Develop Reference

My views are giving me a null pointer exception

In my app,I get some data from my server. They are displayed fine,but when I pass them in my Detailed Fragment,then all views are null:(.
So here is my code.
public class MainActivityFragment extends Fragment {
public static final String TAG = "AelApp";
public static ArrayList<MyModel> listItemsList;
RecyclerView myList;
public static MatchReportsAdapter adapter;
public MainActivityFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
updateMatchReport();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
getActivity().setTitle("Match Report");
View rootView = inflater.inflate(R.layout.fragment_main_activity, container, false);
listItemsList = new ArrayList<>();
myList = (RecyclerView)rootView.findViewById(R.id.listview_match_reports);
final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
myList.setHasFixedSize(true);
myList.setLayoutManager(linearLayoutManager);
adapter = new MatchReportsAdapter(getActivity(), listItemsList);
myList.setAdapter(adapter);
return rootView;
}
public void updateMatchReport(){
Intent i = new Intent(getActivity(), MatchReport.class);
getActivity().startService(i);
}
}
Adapter
public class MatchReportsAdapter extends
RecyclerView.Adapter<MatchReportsAdapter.RowHolder>{
private List<MyModel> reportsList;
private Context mContext;
private ImageLoader mImageLoader;
private int focused = 0;
public MatchReportsAdapter(Activity activity, List<MyModel> reportsLists){
this.reportsList = reportsLists;
this.mContext=activity;
}
#Override
public RowHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_items,null);
final RowHolder holder = new RowHolder(v);
return holder;
}
#Override
public void onBindViewHolder(RowHolder holder, int position) {
final MyModel listItems = reportsList.get(position);
holder.itemView.setSelected(focused==position);
holder.getLayoutPosition();
mImageLoader = AppController.getInstance().getImageLoader();
holder.thumbnail.setImageUrl(listItems.getImage(),mImageLoader);
holder.thumbnail.setDefaultImageResId(R.drawable.reddit_placeholder);
holder.name.setText(Html.fromHtml(listItems.getTitle()));
holder.relativeLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String article = listItems.getArticle();
String image = listItems.getImage();
Intent i = new Intent(mContext, DetailedActivity.class);
i.putExtra("articleKey",article);
i.putExtra("imageKey",image);
mContext.startActivity(i);
}
});
}
#Override
public int getItemCount() {
return reportsList.size();
}
public class RowHolder extends RecyclerView.ViewHolder{
protected NetworkImageView thumbnail;
protected TextView name;
protected RelativeLayout relativeLayout;
public RowHolder(View itemView) {
super(itemView);
this.relativeLayout = (RelativeLayout)
itemView.findViewById(R.id.recLayout);
this.thumbnail =
(NetworkImageView)itemView.findViewById(R.id.thumbnail);
this.name = (TextView)itemView.findViewById(R.id.title);
}
}
}
DetailedActivity
public class DetailedActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detailed);
if(savedInstanceState == null){
getSupportFragmentManager()
.beginTransaction()
.add(R.id.detailed_match_reports,new DetailedActivityFragment())
.commit();
}
}
}
DetailedActivityFragment
public class DetailedActivityFragment extends Fragment {
TextView articleTextView;
String image;
String article;
ImageView imageView;
public DetailedActivityFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_detailed_activity, container, false);
articleTextView = (TextView)getActivity().findViewById(R.id.articleTextView);
imageView = (ImageView)getActivity().findViewById(R.id.imageNews);
Intent i = getActivity().getIntent();
article = i.getStringExtra("articleKey");
image = i.getStringExtra("imageKey");
Picasso.with(getActivity()).load(image).into(imageView);
articleTextView.setText(article);
return v;
}
}
All of my data are passed after clicking a row good. I know this as I debug the following lines.
article = i.getStringExtra("articleKey");
image = i.getStringExtra("imageKey");
and see that both String variables are not null. However,the both views(TextView,ImageView) of my detailed fragment are null.
Maybe I am doing something wrong with my xml file,and I don't see it.
activity_main.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/match_reports"
tools:context="theo.testing.androidservices.fragments.MainActivityFragment">
</FrameLayout>
fragment_main_activity
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/recLayout"
tools:context=".activities.MainActivity"
android:background="#fff">
<android.support.v7.widget.RecyclerView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/listview_match_reports"
android:layout_alignParentStart="true"
android:layout_alignParentLeft="true"
/>
</RelativeLayout>
activity_detailed.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/detailed_match_reports"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="theo.testing.androidservices.activities.DetailedActivity"
tools:ignore="MergeRootFrame">
</FrameLayout>
and finally
fragment_detailed_activity
<?xml version="1.0" encoding="utf-8"?>
<ScrollView android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/imageNews"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
xmlns:android="http://schemas.android.com/apk/res/android">
<TextView
android:layout_gravity="center_horizontal"
android:padding="10dp"
android:text="xcvxcvxcv"
android:textColor="#000"
android:layout_marginTop="5dp"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/articleTextView"/>
</ScrollView>
What am I missing?
Thanks
Theo.

Change these
articleTextView = (TextView)getActivity().findViewById(R.id.articleTextView);
imageView = (ImageView)getActivity().findViewById(R.id.imageNews);
to
articleTextView = (TextView)v.findViewById(R.id.articleTextView);
imageView = (ImageView)v.findViewById(R.id.imageNews);
You'r passing data to DetailActivity. So first retrieve in DetailActivity and then pass to DetailFragment.
Also you need to pass data to DetailFragment using Bundle with setArguments(bundle)

Your Textview articleTextView is in the fragment but you are finding it in the activitys xml:
articleTextView = (TextView)getActivity().findViewById(R.id.articleTextView);
insetad you should do:
articleTextView = (TextView)(v.findViewById(R.id.articleTextView));
Do the same for Imageviewl.

How to create a cardView programatically?

So I have this list of city objects (which contain an image, the name of the city, and a integer value). And for each of these city objects I want to programatically create a new cardView and insert it into a fragment. Currently, nothing shows up...
Here is my fragment xml code.
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingTop="24dp"
android:id="#+id/fragCards_LL">
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
Here is the code for my fragment activity.
public class FragmentCards extends Fragment
{
private ArrayList<CityFolders> cityFolders = new ArrayList<>();
private OnCardsFragmentListener mListener;
private LinearLayout linearLayout;
private View view;
public FragmentCards() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the layout for this fragment
view = inflater.inflate(R.layout.fragment_fragment_cards, container, false);
setUpLinearLayout();
setUpCityFolders();
//TextView myText = (TextView) view.findViewById(R.id.fragCards_numberOfCardsTextContent);
//Toast.makeText(getActivity(), myText.getText(), Toast.LENGTH_SHORT).show();
return inflater.inflate(R.layout.fragment_fragment_cards, container, false);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnCardsFragmentListener)
{
mListener = (OnCardsFragmentListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnCheeseCategoriesFragmentListener");
}
}
private void setUpLinearLayout()
{
linearLayout = (LinearLayout) view.findViewById(R.id.fragCards_LL);
linearLayout.setOrientation(LinearLayout.VERTICAL);
linearLayout.setLayoutParams(new NestedScrollView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
}
private void setUpCityFolders()
{
if(!Global_Class.getInstance().getValue().cityFoldersArrayList.isEmpty())
{
cityFolders = Global_Class.getInstance().getValue().cityFoldersArrayList;
for(CityFolders cityFolder : cityFolders)
{
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
lp.setMargins(64,64,64,64);
lp.height = 200;//180dp = 720pixels
lp.width = 1408;//330dp = 1320 pixels.
CardView cityCardView = new CardView(getActivity());// ERROR
cityCardView.setBackgroundColor(000000);
cityCardView.setLayoutParams(lp);
linearLayout.addView(cityCardView, 0);
}
}
}
public interface OnCardsFragmentListener
{
void disableCollapse();
}
}
So, don't know what I am doing wrong here... hope someone can help, maybe point out what im doing wrong?
Also, in my cardView, going horizontally, I want to have an imageview, then a textview, followed by another textview. How would I inflate those parts of the cardView and fill them with an image, and 2 texts from my cityFolder object? Hope you guys can help me with an answer!
Cheers
EDIT:
So i implemented a recycler view and..nothing shows up on the screen... This recycler view just holds simple views with each view having an imageview and a textview, and nothing shows up..
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingTop="24dp"
android:id="#+id/fragCards_LL">
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/fragCards_RecyclerView">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
Here is my xml code for the view for each item in the recycler view
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:src="#drawable/fullstar"
android:id="#+id/fragCardsCity_imageview"
android:layout_gravity="center_vertical"
android:padding="8dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Star City"
android:layout_gravity="center_vertical"
android:id="#+id/fragCardsCity_textView"
android:padding="8dp"/>
</LinearLayout>
And finally, here is my java code.
public class FragmentCards extends Fragment
{
private ArrayList<CityFolders> cityFolders = new ArrayList<>();
private LinearLayout linearLayout;
private View rootView;
private RecyclerView recyclerView;
private CityViewAdapter cityAdapter;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the layout for this fragment
rootView = inflater.inflate(R.layout.fragment_cards, container, false);
linearLayout = (LinearLayout) rootView.findViewById(R.id.fragCards_LL);
recyclerView = (RecyclerView) rootView.findViewById(R.id.fragCards_RecyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
cityAdapter = new CityViewAdapter(getActivity(),getData());
recyclerView.setAdapter(cityAdapter);
recyclerView.setItemAnimator(new DefaultItemAnimator());
return rootView;
}
public static ArrayList<myData> getData()
{
ArrayList<myData> data = new ArrayList<>();
int[] icons = {R.drawable.fullstar,R.drawable.fullstar,R.drawable.fullstar,R.drawable.fullstar};
String[] titles = {"San Francisco","Seattle","Tokyo","Osaka"};
for(int i = 0; i < titles.length && i < icons.length; i++)
{
myData current = new myData();
current.iconId = icons[i];
current.cityName = titles[i];
data.add(current);
}
return data;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
private static class myData
{
private int iconId;
private String cityName;
}
private class CityViewAdapter extends RecyclerView.Adapter<CityViewAdapter.MyViewHolder>
{
private LayoutInflater inflater;
private ArrayList<myData> infoList = new ArrayList<>();
public CityViewAdapter(Context context, ArrayList<myData> data)
{
inflater = LayoutInflater.from(context);
this.infoList = data;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
View view = inflater.inflate(R.layout.fragment_cards_cityview,parent,false);
MyViewHolder holder = new MyViewHolder(view);//special way to avoid "findViewById everytime you make a view
return holder;
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position)
{
myData current = infoList.get(position);
holder.title.setText(current.cityName);
holder.icon.setImageResource(current.iconId);
}
#Override
public int getItemCount() {
return 0;
}
class MyViewHolder extends RecyclerView.ViewHolder
{
TextView title;
ImageView icon;
public MyViewHolder(View itemView)
{
super(itemView);
title = (TextView) itemView.findViewById(R.id.fragCardsCity_textView);
icon = (ImageView) itemView.findViewById(R.id.fragCardsCity_imageview);
}
}
}
}

ViewPager inside every gridView cell

I'm trying to implement a sort of calendar with some timetables.
I created a GridView and since there may be multiple times for the same day I put in every cell a ViewPager. I created all the Adapters but there's a strange issue: the content of the pager is visible only in the first cell of the gridview.
If i put a simple TextView inside a cell so all the contents are shown properly in the 1st, 3rd and 5th cell.
Here are my files:
grid_row.xml : the layout of a single gridview cell:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="60dp"
android:layout_height="60dp"
android:background="#drawable/square"
android:orientation="vertical" >
<TextView
android:id="#+id/row_day"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-bold"
android:textColor="#cfd8dc"
android:textSize="9sp" />
<android.support.v4.view.ViewPager
android:id="#+id/row_orari_pager"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
</LinearLayout>
WhereFragment.java
[...]
public class GridViewCustomAdapter extends BaseAdapter {
ArrayList<Day> officeDay;
public GridViewCustomAdapter(Day[] days) {
officeDay = new ArrayList<Day>(Arrays.asList(days));
}
public int getCount() {
return 7;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
if (row == null) {
LayoutInflater inflater = getActivity().getLayoutInflater();
row = inflater.inflate(R.layout.grid_row, parent, false);
TextView day = (TextView) row.findViewById(R.id.row_day);
ViewPager mPager = (ViewPager) row.findViewById(R.id.row_orari_pager);
day.setText(days[position]);
OrariPagerAdapter mPagerAdapter = new OrariPagerAdapter(getChildFragmentManager());
mPager.setAdapter(mPagerAdapter);
}
return row;
}
public class OrariPagerAdapter extends FragmentStatePagerAdapter {
public ArrayList<Time> currentOrari;
public OrariPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public OrariObjectFragment getItem(int i) {
OrariObjectFragment fragment = new OrariObjectFragment(currentOrari);
Bundle args = new Bundle();
args.putInt(OrariObjectFragment.ARG_OBJECT, i);
fragment.setArguments(args);
return fragment;
}
#Override
public int getCount() {
return 2;
}
#Override
public CharSequence getPageTitle(int position) {
return "";
}
}
#SuppressLint("ValidFragment")
public class OrariObjectFragment extends Fragment {
public static final String ARG_OBJECT = "object";
public ArrayList<Time> orari;
public OrariObjectFragment(ArrayList<Time> currentOrari) {
orari = currentOrari;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.orari_layout, container, false);
final int position = getArguments().getInt(ARG_OBJECT);
TextView orario = (TextView) rootView.findViewById(R.id.row_orario);
orario.setTextColor(Color.parseColor("#ff0000"));
return rootView;
}
}
}
orari_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="#+id/row_orario"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-light"
android:textColor="#607d8b"
android:textSize="15sp"
android:text="aoisjsdasdas"/>
</LinearLayout>
This is the result, so only the first cell is filled and not the other two.
Any advices? Thank you all

if (row == null) {
What about when row isnt null, ie, all the times after the first cell.
if (row == null) {
LayoutInflater inflater = getActivity().getLayoutInflater();
row = inflater.inflate(R.layout.grid_row, parent, false);
}
TextView day = (TextView) row.findViewById(R.id.row_day);
ViewPager mPager = (ViewPager) row.findViewById(R.id.row_orari_pager);
day.setText(days[position]);
OrariPagerAdapter mPagerAdapter = new OrariPagerAdapter(getChildFragmentManager());
mPager.setAdapter(mPagerAdapter);

if (row == null) {
LayoutInflater inflater = getActivity().getLayoutInflater();
row = inflater.inflate(R.layout.grid_row, parent, false);
TextView day = (TextView) row.findViewById(R.id.row_day);
ViewPager mPager = (ViewPager) row.findViewById(R.id.row_orari_pager);
}
day.setText(days[position]);
OrariPagerAdapter mPagerAdapter = new OrariPagerAdapter(getChildFragmentManager());
mPager.setAdapter(mPagerAdapter);

Android GridView displaying incorrect item and fragment displaying on top of another fragment

I am implementing ActionBar Tab to display 3 tabs, each of which contains a GridLayout. The problem arises when the view is scrolled down, the hidden items appear but the order is somehow scrambled. The screen shows only 4 items initially (in a 2 column grid), but when the 5th comes into view, item 1 is shown instead, but the 6th is correct. The 7th and 8th items are also incorrect, and the error is similarly displayed on the other tabs. Scrolling across the tabs also jumbles up the order.
The second problem arises when I implement onItemClickListener on each item in the grid, which is supposed to replace the fragment with one showing larger view. Instead of replacing the view, it sits on top of the display with the bottom fragment showing through.
I can't figure out what's wrong. Here's my code
Main Activity:
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
AppSectionsPagerAdapter mAppSectionsPagerAdapter;
ViewPager mViewPager;
public static String[] mTabItems;
public static int[] mTabImages;
public static GridView mGridview;
public static String[][] itemName = new String[3][8];
public static int [][] itemPics = new int[3][8];
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager());
final ActionBar actionBar = getActionBar();
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mAppSectionsPagerAdapter);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
for (int i = 0; i < mAppSectionsPagerAdapter.getCount(); i++) {
actionBar.addTab(actionBar.newTab().setText(mAppSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
int i = 0;
for (int tab = 1; tab<4; tab++){
for (int item = 1; item<9; item++){
String image = "tab" + tab + "_" + item;
int imageIden = getResources().getIdentifier(image, "drawable","com.tabgriddrawer");
itemPics[tab-1][item-1] = imageIden;
itemName[tab-1][item-1] = image;
i++;
}
}
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
mViewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
public static class AppSectionsPagerAdapter extends FragmentPagerAdapter {
public AppSectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
Fragment frag = new SectionFragment();
Bundle arguments = new Bundle();
arguments.putInt(SectionFragment.ARG_TAB_NUMBER, i);
frag.setArguments(arguments);
return frag;
}
#Override
public int getCount() {
return 3;//set 3 tabs
}
#Override
public CharSequence getPageTitle(int position) {
return "Tab " + (position + 1);
}
}
public static class SectionFragment extends Fragment {
public static final String ARG_TAB_NUMBER = "tab_number";
public static Bundle detailArguments;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final Bundle arg = getArguments();
int tab = arg.getInt(ARG_TAB_NUMBER);
mTabItems = new String[8];
mTabImages = new int[8];
for (int m=0; m<8; m++){
mTabItems[m] = itemName[tab][m];
mTabImages[m] = itemPics[tab][m];
}
View rootView = inflater.inflate(R.layout.fragment_section_gridview, container, false);
CustomGrid adapter = new CustomGrid(getActivity().getApplicationContext(), mTabItems,mTabImages);
mGridview = (GridView) rootView.findViewById(R.id.fragment_grid_view);
mGridview.setAdapter(adapter);
mGridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,int position, long id){
int t = arg.getInt(ARG_TAB_NUMBER);
Fragment itemDetailFragment = new ItemDetailFragment();
detailArguments = new Bundle();
detailArguments.putString("ItemName", itemName[t][position]);
detailArguments.putInt("ImageId", itemPics[t][position]);
itemDetailFragment.setArguments(detailArguments);
FragmentManager fm = getFragmentManager();
Fragment itemFragment = fm.findFragmentById(R.id.pager);
android.support.v4.app.FragmentTransaction ft = fm.beginTransaction();
ft.hide(itemFragment);
ft.replace(R.id.drawer_layout, itemDetailFragment, "detail");
ft.commit();
}
});
return rootView;
}
}
}
Custom Gridview adapter:
public class CustomGrid extends BaseAdapter{
private Context mContext;
private final String[] libraryItem;
private final int[] imageId;
public CustomGrid(Context c,String[] libItem,int[] Imageid ) {
mContext = c;
this.imageId = Imageid;
this.libraryItem = libItem;
}
#Override
public int getCount() {
return libraryItem.length;
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View grid;
LayoutInflater inflater = (LayoutInflater) mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
grid = new View(mContext);
grid = inflater.inflate(R.layout.fragment_gridview_item, null);
TextView textView = (TextView) grid.findViewById(R.id.txtItemName);
ImageView imageView = (ImageView)grid.findViewById(R.id.imageItem);
textView.setText(libraryItem[position]);
imageView.setImageResource(imageId[position]);
} else {
grid = (View) convertView;
}
return grid;
}
}
Item Detail Fragment:
public class ItemDetailFragment extends Fragment {
private Context mContext;
private String mItemDesc;
private int mImageId;
private String mItemName;
static int tab;
static int position;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View view = inflater.inflate(R.layout.fragment_item_detail, container, false);
ImageView image = (ImageView)view.findViewById(R.id.itemimage);
image.setImageResource(mImageId);
TextView itemtext = (TextView)view.findViewById(R.id.itemName);
itemtext.setText(mItemName);
return view;
}
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
ActionBar actionBar = getActivity().getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
mImageId = (int)MainActivity.SectionFragment.detailArguments.getInt("ImageId");
mItemName = (String)MainActivity.SectionFragment.detailArguments.get("ItemName");
}
public void onBackPressed(){
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.main_frame, new MainActivity.SectionFragment());
ft.addToBackStack(null);
ft.commit();
}
}
Main XML
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- moved viewpager to inside drawer layout -->
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
<FrameLayout
android:id="#+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ListView
android:id="#+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="#android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
</android.support.v4.widget.DrawerLayout>
Gridview XML
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/main_frame"
android:layout_width="match_parent"
android:layout_height="match_parent">
<GridView
android:id="#+id/fragment_grid_view"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:columnWidth="90dp"
android:gravity="center"
android:horizontalSpacing="10dp"
android:numColumns="2"
android:stretchMode="columnWidth"
android:verticalSpacing="10dp" >
</GridView>

I didn't look at your whole code. . . only the getView method in your Adapter, cause that is where I suspect the problem is.
When the convertView is not null, you are simply returning convertView. . . this is what is causing the problem. When you do this, you are returning a view that the adapter is attempting to recycle from one gridview position to another. That's why the image from one view is appearing in another. Instead, do this:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View grid;
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
grid = new View(mContext);
grid = inflater.inflate(R.layout.fragment_gridview_item, null);
} else {
grid = (View) convertView;
}
TextView textView = (TextView) grid.findViewById(R.id.txtItemName);
ImageView imageView = (ImageView)grid.findViewById(R.id.imageItem);
textView.setText(libraryItem[position]);
imageView.setImageResource(imageId[position]);
return grid;
}

ViewPagers and PagerAdapters

I am new to Android and am trying a sample application for showing ViewPagers in a Master-Detail Flow using custom PagerAdapters and FragmentStatePagerAdapters. My application has a list of dummy items managed by a SQLiteDatabase which contain a title String, a description String, a Boolean like status, and a list of images (I plan to implement them as downloading from String urls but presently I'm just trying with a single image resource). I am having two problems in the Detail View.
My intention is to use a ViewPager with a FragmentStatePagerAdapter to show the detail view, which consists of a ViewPager with a custom PagerAdapter for showing the list of images, TextView for title and description, a ToggleButton for the like status and a delete button for deleting items from the list.
Issues:
The ViewPager with the custom PagerAdapter does not display the image. It occupies the expected space and swipes performed on it also behave as expected. Only the image is not visible.
[RESOLVED] On using the delete button, I am able to delete the item from the database, and also update the Master View accordingly, but I am not able to update the Detail View, and the app crashes.
Here is my code:
Code that calls ItemDetailActivity.java
#Override
public void onClick(View v) {
Intent detailIntent = new Intent(getContext(), ItemDetailActivity.class);
detailIntent.putExtra(ItemDetailFragment.ARG_LIST_POSITION, holder.position);
getContext().startActivity(detailIntent);
}
ItemDetailActivity.java
public class ItemDetailActivity extends FragmentActivity {
static ItemDetailPagerAdapter idpa;
static ViewPager detailPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item_detail);
idpa = new ItemDetailPagerAdapter(getSupportFragmentManager());
// Show the Up button in the action bar.
getActionBar().setDisplayHomeAsUpEnabled(true);
detailPager = (ViewPager) findViewById(R.id.item_detail_container);
detailPager.setAdapter(idpa);
detailPager.setCurrentItem(getIntent().getIntExtra(ItemDetailFragment.ARG_LIST_POSITION, 0));
}
}
activity_item_detail.xml
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/item_detail_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.trial.piclist.ItemDetailActivity"
tools:ignore="MergeRootFrame" />
ItemDetailFragment.java
public class ItemDetailFragment extends Fragment {
public static final String ARG_ITEM_ID = "item_id";
public static final String ARG_LIST_POSITION = "list_index";
public static final String ARG_TWO_PANE = "is_two_pane";
int position = -1;
long id = -1;
boolean twoPane = false;
ViewPager pager;
private PicItem mItem;
public ItemDetailFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
twoPane = getArguments().getBoolean(ARG_TWO_PANE, false);
position = getArguments().getInt(ARG_LIST_POSITION, -1);
id = getArguments().getLong(ARG_ITEM_ID, -1);
if (id == -1)
id = ItemListFragment.getIdByPosition(position);
setmItem(id);
}
public void setmItem(long id) {
if (id >= 0) {
try {
ItemListActivity.lds.open();
mItem = ItemListActivity.lds.getById(id);
ItemListActivity.lds.close();
} catch (Exception e) {
System.out.println(e.getMessage());
}
if (mItem != null) {
List<String> pics = new ArrayList<String>();
pics.add("1");
pics.add("2");
pics.add("3");
pics.add("4");
pics.add("5");
mItem.setPics(pics);
}
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_item_detail,
container, false);
DetailViewHolder holder = new DetailViewHolder();
pager = (ViewPager) rootView.findViewById(R.id.pager);
ImagePagerAdapter adapter = new ImagePagerAdapter(mItem, getActivity(),
inflater, position);
pager.setAdapter(adapter);
holder.position = getArguments().getInt(ARG_LIST_POSITION);
holder.ttv = (TextView) rootView.findViewById(R.id.item_title);
holder.dtv = (TextView) rootView.findViewById(R.id.item_detail);
holder.likeButton = (ToggleButton) rootView
.findViewById(R.id.item_like);
holder.deleteButton = (Button) rootView.findViewById(R.id.item_delete);
rootView.setTag(holder);
if (mItem != null) {
holder.ttv.setText(mItem.getTitle());
holder.dtv.setText(mItem.getDescription());
holder.likeButton.setChecked(mItem.getIsLiked());
holder.likeButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
ItemListActivity.lds.open();
ItemListActivity.lds.toggleLike(mItem.getId());
mItem.toggleIsLiked();
ItemListActivity.lds.close();
ItemListFragment.listDisplayHelper.toggleLiked(position);
}
});
holder.deleteButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
ItemListActivity.lds.open();
ItemListActivity.lds.removeItem(mItem.getId());
ItemListActivity.lds.close();
ItemListFragment.listDisplayHelper.remove(position);
ItemListActivity.idpa.notifyDataSetChanged();
// What do I do so that the FragmentStatePagerAdapter is
// updated and the viewpager shows the next item.
}
});
}
return rootView;
}
static private class DetailViewHolder {
TextView ttv;
TextView dtv;
ToggleButton likeButton;
Button deleteButton;
int position;
}
}
fragment_item_detail.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="16dp"
tools:context="com.trial.piclist.ItemDetailFragment" >
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="200dip">
</android.support.v4.view.ViewPager>
<TableRow
android:id="#+id/tableRow1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/item_title"
style="?android:attr/textAppearanceLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello"
android:textIsSelectable="true" />
<Space
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1" />
<include
android:layout_width="wrap_content"
android:layout_height="wrap_content"
layout="#layout/controls_layout" />
</TableRow>
<ScrollView
android:id="#+id/descScrollView"
android:layout_width="match_parent"
android:layout_height="0dip"
android:layout_weight="1" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="#+id/item_detail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello" />
</LinearLayout>
</ScrollView>
</LinearLayout>
controls_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<ToggleButton
android:id="#+id/item_like"
android:layout_width="30dip"
android:layout_height="30dip"
android:layout_gravity="right"
android:background="#android:drawable/btn_star"
android:gravity="center"
android:text="#string/like_list_item"
android:textOff="#string/empty_text"
android:textOn="#string/empty_text" />
<Button
android:id="#+id/item_delete"
style="?android:attr/buttonStyleSmall"
android:layout_width="30dip"
android:layout_height="30dip"
android:background="#android:drawable/ic_menu_delete"
android:text="#string/empty_text" />
</LinearLayout>
Custom PagerAdapter
ImagePagerAdapter.java
public class ImagePagerAdapter extends PagerAdapter {
LayoutInflater inflater;
List<View> layouts = new ArrayList<>(5);
// Constructors.
#Override
public Object instantiateItem(ViewGroup container, int position) {
if (layouts.get(position) != null) {
return layouts.get(position);
}
View layout = inflater.inflate(R.layout.detail_image,
((ViewPager) container), true);
try {
ImageView loadSpace = (ImageView) layout
.findViewById(R.id.detail_image_view);
loadSpace.setBackgroundColor(0x000000);
loadSpace.setImageResource(R.drawable.light_grey_background);
loadSpace.setAdjustViewBounds(true);
} catch (Exception e) {
System.out.println(e.getMessage());
}
layout.setTag(images.get(position));
layouts.set(position, layout);
return layout;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
}
#Override
public int getCount() {
return 5;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return (((View) object).findViewById((view.getId())) != null);
}
}
FragmentPagerAdapter
ItemDetailPagerAdapter.java
public class ItemDetailPagerAdapter extends FragmentStatePagerAdapter {
public ItemDetailPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
Fragment fragment = new ItemDetailFragment();
Bundle args = new Bundle();
args.putLong(ItemDetailFragment.ARG_ITEM_ID, ItemListFragment.getIdByPosition(position));
args.putInt(ItemDetailFragment.ARG_LIST_POSITION, position);
args.putBoolean(ItemDetailFragment.ARG_TWO_PANE, ItemListActivity.mTwoPane);
fragment.setArguments(args);
return fragment;
}
#Override
public int getCount() {
openDatabase();
int c = database.getCount();
closeDatabase();
return c;
}
#Override
public int getItemPosition(Object object) {
long mId = ((ItemDetailFragment) object).getmId();
int pos = POSITION_NONE;
openDatabase();
if (database.contains(mId)) {
pos = database.getPositionById(mId);
}
closeDatabase();
return pos;
}
}
Any help is much appreciated. Thanks :)

In your ItemDetailFragment, remove the viewpager from the holder, it should be directly into the returned view, something like this:
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_item_detail,
container, false);
pager = (ViewPager) rootView.findViewById(R.id.pager);
ImagePagerAdapter adapter = new ImagePagerAdapter(mItem, getActivity(),inflater, position);
pager.setAdapter(adapter);
return rootView;
}
and the ViewHolder pattern should be applied inside your PagerAdapter.

In ImagePagerAdapter.java, correct the isViewFromObject method -
#Override
public boolean isViewFromObject(View view, Object object) {
return (view == (View) object);
}
This will correct the issue of the ImageView.
In ItemDetailPagerAdapter.java, override the getItemPosition method -
#Override
public int getItemPosition(Object object) {
int ret = POSITION_NONE;
long id = ((ItemDetailFragment) object).getId();
openDatabase();
if (databaseContains(id)) {
ret = positionInDatabase(id);
}
closeDatabase();
return ret;
}
On deleting call the FragmentStatePagerAdapter.NotifyDataSetChanged() method. This will make the Adapter update itself on deleting.
Although, the FragmentStatePagerAdapter uses a list of Fragments and of stored states to implement the adapter. That is also causing trouble. To remove that, implement your own list of Fragments.