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get context after returning from adapter to fragment

I am using contextual action bar in my fragment("UnitsFragment.java") to delete and edit items of recyclerview. But when I come back from recyclerview adapter class("UnitsRv.java"). The context seems to be null. I tried returning context from adapter and it worked for function "prepareSelection". However for "onActionItemClicked" under ActionMode.callback, I need to get context so that I can use alertdialog for editing the items.
The "requireContext()" throws this error: Fragment UnitsFragment{e3a36c8 (b4957397-055a-4b1c-8af2-fee89a3e9b35)} not attached to a context.
Here are my codes.
UnitsFragment.java
public class UnitsFragment extends Fragment {
private static final String TAG = "UnitsFragment";
private RecyclerView recyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager layoutManager;
ArrayList<UnitsList> unitsLists = new ArrayList<>();
Activity mcontext = getActivity();
Context dcontext;
ActionMode actionMode;
public static ArrayList<UnitsList> selectionList = new ArrayList<>();
public static boolean isInActionMode = false;
List<String> list = DatabaseClient.getInstance(getContext())
.getUserDatabase()
.getUnitDao().findUnitNameList();
public UnitsFragment() {
}
private ActionMode.Callback actionModeCallback = new ActionMode.Callback() {
#Override
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
mode.getMenuInflater().inflate(R.menu.menu_item_action, menu);
return true;
}
#Override
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
return false;
}
#Override
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_item_edit:
if (selectionList.size() == 1) {
final EditText editText = new EditText(requireContext());
new AlertDialog.Builder(requireContext())
.setTitle("Rename unit name").setView(editText)
.setPositiveButton("Rename", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
UnitsList unitsList = selectionList.get(0);
unitsList.setUnit_name(editText.getText().toString().trim());
isInActionMode = false;
((UnitsRv) mAdapter).changeDataItem(getCheckedLastPosition(), unitsList);
actionMode.finish();
selectionList.clear();
}
})
.create()
.show();
Toast.makeText(getContext(), "Edit", Toast.LENGTH_SHORT).show();
mode.finish();
return true;
}
case R.id.menu_item_delete:
isInActionMode = false;
((UnitsRv) mAdapter).removeData(selectionList);
Toast.makeText(getContext(), "Delete", Toast.LENGTH_SHORT).show();
actionMode.finish();
selectionList.clear();
return true;
default:
return false;
}
}
#Override
public void onDestroyActionMode(ActionMode mode) {
actionMode = null;
}
};
private int getCheckedLastPosition() {
ArrayList<UnitsList> dataSet = UnitsRv.getDataSet();
for (int i = 0; i < dataSet.size(); i++) {
if (dataSet.get(i).equals(selectionList.get(0))) {
return i;
}
}
return 0;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_units, container, false);
setHasOptionsMenu(true);
dcontext = rootView.getContext();
Log.d(TAG, "onCreateView1: " + dcontext);
recyclerView = rootView.findViewById(R.id.rv_units);
recyclerView.setHasFixedSize(true);
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(),
DividerItemDecoration.HORIZONTAL));
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(),
DividerItemDecoration.VERTICAL));
layoutManager = new GridLayoutManager(getContext(), 2);
recyclerView.setLayoutManager(layoutManager);
for (String string : list) {
unitsLists.add(new UnitsList(string));
}
Log.d(TAG, "onCreateView: " + getContext());
mAdapter = new UnitsRv(mcontext,unitsLists);
recyclerView.setAdapter(mAdapter);
return rootView;
}
#Override
public void onCreateOptionsMenu(#NonNull Menu menu, #NonNull MenuInflater inflater) {
inflater.inflate(R.menu.add, menu);
super.onCreateOptionsMenu(menu, inflater);
}
#Override
public boolean onOptionsItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_item_new:
final View customLayout = getLayoutInflater().inflate(R.layout.add_unit_dialog, null);
final EditText edt_unit_name = customLayout.findViewById(R.id.edt_new_unit_name);
final AlertDialog dialog = new AlertDialog.Builder(getContext())
.setView(customLayout)
.setTitle("Unit name")
.setPositiveButton(android.R.string.ok, null) //Set to null. We override the onclick
.setNegativeButton(android.R.string.cancel, null)
.create();
dialog.setOnShowListener(new DialogInterface.OnShowListener() {
#Override
public void onShow(DialogInterface dialogInterface) {
Button ok_btn = dialog.getButton(AlertDialog.BUTTON_POSITIVE);
Button cancel_btn = dialog.getButton(AlertDialog.BUTTON_NEGATIVE);
ok_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String unit_name = edt_unit_name.getText().toString().trim();
if (!TextUtils.isEmpty(unit_name)) {
String old_unit_name = DatabaseClient.getInstance(getContext())
.getUserDatabase()
.getUnitDao()
.findByUnitName(unit_name);
if (old_unit_name == null) {
DatabaseClient.getInstance(getContext())
.getUserDatabase()
.getUnitDao()
.insertUnits(new UnitsList(unit_name));
unitsLists.add(new UnitsList(unit_name));
dialog.dismiss();
} else {
edt_unit_name.setError("Unit already exists");
}
} else {
edt_unit_name.setError("Can't be empty");
}
}
});
cancel_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dialog.dismiss();
}
});
}
});
dialog.show();
return true;
}
return super.onOptionsItemSelected(item);
}
public void prepareSelection(Context context,int position) {
if(actionMode == null) {
isInActionMode = true;
for (String string : list) {
unitsLists.add(new UnitsList(string));
}
mAdapter = new UnitsRv(context, unitsLists);
Log.d(TAG, "prepareSelection: " + mAdapter);
Log.d(TAG, "prepareSelection1: " + dcontext);
mcontext = (Activity)context;
actionMode = mcontext.startActionMode(actionModeCallback);
mAdapter.notifyDataSetChanged();
if (!selectionList.contains(unitsLists.get(position))) {
selectionList.add(unitsLists.get(position));
}
updateViewCounter();
}
}
private void updateViewCounter() {
int counter = selectionList.size();
if (counter == 1) {
actionMode.setTitle(counter + "item selected");
} else {
actionMode.setTitle(counter + "items selected");
}
}
}
This is my Adapter class.
UnitsRv.java
public class UnitsRv extends RecyclerView.Adapter<UnitsRv.ViewHolder> {
private static final String TAG = "UnitsRv";
private static ArrayList<UnitsList> munitsLists = new ArrayList<>();
UnitsFragment unitsFragment = new UnitsFragment();
Context mcontext;
public UnitsRv(Context context,ArrayList<UnitsList> unitsLists) {
mcontext = context;
munitsLists = unitsLists;
}
class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
TextView unit_name;
public ViewHolder(View v) {
super(v);
unit_name = v.findViewById(R.id.unit_name);
v.setOnLongClickListener(this);
}
#Override
public void onClick(View view) {
if (UnitsFragment.isInActionMode){
unitsFragment.prepareSelection(mcontext,getAdapterPosition());
notifyItemChanged(getAdapterPosition());
}
}
#Override
public boolean onLongClick(View view) {
Log.d(TAG, "onLongClick: " + getAdapterPosition());
unitsFragment.prepareSelection(view.getContext(),getAdapterPosition());
return true;
}
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.units_item, parent, false);
return new ViewHolder(itemView);
}
#Override
public void onBindViewHolder(#NonNull final ViewHolder holder, final int position) {
holder.unit_name.setText(munitsLists.get(position).getUnit_name());
if (UnitsFragment.isInActionMode){
if (UnitsFragment.selectionList.contains(munitsLists.get(position))){
holder.itemView.setBackgroundResource(R.color.colorSelected);
}
}
}
#Override
public int getItemCount() {
return munitsLists.size();
}
public static ArrayList<UnitsList> getDataSet() {
return munitsLists;
}
public void changeDataItem(int position, UnitsList unitsList) {
munitsLists.set(position, unitsList);
notifyDataSetChanged();
}
public void removeData(ArrayList<UnitsList> list) {
for (UnitsList unitsList : list) {
munitsLists.remove(unitsList);
}
notifyDataSetChanged();
}
}

First, you should not create instance of your UnitsFragment inside your adapter.
You can use EventBus to communicate between Activities, Fragments, Adapters, etc.
Or You can do your task using interface. like below.
Create an interface like this
public interface AdapterCallback {
void prepareSelection(Context context,int position);
}
In your UnitsFragment implement the above interface. like the following
public class UnitsFragment extends Fragment implements AdapterCallback{
// your other codes
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_units, container, false);
setHasOptionsMenu(true);
// .... your other codes
Log.d(TAG, "onCreateView: " + getContext());
// modify below line like this
mAdapter = new UnitsRv(mcontext, unitsLists, this); // here you have to pass an extra parameter that will implement your callback method from adapter.
recyclerView.setAdapter(mAdapter);
return rootView;
}
// ... you other codes
#Override
public void prepareSelection(Context context,int position) {
if(actionMode == null) {
isInActionMode = true;
for (String string : list) {
unitsLists.add(new UnitsList(string));
}
mAdapter = new UnitsRv(context, unitsLists,this); // add this as parameter.
Log.d(TAG, "prepareSelection: " + mAdapter);
Log.d(TAG, "prepareSelection1: " + dcontext);
mcontext = (Activity)context;
actionMode = mcontext.startActionMode(actionModeCallback);
mAdapter.notifyDataSetChanged();
if (!selectionList.contains(unitsLists.get(position))) {
selectionList.add(unitsLists.get(position));
}
updateViewCounter();
}
}
// other codes
}
Now, inside your Adapter you need to add an extra argument in constructor of UnitsRv and call your interface method from adapter ussing mAdapterCallback.
public class UnitsRv extends RecyclerView.Adapter<UnitsRv.ViewHolder> {
private static final String TAG = "UnitsRv";
private static ArrayList<UnitsList> munitsLists = new ArrayList<>();
UnitsFragment unitsFragment = new UnitsFragment(); // remove this line
private AdapterCallback mAdapterCallback; // add this line
Context mcontext;
public UnitsRv(Context context,ArrayList<UnitsList> unitsLists, AdapterCallback callback) {
mcontext = context;
munitsLists = unitsLists;
this.mAdapterCallback = callback; // add this line
}
class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
TextView unit_name;
public ViewHolder(View v) {
super(v);
unit_name = v.findViewById(R.id.unit_name);
v.setOnLongClickListener(this);
}
#Override
public void onClick(View view) {
if (UnitsFragment.isInActionMode){
mAdapterCallback.prepareSelection(mcontext,getAdapterPosition()); // modify this line
notifyItemChanged(getAdapterPosition());
}
}
#Override
public boolean onLongClick(View view) {
Log.d(TAG, "onLongClick: " + getAdapterPosition());
mAdapterCallback.prepareSelection(view.getContext(),getAdapterPosition()); // modify this line
return true;
}
}
// your other codes....
}

You should check for your fragment is attached or not with isAdded()
place if(!isAdded()) return in your onActionItemClicked. and replace requireContext() with getContext() because requireContext() always throws IllegalStateException if fragment is not attached.

override onAttach method to save context in your fragment.
#Override
public void onAttach(Context context) {
super.onAttach(context);
this.context= context;
}
Hope this helps.

How to use ParseObjects with a RecyclerView?

I am attempting to pull data from my parse server and display an image and text within a RecyclerView of CardViews. I have encountered a few issues, some of which may not have been corrected appropriately, so please feel free to correct any novice code you find below outside of my two current issues. Finally my two issues are.
The data does not display initially. I have 3 tabs in a ViewPager and I have to swipe over twice in order for it to display. If I'm on tab 1 the data doesn't appear until I swipe to tab 3 and return to tab 1, and vice versa. Because there isn't a tab 4, tab 2 never displays.
The second issue I am currently faced with is that at times the data will not match up. It will have the picture from one row matched with the description from another entity.
Below is my MusicFragment.java
public class MusicFragment extends Fragment {
private ArrayList<String> titles = new ArrayList<>();
private ArrayList<Bitmap> bitmaps = new ArrayList<>();
private ArrayList<String> descriptions = new ArrayList<>();
private boolean notComplete = true;
public MusicFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
RecyclerView musicRecycler = (RecyclerView)inflater.inflate(
R.layout.fragment_music, container, false);
if (notComplete) {
// Get the MusicFragImages class as a reference.
ParseQuery<ParseObject> query = new ParseQuery<>("MusicFragImages");
query.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> objects, ParseException e) {
if (e == null) {
for (ParseObject object : objects) {
String description = (String) object.get("description");
ParseFile file = (ParseFile) object.get("image");
String title = (String) object.get("title");
titles.add(title);
descriptions.add(description);
file.getDataInBackground(new GetDataCallback() {
#Override
public void done(byte[] data, ParseException e) {
if (e == null && data != null) {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
bitmaps.add(bitmap);
}
}
});
}
} else {
Toast.makeText(getContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
});
notComplete = false;
}
// Create captioned images and registers it to the adapter.
CaptionedImagesAdapter adapter = new CaptionedImagesAdapter(titles, bitmaps, descriptions);
musicRecycler.setAdapter(adapter);
// Set up the layout.
GridLayoutManager layoutManager = new GridLayoutManager(getActivity(), 1);
musicRecycler.setLayoutManager(layoutManager);
adapter.setListener(new CaptionedImagesAdapter.Listener() {
public void onClick(int position) {
Intent intent;
switch (position) {
case 0:
intent = new Intent(getActivity(), AudioActivity.class);
getActivity().startActivity(intent);
break;
case 1:
intent = new Intent(getActivity(), VideoActivity.class);
getActivity().startActivity(intent);
break;
}
}
});
return musicRecycler;
}
}
Additionally, here is my CaptionedImagesAdapter
class CaptionedImagesAdapter extends
RecyclerView.Adapter<CaptionedImagesAdapter.ViewHolder> {
private final ArrayList<String> captions;
private final ArrayList<Bitmap> bitmaps;
private final ArrayList<String> descriptions;
private Listener listener;
interface Listener {
void onClick(int position);
}
public static class ViewHolder extends RecyclerView.ViewHolder {
private final CardView cardView;
public ViewHolder(CardView v) {
super(v);
cardView = v;
}
}
public CaptionedImagesAdapter(ArrayList<String> captions, ArrayList<Bitmap> bitmaps, ArrayList<String> descriptions) {
this.captions = captions;
this.bitmaps = bitmaps;
this.descriptions = descriptions;
}
#Override
public int getItemCount() {
return captions.size();
}
public void setListener(Listener listener) {
this.listener = listener;
}
#Override
public CaptionedImagesAdapter.ViewHolder onCreateViewHolder(
ViewGroup parent, int viewType) {
CardView cv = (CardView) LayoutInflater.from(parent.getContext()).inflate(R.layout.card_selection_2, parent, false);
return new ViewHolder(cv);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
final int index = position;
// Creates a CardView
CardView cardView = holder.cardView;
ImageView imageView = cardView.findViewById(R.id.type_image);
imageView.setImageBitmap(bitmaps.get(index));
imageView.setContentDescription(descriptions.get(index));
// Populate the caption.
TextView textView = cardView.findViewById(R.id.type_text);
textView.setText(captions.get(index));
cardView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v){
if (listener != null)
listener.onClick(index);
}
});
}
}
FOR REFERENCE...... if needed MainActivity.java is below
public class MainActivity extends AppCompatActivity {
// Variables for the audio player.
public static MediaPlayer mediaPlayer;
public static int albumId;
public static int currentSong = -1;
public static boolean isPlaying = false;
private static int[] songs;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Attach the SectionsPageAdapter to the ViewPager
SectionsPageAdapter pagerAdapter = new SectionsPageAdapter(getSupportFragmentManager());
ViewPager pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(pagerAdapter);
int currentTab = 0;
pager.setCurrentItem(currentTab);
// Attach the ViewPager to the TabLayout
TabLayout tabLayout = (TabLayout)findViewById(R.id.tabs);
tabLayout.setupWithViewPager(pager);
// Starts the player.
player();
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the app bar.
getMenuInflater().inflate(R.menu.menu_main, menu);
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
Intent intent;
switch (item.getItemId()) {
case R.id.action_contact:
intent = new Intent(MainActivity.this, ContactActivity.class);
startActivity(intent);
return true;
case R.id.action_cart:
intent = new Intent(this, CartActivity.class);
startActivity(intent);
return true;
case R.id.action_member:
intent = new Intent(this, ProfileActivity.class);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private class SectionsPageAdapter extends FragmentPagerAdapter {
public SectionsPageAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getCount() {
return 3;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new MusicFragment();
case 1:
return new ArtFragment();
case 2:
return new FashionFragment();
}
return null;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return getResources().getText(R.string.title_music);
case 1:
return getResources().getText(R.string.title_art);
case 2:
return getResources().getText(R.string.title_fashion);
}
return null;
}
}
private void player() {
/*Create a background thread that will automatically advance to
* the next song, as long as there is a next song.*/
// Get the songs.
songs = AudioData.audio[albumId].getSongs();
final Handler handler = new Handler();
handler.post(new Runnable() {
#Override
public void run() {
if (isPlaying) {
if (!(mediaPlayer.isPlaying()) && currentSong < songs.length - 1) {
mediaPlayer.stop();
mediaPlayer.reset();
currentSong++;
mediaPlayer = MediaPlayer.create(MainActivity.this, songs[currentSong]);
mediaPlayer.start();
isPlaying = true;
}
//Set the flag to false at the end of the album.
if (currentSong == songs.length) {
isPlaying = false;
}
}
handler.postDelayed(this, 1000);
}
});
}
#Override
public void onBackPressed() {
super.onBackPressed();
finishAffinity();
}
}
Thanks again to Harikumar for correcting the first issue. I ended up correcting the second issue with the code below. It was within the enhance for loop.
for (ParseObject object : objects) {
String description = (String) object.get("description");
ParseFile file = (ParseFile) object.get("image");
String title = (String) object.get("title");
Bitmap bitmap;
titles.add(title);
descriptions.add(description);
byte[] data;
try {
data = file.getData();
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
bitmaps.add(bitmap);
adapter.notifyDataSetChanged(); //notify your adapter that data has changed
} catch (ParseException pe) {
Toast.makeText(getContext(), pe.getMessage(), Toast.LENGTH_SHORT).show();
}
}

Data will be updated if you notify your adapter CaptionedImagesAdapter. Try modifying the code to:
public class MusicFragment extends Fragment {
private ArrayList<String> titles = new ArrayList<>();
private ArrayList<Bitmap> bitmaps = new ArrayList<>();
private ArrayList<String> descriptions = new ArrayList<>();
private CaptionedImagesAdapter adapter;
private boolean notComplete = true;
public MusicFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
RecyclerView musicRecycler = (RecyclerView)inflater.inflate(
R.layout.fragment_music, container, false);
GridLayoutManager layoutManager = new GridLayoutManager(getActivity(), 1);
musicRecycler.setLayoutManager(layoutManager);
adapter = new CaptionedImagesAdapter(titles, bitmaps, descriptions);
musicRecycler.setAdapter(adapter);
if (notComplete) {
// Get the MusicFragImages class as a reference.
ParseQuery<ParseObject> query = new ParseQuery<>("MusicFragImages");
query.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> objects, ParseException e) {
if (e == null) {
for (ParseObject object : objects) {
String description = (String) object.get("description");
ParseFile file = (ParseFile) object.get("image");
String title = (String) object.get("title");
titles.add(title);
descriptions.add(description);
file.getDataInBackground(new GetDataCallback() {
#Override
public void done(byte[] data, ParseException e) {
if (e == null && data != null) {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
bitmaps.add(bitmap);
adapter.notifyDataSetChanged(); //notify your adapter that data has changed
}
}
});
}
} else {
Toast.makeText(getContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
});
notComplete = false;
}
adapter.setListener(new CaptionedImagesAdapter.Listener() {
public void onClick(int position) {
Intent intent;
switch (position) {
case 0:
intent = new Intent(getActivity(), AudioActivity.class);
getActivity().startActivity(intent);
break;
case 1:
intent = new Intent(getActivity(), VideoActivity.class);
getActivity().startActivity(intent);
break;
}
}
});
return musicRecycler;
}
}
Here is a small optimization for your 2nd solution: update notifyDataSetChanged() only once after the for loop (put it just outside the for loop). This is better in terms of performance.

unable to fetch images in image slider in fragment

When I extend an Activity this works fine, but when extending ActivityFragment I get an error:
unable to resolve constructor
At this line: BaseViewPagerAdapter<String> adapter = new BaseViewPagerAdapter<String>(this). I'm just fetching the image from a URL and displaying it in an image slider. If anyone knows any links or tutorials feel free to suggest me. Thanks.
HomeActivity.java
public class HomeActivity extends Fragment {
private String[] paths = {"http://reviewsimpact.com/wp-content/uploads/2016/04/Patanjali-products-list-1024x385.png",
"https://4.bp.blogspot.com/-3-qgzGwoQ3o/Vuqb1a0g6RI/AAAAAAAAATc/FZjOTm0VUBgXsw3VnWz3RorARUUUgl32g/s1600/Baba%2BRamdev%2BPatanjali%2BProducts%2BList%2Bwith%2BPrice%2Blatest%2B-%2BTipsmonk.jpg",
"http://patanjalistores.com/wp-content/uploads/2015/08/maxresdefault-1920x692.jpg",
"https://aos.iacpublishinglabs.com/question/aq/700px-394px/poems-fruits-vegetables_8d6a91e11da7d63.jpg?domain=cx.aos.ask.com",
"https://i.ytimg.com/vi/2IVR8BrUESQ/maxresdefault.jpg"};
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_main, container, false);
AutoScrollViewPager mViewPager = (AutoScrollViewPager) v.findViewById(R.id.viewPager);
mViewPager = (AutoScrollViewPager)v.findViewById(R.id.viewPager);
BaseViewPagerAdapter<String> adapter = new BaseViewPagerAdapter<String>(this) {
#Override
public void loadImage(ImageView view, int position, String url) {
Picasso.with(getActivity().getApplicationContext()).load(url).into(view);
}
#Override
public void setSubTitle(TextView textView, int position, String s) {
textView.setText("");
}
};
mViewPager.setAdapter(adapter);
adapter.add(initData());
return v;
}
private List<String> initData() {
List<String> data = new ArrayList<>();
Picture picture ;
for (int i = 0 ; i < paths.length ;i++){
data.add(paths[i]);
}
return data;
}
}
BaseBaseViewPagerAdapter.java
public abstract class BaseViewPagerAdapter<T> extends PagerAdapter implements ViewPager.OnPageChangeListener{
private List<T> data = new ArrayList<>();
private Context mContext;
private AutoViewPager mView;
private OnAutoViewPagerItemClickListener listener;
public BaseViewPagerAdapter(List<T> t) {
this.data = t;
}
public BaseViewPagerAdapter(Context context, OnAutoViewPagerItemClickListener listener) {
this.mContext = context;
this.listener = listener;
}
public BaseViewPagerAdapter(Context context, List<T> data) {
this.mContext = context;
this.data = data;
}
public BaseViewPagerAdapter(Context context, List<T> data,OnAutoViewPagerItemClickListener listener) {
this.mContext = context;
this.data = data;
this.listener = listener;
}
public void init(AutoViewPager viewPager,BaseViewPagerAdapter adapter){
mView = viewPager;
mView.setAdapter(this);
mView.addOnPageChangeListener(this);
if (data == null || data.size() == 0){
return;
}
//设置初始为中间，这样一开始就能够往左滑动了
int position = Integer.MAX_VALUE/2 - (Integer.MAX_VALUE/2) % getRealCount();
mView.setCurrentItem(position);
if (!mView.isStart()) {
mView.start();
mView.updatePointView(getRealCount());
}
}
public void setListener(OnAutoViewPagerItemClickListener listener) {
this.listener = listener;
}
public void add(T t){
data.add(t);
notifyDataSetChanged();
mView.updatePointView(getRealCount());
}
public void add(List<T> list){
if (data == null) {
data = new ArrayList<>();
}
data.addAll(list);
notifyDataSetChanged();
mView.start();
mView.updatePointView(getRealCount());
}
public void init(List<T> list){
if (data == null) {
data = new ArrayList<>();
}
data.clear();
data.addAll(list);
notifyDataSetChanged();
if (!mView.isStart()) {
mView.start();
mView.updatePointView(getRealCount());
}
}
#Override
public int getCount() {
return (data == null || data.size() == 0 ) ? 0 : Integer.MAX_VALUE;
}
public int getRealCount(){
return data == null ? 0 : data.size();
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((ImageView) object);
}
#Override
public Object instantiateItem(ViewGroup container, final int position) {
ImageView view = (ImageView) LayoutInflater.from(mContext)
.inflate(R.layout.imageview,container,false);
loadImage(view,position, data.get(position % getRealCount()));
container.addView(view);
//设置标题(不知道为什么标题跟图片对不上，所以做了如下处理，有大神看到帮忙看看。。。)
if (mView.getSubTitle() != null){
if (position == 0){
setSubTitle(mView.getSubTitle(),position,data.get((getRealCount() - 1)));
}else {
setSubTitle(mView.getSubTitle(),position,data.get((position - 1) % getRealCount()));
}
}
view.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (listener != null) {
listener.onItemClick(position % getRealCount(),data.get(position % getRealCount()));
}
}
});
return view;
}
public abstract void loadImage(ImageView view,int position,T t);
public abstract void setSubTitle(TextView textView,int position,T t);
#Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
mView.onPageSelected(position % getRealCount());
}
#Override
public void onPageScrollStateChanged(int state) {
}
public interface OnAutoViewPagerItemClickListener<T> {
void onItemClick(int position,T t);
}
}
MainActivity.java
public class MainActivity extends FragmentActivity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home_activity);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.list_slidermenu);
mDrawerLayout.setDrawerShadow(R.drawable.navigation_drawer_shadow, GravityCompat.START);
if (savedInstanceState == null) {
// on first time display view for first nav item
displayView(0);
}
}
private void displayView(int position) {
Fragment fragment = null;
switch (position) {
case 0:
fragment = new HomeActivity();
break;
default:
break;
}
if (fragment != null) {
android.app.FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
// update selected item and title, then close the drawer
mDrawerLayout.closeDrawer(mDrawerList);
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
}
}

How to start datepicker dialog(daterangepicker) from fragment?

I am using a library to select date range, from here
link to that class
I don't know how to use DateRangePicker from fragment and how to use it, to store data.
Here is my code.
Fragment class:
public class LaborerProfile extends Fragment implements DateRangePickerFragment.OnDateRangeSelectedListener {
Switch switch1;
DateRangePickerFragment.OnDateRangeSelectedListener onDateRangeSelectedListener;
TextView Name,Phone_num,Skill,Age,Gender,Village;
RatingBar ratingBar;
String startDate;
String endDate;
public LaborerProfile() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
makeJsonArryReq();
}
#TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView= inflater.inflate(R.layout.laborer_profile, container, false);
switch1 = (Switch) rootView.findViewById(R.id.switch1);
Name = (TextView)rootView.findViewById(R.id.Name_L);
Phone_num = (TextView)rootView.findViewById(R.id.Phone_L);
Skill = (TextView)rootView.findViewById(R.id.Skill_L);
Age = (TextView)rootView.findViewById(R.id.Age_L);
Gender = (TextView)rootView.findViewById(R.id.Gender_L);
Village = (TextView)rootView.findViewById(R.id.Village_L);
ratingBar = (RatingBar) rootView.findViewById(R.id.Rating_L);
switch1.setChecked(true);
switch1.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton, boolean bChecked) {
if (bChecked) {
showDateRangePicker();
// /startActivity(new Intent(getActivity(),BusinessActivity.class));
} else {
}
}
});
if (switch1.isChecked()) {
} else {
}
return rootView;
}
public void showDateRangePicker(){
DateRangePickerFragment dateRangePickerFragment= DateRangePickerFragment.newInstance(onDateRangeSelectedListener, false);
dateRangePickerFragment.show(getFragmentManager(),"datePicker");
}
private void makeJsonArryReq() {
// showProgressDialog();
String URL_PROFILE_L="http://192.168.43.160/webservice/Lprofile.php?phone_num_l="+ Const.USER_ID;
Log.d("tirth", URL_PROFILE_L);
JsonArrayRequest req = new JsonArrayRequest(URL_PROFILE_L,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
if (response.length() > 0) {
for (int i = 0; i < response.length(); i++) {
JSONObject jsonObject = response.getJSONObject(i);
if (!jsonObject.isNull("user_name_l")) {
Name.setText(jsonObject.getString("user_name_l"));
}
if (!jsonObject.isNull("phone_num_l")) {
Phone_num.setText(jsonObject.getString("phone_num_l"));
}
if (!jsonObject.isNull("age_l")){
Age.setText(jsonObject.getString("age_l"));
}
if (!jsonObject.isNull("gender_l")){
if(jsonObject.getString("gender_l").equals("1")){
Gender.setText("Male");
}else{
Gender.setText("Female");
}
}
if (!jsonObject.isNull("village_l")){
Village.setText(jsonObject.getString("village_l"));
}
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
// hideProgressDialog();
}
});
AppController.getInstance().addToRequestQueue(req);
}
#Override
public void onDateRangeSelected(int startDay, int startMonth, int startYear, int endDay, int endMonth, int endYear) {
Log.d("range : ","from: "+startDay+"-"+startMonth+"-"+startYear+" to : "+endDay+"-"+endMonth+"-"+endYear );
}
}
and I haven't changed the fragment provided from GitHub
public class DateRangePickerFragment extends DialogFragment implements View.OnClickListener{
private OnDateRangeSelectedListener onDateRangeSelectedListener;
private TabHost tabHost;
private DatePicker startDatePicker;
private DatePicker endDatePicker;
private Button butSetDateRange;
boolean is24HourMode;
public DateRangePickerFragment() {
// Required empty public constructor
}
public static DateRangePickerFragment newInstance(OnDateRangeSelectedListener callback, boolean is24HourMode) {
DateRangePickerFragment dateRangePickerFragment = new DateRangePickerFragment();
dateRangePickerFragment.initialize(callback, is24HourMode);
return dateRangePickerFragment;
}
public void initialize(OnDateRangeSelectedListener callback,
boolean is24HourMode) {
onDateRangeSelectedListener = callback;
this.is24HourMode = is24HourMode;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.date_range_picker, container, false);
getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);
tabHost = (TabHost) root.findViewById(R.id.tabHost);
butSetDateRange = (Button) root.findViewById(R.id.but_set_time_range);
startDatePicker = (DatePicker) root.findViewById(R.id.start_date_picker);
endDatePicker = (DatePicker) root.findViewById(R.id.end_date_picker);
butSetDateRange.setOnClickListener(this);
tabHost.findViewById(R.id.tabHost);
tabHost.setup();
TabHost.TabSpec startDatePage = tabHost.newTabSpec("start");
startDatePage.setContent(R.id.start_date_group);
startDatePage.setIndicator("Start Date");
TabHost.TabSpec endDatePage = tabHost.newTabSpec("end");
endDatePage.setContent(R.id.end_date_group);
endDatePage.setIndicator("End Date");
tabHost.addTab(startDatePage);
tabHost.addTab(endDatePage);
return root;
}
#Override
public void onStart() {
super.onStart();
if (getDialog() == null)
return;
getDialog().getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.WRAP_CONTENT);
}
public void setOnDateRangeSelectedListener(OnDateRangeSelectedListener callback) {
this.onDateRangeSelectedListener = callback;
}
#Override
public void onClick(View v) {
dismiss();
onDateRangeSelectedListener.onDateRangeSelected(startDatePicker.getDayOfMonth(),startDatePicker.getMonth(),startDatePicker.getYear(),
endDatePicker.getDayOfMonth(),endDatePicker.getMonth(),endDatePicker.getYear());
}
public interface OnDateRangeSelectedListener {
void onDateRangeSelected(int startDay, int startMonth, int startYear, int endDay, int endMonth, int endYear);
}
}

Android GridView, AsyncTask and screen rotation

i have a problem with handling screen rotation and AsyncTask in my activity.
Here's the problem:
I have a MainActivity which has inside a PostersFragment, who manages the layout. Inside it there is a GridView to populate with some images fetched by an AsyncTask.
When i rotate the device it messess up, and i can see an old GridView behind the actual GridView.
It surely is a problem bound to recreation of the activity, i googled a lot and found the setRetainInstance(true) method, i tried to call it in my fragment but nothing changed.
Here's the MainActivity code:
public class MainActivity extends ActionBarActivity {
private final String POSTERSFRAGMENT_TAG ="PFTG";
private DrawerLayout mDrawer;
private ListView mDrawerListView;
private Toolbar toolbar;
private ActionBarDrawerToggle mDrawerToggle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getFragmentManager().beginTransaction().add(R.id.frame_container, new PostersFragment(), POSTERSFRAGMENT_TAG).commit();
String[] drawerChoices = getResources().getStringArray(R.array.drawer_choices_array);
mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerListView = (ListView) findViewById(R.id.left_drawer);
mDrawerListView.setAdapter(new ArrayAdapter<String>(this, R.layout.drawer_list_item, drawerChoices));
mDrawerListView.setOnItemClickListener(new DrawerItemClickListener());
toolbar = (Toolbar) findViewById(R.id.main_activity_toolbar);
if(toolbar!=null){
toolbar.setTitle(getResources().getString(R.string.app_name));
setSupportActionBar(toolbar);
}
mDrawerToggle = new ActionBarDrawerToggle(this,mDrawer,toolbar,R.string.drawer_open,R.string.drawer_close){
#Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
}
#Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
}
};
mDrawer.setDrawerListener(mDrawerToggle);
}
private class DrawerItemClickListener implements ListView.OnItemClickListener{
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id){
String x =parent.getItemAtPosition(position).toString();
if(x.equals(getString(R.string.trending_drawer_option))) {
PostersFragment fragment = new PostersFragment();
getFragmentManager().beginTransaction().replace(R.id.frame_container, fragment).commit();
mDrawer.closeDrawer(mDrawerListView);
}
if(x.equals(getString(R.string.bookmarked_drawer_option))){
BookmarksFragment fragment = new BookmarksFragment();
getFragmentManager().beginTransaction().replace(R.id.frame_container,fragment).commit();
mDrawer.closeDrawer(mDrawerListView);
}
if(x.equals(getString(R.string.settings_drawer_option))){
mDrawer.closeDrawer(mDrawerListView);
Intent intent = new Intent(getApplicationContext(),SettingsActivity.class);
startActivity(intent);
}
}
}
#Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
mDrawerToggle.syncState();
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
#Override
public boolean onPrepareOptionsMenu(Menu menu) {
boolean drawerOpen = mDrawer.isDrawerOpen(mDrawerListView);
return super.onPrepareOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if(mDrawerToggle.onOptionsItemSelected(item))
return true;
return super.onOptionsItemSelected(item);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
return true;
}
}
And the PostersFragment code:
public class PostersFragment extends android.app.Fragment {
public static final int MAX_PAGES = 50;
public int mPagesLoaded = 0;
private ImageAdapter mImages;
public boolean mIsLoading = false;
public TextView loadingText;
private SharedPreferences sharedPrefs;
private SharedPreferences.OnSharedPreferenceChangeListener spChanged;
public PostersFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mImages = new ImageAdapter(getActivity());
View view = inflater.inflate(R.layout.fragment_main,container,false);
loadingText = (TextView) view.findViewById(R.id.loadingTextView);
loadingText.setVisibility(View.GONE);
sharedPrefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
spChanged = new SharedPreferences.OnSharedPreferenceChangeListener() {
#Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
mImages.clear();
mPagesLoaded=0;
}
};
sharedPrefs.registerOnSharedPreferenceChangeListener(spChanged);
initGrid(view);
startLoading();
return view;
}
private void startLoading()
{
if(mPagesLoaded>=MAX_PAGES)
return;
if(mIsLoading==true)
return;
mIsLoading=true;
if(loadingText!=null)
loadingText.setVisibility(View.VISIBLE);
new FetchPageTask().execute(mPagesLoaded + 1);
}
private void stopLoading()
{
if(mIsLoading==false)
return;
if(mIsLoading==true)
mIsLoading=false;
if(loadingText!=null)
loadingText.setVisibility(View.GONE);
}
private void initGrid(View view)
{
GridView gridView = (GridView) view.findViewById(R.id.gridView);
if(gridView==null)
return;
gridView.setAdapter(mImages);
gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
ImageAdapter adapter = (ImageAdapter) parent.getAdapter();
Movie movie = adapter.getItem(position);
if (movie == null)
return;
//intent to be launched
Intent intent = new Intent(getActivity(),DetailActivity.class);
intent.putExtra(Movie.EXTRA_MOVIE,movie.toBundle());
getActivity().startActivity(intent);
}
});
gridView.setOnScrollListener(new AbsListView.OnScrollListener() {
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
int lastScreen = firstVisibleItem + visibleItemCount;
if(lastScreen == totalItemCount)
startLoading();
}
});
}
private class FetchPageTask extends AsyncTask<Integer,Void,Collection<Movie>> {
public final String LOG_TAG = FetchPageTask.class.getSimpleName();
#Override
protected Collection<Movie> doInBackground(Integer... params) {
if (params.length == 0)
return null;
int page = params[0];
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
String responseJsonStr = null;
try {
final String API_BASE_URL = "http://api.themoviedb.org/3/movie/";
final String API_PARAM_PAGE = "page";
final String API_PARAM_KEY = "api_key";
final String API_SORTING = sharedPrefs.getString(getString(R.string.pref_sorting_key),getString(R.string.pref_sorting_default_value));
Uri builtUri = Uri.parse(API_BASE_URL).buildUpon()
.appendPath(API_SORTING)
.appendQueryParameter(API_PARAM_PAGE, String.valueOf(page))
.appendQueryParameter(API_PARAM_KEY, getString(R.string.my_api_key))
.build();
Log.d(LOG_TAG, "Query URI: " + builtUri.toString());
URL url = new URL(builtUri.toString());
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null)
return null;
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null)
buffer.append(line + "\n");
if (buffer.length() == 0)
return null;
responseJsonStr = buffer.toString();
} catch (Exception e) {
Log.e(LOG_TAG, "Error", e);
return null;
} finally {
if (urlConnection != null)
urlConnection.disconnect();
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
Log.e(LOG_TAG, "Error closing input stream", e);
}
}
}
try {
return fetchMoviesFromJson(responseJsonStr);
} catch (JSONException je) {
Log.d(LOG_TAG, "Can't parse JSON " + responseJsonStr, je);
return null;
}
}
private Collection<Movie> fetchMoviesFromJson(String jsonStr) throws JSONException {
final String KEY_MOVIES = "results";
JSONObject json = new JSONObject(jsonStr);
JSONArray movies = json.getJSONArray(KEY_MOVIES);
ArrayList<Movie> result = new ArrayList<Movie>();
for (int i = 0; i < movies.length(); i++) {
result.add(Movie.getMovieFromJson(movies.getJSONObject(i)));
}
return result;
}
#Override
protected void onPostExecute(Collection<Movie> movies)
{
stopLoading();
mPagesLoaded++;
mImages.addAll(movies);
}
}
}
How can I prevent it from duplicating? How should i handle the change of configuration?

In your onCreate for MainActivity replace this line:
getFragmentManager().beginTransaction().add(R.id.frame_container, new PostersFragment(), POSTERSFRAGMENT_TAG).commit();
to
if (savedInstanceState == null) {
getFragmentManager().beginTransaction().add(R.id.frame_container, new PostersFragment(), POSTERSFRAGMENT_TAG).commit();
}
EDIT: Sorry, I didn't clarify as to why this is required. The purpose of this check is to see if the fragment is already there. When can we confirm that the fragment is not there? When savedInstanceState is null.
Initially, the Bundle is null when the activity is first created. When the device has a configuration change, all activities/fragments are destroyed and recreated, excepting the ones on which setRetainInstance(true) has been called. These fragments are not destroyed. They are just attached to the new activity…
When the activity is recreated after the configuration change, the instance of the retained fragment is already present, and the savedInstanceState is not null as a result of this. Hence, you check if savedInstanceState == null and only then proceed to add the fragment to avoid duplicated.