position);
frag.setArguments(bundle);
return frag;
}