Develop Reference

Why the middle tab of viewPager never call onCreateView for itself?

For the 2 last days I spent all my time to try to find a solution to a strange problem in a viewpager with fragment. All fragment contains a listview (which has his own adapter).
Here is the situation :
I have an activity which instantiate a viewpager and an adapter for it and contains the object adapter class.
public class SellerActivity extends AppCompatActivity {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
private FirebaseAuth mAuth = FirebaseAuth.getInstance();
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_seller);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.vpContainer2);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs2);
tabLayout.setupWithViewPager(mViewPager);
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
// This method will be invoked when a new page becomes selected.
#Override
public void onPageSelected(int position) {
mViewPager.setCurrentItem(position);
mSectionsPagerAdapter.getItem(position);
Toast.makeText(SellerActivity.this,
"Selected page position: " + position, Toast.LENGTH_SHORT).show();
}
// This method will be invoked when the current page is scrolled
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// Code goes here
}
// Called when the scroll state changes:
// SCROLL_STATE_IDLE, SCROLL_STATE_DRAGGING, SCROLL_STATE_SETTLING
#Override
public void onPageScrollStateChanged(int state) {
// Code goes here
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_shop, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
Intent i = new Intent(SellerActivity.this, MainActivity.class);
if (id == R.id.action_home) {
startActivity(i);
finish();
return true;
}
if (id == R.id.action_logout) {
mAuth.signOut();
startActivity(i);
finish();
return false;
}
return super.onOptionsItemSelected(item);
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
return SellerFragment.newInstance(position + 1, "1");
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "En Attente";
case 1:
return "En cours";
case 2:
return "Terminées";
}
return null;
}
}
I have then a fragment which looks like this :
public class SellerFragment extends Fragment {
private String title;
private int page;
private AllOrders allOrders;
final List<CommandItemForSeller> orders = new ArrayList<>();
final LinkedHashMap<String, Order> saveOrders = new LinkedHashMap<>();
public SellerFragment(){
}
// newInstance constructor for creating fragment with arguments
public static SellerFragment newInstance(int page, String title) {
SellerFragment fragmentFirst = new SellerFragment();
Bundle args = new Bundle();
args.putInt("someInt", page);
args.putString("someTitle", title);
fragmentFirst.setArguments(args);
return fragmentFirst;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
page = getArguments().getInt("someInt", 0);
title = getArguments().getString("someTitle");
allOrders = new AllOrders();
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_seller, container, false);
TextView tvLabel = (TextView) view.findViewById(R.id.tvLabel);
tvLabel.setText(page + " -- " + title);
DatabaseReference myRef = FirebaseDatabase.getInstance().getReference().child("orders");
ChildEventListener childEventListener = new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
for (DataSnapshot orders : dataSnapshot.getChildren()) {
String orderString = orders.getValue(String.class);
//allOrders.addOrder(new Order(orderString, orders.getKey().substring(orders.getKey().length() - 4, orders.getKey().length())));
saveOrders.put(orders.getKey(), new Order(orderString, orders.getKey().substring(orders.getKey().length() - 4, orders.getKey().length())));
}
}
#Override
public void onChildChanged (DataSnapshot dataSnapshot, String s){
}
#Override
public void onChildRemoved (DataSnapshot dataSnapshot){
}
#Override
public void onChildMoved (DataSnapshot dataSnapshot, String s){
}
#Override
public void onCancelled (DatabaseError databaseError){
}
};
myRef.addChildEventListener(childEventListener);
orders.clear();
allOrders.clear();
allOrders.addAllOrders(saveOrders.values());
List<Order> selectedOrders = allOrders.getItemsOrderedByStatus(page);
for (int i = 0; i < selectedOrders.size(); i++) {
orders.add(new CommandItemForSeller(selectedOrders.get(i)));
}
CommandItemForSellerAdapter aa = new CommandItemForSellerAdapter(getActivity(), R.layout.pending_listview_item, orders);
ListView lv = (ListView) view.findViewById(R.id.commandListView);
lv.setAdapter(aa);
return view;
}
As you can see each fragment calls content from Firebase Database so it remains asynchronous.
My problem is :
When I try to load "synchronous" data (that I previsouly write in my code), list content is set by onCreate method at the first creation so each fragment for each tab get some content. However, the second tab never ever refresh for new data.
So in a case of asynchronous, onCreate method doesn't return any data (due to the load time) and new datas should be added by the onCreateView (like a refresh) but for the second tab it never happens !
After many hours of debugging, I've just found out the following :
When I switch from tab 1 to tab 2, fragment is rendered for tab 3. When I switch from tab 3 to tab 2, fragment is rendered for tab 1. Even if the getItem(position) returns the right position for the tab, tab 2 now never calls onCreateView method and remains empty.
Please.. tell me why this projet behaves like that, I don't want to give up but I really don't understand what is the issue here.
If you need more specific information, tell me I can give you anything you want.

When using FragmentPagerAdapter, ViewPager keeps adjacent pages "alive" (one to the left and one to the right) - meaning that when you have three fragments only, the second one will be never destroyed. You have to find a different way if you want to refresh data when fragments come into view - one idea is to add listener for page changes, using ViewPager.addOnPageChangeListener method - https://developer.android.com/reference/android/support/v4/view/ViewPager.html#addOnPageChangeListener(android.support.v4.view.ViewPager.OnPageChangeListener)
Then, you can trigger refresh from within onPageSelected callback.
In your case, I think the simplest solution is to make SectionsPagerAdapter implement ViewPager.OnPageChangeListener, store reference to each created Fragment (preferably WeakReference), and then call some refresh method on an appropriate SellerFragment instance.

Android update data fragment

It will be like 3 hours I try to update data from a activity to a fragment. I check all pages but it didn't work...
I have to made a BookManager. I have create some class to do it.
I have a main activity with two fragment, a first empty for the moment and a second with the summary of my list of book (most price of book, average...). When I want to add a book, I use a new activity and take data back after add the book (its work).
and I want to refresh the fragment after add the book.
Code of my main activity :
public class MainActivity extends AppCompatActivity {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
private SimpleBookManager bookManager;
public final static int ADD_BOOK_REQUEST = 1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bookManager = new SimpleBookManager();
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.button_add_menu) {
Intent intent = new Intent(MainActivity.this, AddBookActivity.class);
startActivityForResult(intent, ADD_BOOK_REQUEST);
return true;
}
return super.onOptionsItemSelected(item);
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == ADD_BOOK_REQUEST) {
// On vérifie aussi que l'opération s'est bien déroulée
if (resultCode == RESULT_OK) {
// On affiche le bouton qui a été choisi
String[] valueBook = data.getStringArrayExtra("VALUE");
Book book = this.bookManager.createBook();
book.setTitle(valueBook[0]);
book.setAuthor(valueBook[1]);
book.setCourse(valueBook[2]);
book.setIsbm(valueBook[3]);
book.setPrice((int) Integer.parseInt(valueBook[4]));
}
}
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
switch (position) {
case 0:
return PlaceholderFragment.newInstance(position + 1);
case 1:
Fragment frag = SummaryFragment.newInstance(bookManager);
return frag;
}
return PlaceholderFragment.newInstance(position + 1);
}
#Override
public int getCount() {
// Show 2 total pages.
return 2;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "COLLECTION";
case 1:
return "SUMMARY";
}
return null;
}
}
In the method onActivityResult, I add the book and I want here to refresh or eventuelly when I'm back to the summary fragment. I tried with a FragmentTransaction, but the commit didn't work, because I don't have a tag to get my fragment (I don't know how it works to get one)... And the we don't have instance of the fragment because we use a static method to create it.
Code of my fragment :
public class SummaryFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String BOOKMANAGER = "book";
// TODO: Rename and change types of parameters
private String[] info;
private OnFragmentInteractionListener mListener;
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #return A new instance of fragment SummaryFragment.
*/
// TODO: Rename and change types and number of parameters
public static SummaryFragment newInstance(SimpleBookManager bookManager) {
String[] info = new String[5];
info[0] = String.valueOf(bookManager.count());
info[1] = String.valueOf(bookManager.getTotalCost());
info[2] = String.valueOf(bookManager.getMaxPrice());
info[3] = String.valueOf(bookManager.getMinPrice());
info[4] = String.valueOf(bookManager.getMeanPrice());
SummaryFragment fragment = new SummaryFragment();
Bundle args = new Bundle();
args.putStringArray(BOOKMANAGER, info);
fragment.setArguments(args);
return fragment;
}
public SummaryFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
this.info = getArguments().getStringArray(BOOKMANAGER);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView;
TextView textView;
rootView = inflater.inflate(R.layout.fragment_summary, container, false);
textView = (TextView) rootView.findViewById(R.id.nbbook_value);
textView.setText(this.info[0]);
textView = (TextView) rootView.findViewById(R.id.totalcost_value);
textView.setText(this.info[1] + " SEK");
textView = (TextView) rootView.findViewById(R.id.mostprice_value);
textView.setText(this.info[2] + " SEK");
textView = (TextView) rootView.findViewById(R.id.leastprice_value);
textView.setText(this.info[3] + " SEK");
textView = (TextView) rootView.findViewById(R.id.averageprice_value);
textView.setText(this.info[4] + " SEK");
return rootView;
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
Activity a;
if (context instanceof Activity){
a=(Activity) context;
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onFragmentInteraction(Uri uri);
}
}

You can get the Fragment instance by calling FragmentPagerAdapter's getItem method.
SummaryFragment frag = (SummaryFragment) mSectionsPagerAdapter.getItem(1);
And then call a method in the Fragment instance to refresh display, make sure to check null before calling method on the Fragment.
if (frag != null) {
frag.refreshBook(book);
}

Multiple actionbar master/detail (one for master and one for detail)

I'm trying to create an application using the Master/Detail Flow template provided by Android.
I'm trying to add multiple actionbar menu items to both the master and detail portions of the actionbar.
I have use the example of Android studio but when i set the different menu for master e for detail, is show only the menu (to right) .
the Activity detail is:
public class PDetailActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_p_detail);
// Show the Up button in the action bar.
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// savedInstanceState is non-null when there is fragment state
// saved from previous configurations of this activity
// (e.g. when rotating the screen from portrait to landscape).
// In this case, the fragment will automatically be re-added
// to its container so we don't need to manually add it.
// For more information, see the Fragments API guide at:
//
// http://developer.android.com/guide/components/fragments.html
//
if (savedInstanceState == null) {
// Create the detail fragment and add it to the activity
// using a fragment transaction.
Bundle arguments = new Bundle();
arguments.putString(PDetailFragment.ARG_ITEM_ID, getIntent().getStringExtra(PatientDetailFragment.ARG_ITEM_ID));
PatientDetailFragment fragment = new PDetailFragment();
fragment.setArguments(arguments);
getSupportFragmentManager().beginTransaction().add(R.id.p_detail_container, fragment).commit();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_p_detail, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
navigateUpTo(new Intent(this, PListActivity.class));
return true;
}
return super.onOptionsItemSelected(item);
}
}
the fragment detail is:
public class PDetailFragment extends Fragment {
/**
* The fragment argument representing the item ID that this fragment
* represents.
*/
public static final String ARG_ITEM_ID = "item_id";
/**
* The dummy content this fragment is presenting.
*/
private PObj mItem;
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public PDetailFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
((PatientDetailActivity)getActivity()).getSupportActionBar().setTitle("Detail");
if (getArguments().containsKey(ARG_ITEM_ID)) {
// Load the dummy content specified by the fragment
// arguments. In a real-world scenario, use a Loader
// to load content from a content provider.
mItem = PListFragment.pObjHashMap.get(getArguments().getString(ARG_ITEM_ID));
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_p_detail, container, false);
// Show the dummy content as text in a TextView.
if (mItem != null) {
((TextView) rootView.findViewById(R.id.p_detail)).setText(mItem.name);
}
return rootView;
}
}
The activity master:
public class PListActivity extends BaseActivity implements PListFragment.Callbacks {
/**
* Whether or not the activity is in two-pane mode, i.e. running on a tablet
* device.
*/
private boolean mTwoPane;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_p_list);
// Show the Up button in the action bar.
// getActionBar().setDisplayHomeAsUpEnabled(true);
if (findViewById(R.id.p_detail_container) != null) {
// The detail container view will be present only in the
// large-screen layouts (res/values-large and
// res/values-sw600dp). If this view is present, then the
// activity should be in two-pane mode.
mTwoPane = true;
// In two-pane mode, list items should be given the
// 'activated' state when touched.
((PListFragment) getSupportFragmentManager()
.findFragmentById(R.id.p_list))
.setActivateOnItemClick(true);
}
// TODO: If exposing deep links into your app, handle intents here.
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_p, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. Use NavUtils to allow users
// to navigate up one level in the application structure. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
// navigateUpFromSameTask(this);
SharedPreferenceObj sp = MySharedPref.getSharedPref(getApplicationContext());
sp.setLast_id_office(StaticValues.ID);
MySharedPref.setSharedPref(getApplicationContext(), sp);
finish();
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Callback method from {#link PListFragment.Callbacks}
* indicating that the item with the given ID was selected.
*/
#Override
public void onItemSelected(String id) {
if (mTwoPane) {
// In two-pane mode, show the detail view in this activity by
// adding or replacing the detail fragment using a
// fragment transaction.
Bundle arguments = new Bundle();
arguments.putString(PatientDetailFragment.ARG_ITEM_ID, id);
PatientDetailFragment fragment = new PDetailFragment();
fragment.setArguments(arguments);
getSupportFragmentManager().beginTransaction()
.replace(R.id.p_detail_container, fragment)
.commit();
} else {
// In single-pane mode, simply start the detail activity
// for the selected item ID.
Intent dIntent = new Intent(this, PDetailActivity.class);
dIntent.putExtra(PDetailFragment.ARG_ITEM_ID, id);
startActivity(dIntent);
}
}
#Override
public void onBackPressed() {
SharedPreferenceObj sp = MySharedPref.getSharedPref(getApplicationContext());
sp.setLast_id_office(StaticValues.ID);
MySharedPref.setSharedPref(getApplicationContext(),sp);
super.onBackPressed();
}
}
the fragment master is:
public class PListFragment extends ListFragment {
//DummyContent dummyContent ;
public static List<PObj> pObjArrayList = new ArrayList<PObj>();
public static Map<String, PObj> pObjHashMap = new HashMap<String, PObj>();
/**
* The serialization (saved instance state) Bundle key representing the
* activated item position. Only used on tablets.
*/
private static final String STATE_ACTIVATED_POSITION = "activated_position";
/**
* The fragment's current callback object, which is notified of list item
* clicks.
*/
private Callbacks mCallbacks = sDummyCallbacks;
/**
* The current activated item position. Only used on tablets.
*/
private int mActivatedPosition = ListView.INVALID_POSITION;
/**
* A callback interface that all activities containing this fragment must
* implement. This mechanism allows activities to be notified of item
* selections.
*/
public interface Callbacks {
/**
* Callback for when an item has been selected.
*/
public void onItemSelected(String id);
}
/**
* A dummy implementation of the {#link Callbacks} interface that does
* nothing. Used only when this fragment is not attached to an activity.
*/
private static Callbacks sDummyCallbacks = new Callbacks() {
#Override
public void onItemSelected(String id) {
}
};
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public PListFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
((PListActivity)getActivity()).getSupportActionBar().setTitle("Master");
pObjArrayList.clear();
pObjHashMap.clear();
for (int i=0;i<10;i++) {
patientObjArrayList.add(new PObj(i+"","name"+i,"address"+i));
patientObjHashMap.put(i+"",new PObj(i+"","name"+i,"address"+i));
}
setListAdapter(new ArrayAdapter<PObj>(getActivity(), android.R.layout.simple_list_item_activated_1,
android.R.id.text1, patientObjArrayList));
// TODO: replace with a real list adapter.
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Restore the previously serialized activated item position.
if (savedInstanceState != null
&& savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
Activity activity = (Activity) context;
// Activities containing this fragment must implement its callbacks.
if (!(activity instanceof Callbacks)) {
throw new IllegalStateException("Activity must implement fragment's callbacks.");
}
mCallbacks = (Callbacks) activity;
}
#Override
public void onDetach() {
super.onDetach();
// Reset the active callbacks interface to the dummy implementation.
mCallbacks = sDummyCallbacks;
}
#Override
public void onListItemClick(ListView listView, View view, int position, long id) {
super.onListItemClick(listView, view, position, id);
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mCallbacks.onItemSelected(pObjArrayList.get(position).id);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (mActivatedPosition != ListView.INVALID_POSITION) {
// Serialize and persist the activated item position.
outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
}
}
/**
* Turns on activate-on-click mode. When this mode is on, list items will be
* given the 'activated' state when touched.
*/
public void setActivateOnItemClick(boolean activateOnItemClick) {
// When setting CHOICE_MODE_SINGLE, ListView will automatically
// give items the 'activated' state when touched.
getListView().setChoiceMode(activateOnItemClick
? ListView.CHOICE_MODE_SINGLE
: ListView.CHOICE_MODE_NONE);
}
private void setActivatedPosition(int position) {
if (position == ListView.INVALID_POSITION) {
getListView().setItemChecked(mActivatedPosition, false);
} else {
getListView().setItemChecked(position, true);
}
mActivatedPosition = position;
}
}
The problem is that i show only one menu (master) and no the menu (detail)
in this screenshot
in this screenshot I have only one menu and the + is on the right instead of the left next to the title "Master".
In the part relating to the detail is missing from the title and even the symbol X.
how can fix my problem?

LongClick to Delete List Item (Using Fragments in Master-Detail)

I've created a Master-Detail Flow application, and I'm using all of the default files that Eclipse/Android creates. I created a project using the template, and haven't modified anything in it, except to add the methods discussed below for deleting the item.
I need to implement an onItemLongClickListener so that when I longpress an item in the list, that item is deleted. I don't want an alert or a confirmation or to select multiple items, I just want the one I longclick to go away.
I've found several tutorials on the subject, but my issue is that they aren't using fragments, so I'm getting a bit confused about what methods go where. (This is the one I'm mostly working with: AndroidForBeginners)
If I'm understanding correctly, I should only be using the ItemListActivity and ItemListFragment. I understand that methods in the Fragment will be called in the Activity (such as the default onItemSelected that comes with the template). I understand that the removeItemFromList method (from the linked tutorial) removes the item from the array and notifies the adapter to update the list. My problem is, I don't know where the array and adapter are within the Master-Detail fragments and activities. There's an ArrayList in the DummyContent, so I thought maybe if I call removeItem in the fragment, then send it to the Activity, then call it from the DummyContent class it would work. But it doesn't, and I'm stuck.
Any advice would be much appreciated!
As requested, here is the code I'm currently using. As I said, just the default android template.
ItemListActivity.java
package Andrea.deletelistitem;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
/**
* An activity representing a list of Items. This activity
* has different presentations for handset and tablet-size devices. On
* handsets, the activity presents a list of items, which when touched,
* lead to a {#link ItemDetailActivity} representing
* item details. On tablets, the activity presents the list of items and
* item details side-by-side using two vertical panes.
* <p>
* The activity makes heavy use of fragments. The list of items is a
* {#link ItemListFragment} and the item details
* (if present) is a {#link ItemDetailFragment}.
* <p>
* This activity also implements the required
* {#link ItemListFragment.Callbacks} interface
* to listen for item selections.
*/
public class ItemListActivity extends FragmentActivity
implements ItemListFragment.Callbacks {
/**
* Whether or not the activity is in two-pane mode, i.e. running on a tablet
* device.
*/
private boolean mTwoPane;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item_list);
if (findViewById(R.id.item_detail_container) != null) {
// The detail container view will be present only in the
// large-screen layouts (res/values-large and
// res/values-sw600dp). If this view is present, then the
// activity should be in two-pane mode.
mTwoPane = true;
// In two-pane mode, list items should be given the
// 'activated' state when touched.
((ItemListFragment) getSupportFragmentManager()
.findFragmentById(R.id.item_list))
.setActivateOnItemClick(true);
}
// TODO: If exposing deep links into your app, handle intents here.
}
/**
* Callback method from {#link ItemListFragment.Callbacks}
* indicating that the item with the given ID was selected.
*/
#Override
public void onItemSelected(String id) {
if (mTwoPane) {
// In two-pane mode, show the detail view in this activity by
// adding or replacing the detail fragment using a
// fragment transaction.
Bundle arguments = new Bundle();
arguments.putString(ItemDetailFragment.ARG_ITEM_ID, id);
ItemDetailFragment fragment = new ItemDetailFragment();
fragment.setArguments(arguments);
getSupportFragmentManager().beginTransaction()
.replace(R.id.item_detail_container, fragment)
.commit();
} else {
// In single-pane mode, simply start the detail activity
// for the selected item ID.
Intent detailIntent = new Intent(this, ItemDetailActivity.class);
detailIntent.putExtra(ItemDetailFragment.ARG_ITEM_ID, id);
startActivity(detailIntent);
}
}
}
ItemListFragment.java
package Andrea.deletelistitem;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import Andrea.deletelistitem.dummy.DummyContent;
/**
* A list fragment representing a list of Items. This fragment
* also supports tablet devices by allowing list items to be given an
* 'activated' state upon selection. This helps indicate which item is
* currently being viewed in a {#link ItemDetailFragment}.
* <p>
* Activities containing this fragment MUST implement the {#link Callbacks}
* interface.
*/
public class ItemListFragment extends ListFragment {
/**
* The serialization (saved instance state) Bundle key representing the
* activated item position. Only used on tablets.
*/
private static final String STATE_ACTIVATED_POSITION = "activated_position";
/**
* The fragment's current callback object, which is notified of list item
* clicks.
*/
private Callbacks mCallbacks = sDummyCallbacks;
/**
* The current activated item position. Only used on tablets.
*/
private int mActivatedPosition = ListView.INVALID_POSITION;
/**
* A callback interface that all activities containing this fragment must
* implement. This mechanism allows activities to be notified of item
* selections.
*/
public interface Callbacks {
/**
* Callback for when an item has been selected.
*/
public void onItemSelected(String id);
}
/**
* A dummy implementation of the {#link Callbacks} interface that does
* nothing. Used only when this fragment is not attached to an activity.
*/
private static Callbacks sDummyCallbacks = new Callbacks() {
#Override
public void onItemSelected(String id) {
}
};
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public ItemListFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// TODO: replace with a real list adapter.
setListAdapter(new ArrayAdapter<DummyContent.DummyItem>(
getActivity(),
android.R.layout.simple_list_item_activated_1,
android.R.id.text1,
DummyContent.ITEMS));
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Restore the previously serialized activated item position.
if (savedInstanceState != null
&& savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
}
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// Activities containing this fragment must implement its callbacks.
if (!(activity instanceof Callbacks)) {
throw new IllegalStateException("Activity must implement fragment's callbacks.");
}
mCallbacks = (Callbacks) activity;
}
#Override
public void onDetach() {
super.onDetach();
// Reset the active callbacks interface to the dummy implementation.
mCallbacks = sDummyCallbacks;
}
#Override
public void onListItemClick(ListView listView, View view, int position, long id) {
super.onListItemClick(listView, view, position, id);
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mCallbacks.onItemSelected(DummyContent.ITEMS.get(position).id);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (mActivatedPosition != ListView.INVALID_POSITION) {
// Serialize and persist the activated item position.
outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
}
}
/**
* Turns on activate-on-click mode. When this mode is on, list items will be
* given the 'activated' state when touched.
*/
public void setActivateOnItemClick(boolean activateOnItemClick) {
// When setting CHOICE_MODE_SINGLE, ListView will automatically
// give items the 'activated' state when touched.
getListView().setChoiceMode(activateOnItemClick
? ListView.CHOICE_MODE_SINGLE
: ListView.CHOICE_MODE_NONE);
}
private void setActivatedPosition(int position) {
if (position == ListView.INVALID_POSITION) {
getListView().setItemChecked(mActivatedPosition, false);
} else {
getListView().setItemChecked(position, true);
}
mActivatedPosition = position;
}
}
DummyContent.java
package Andrea.deletelistitem.dummy;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Helper class for providing sample content for user interfaces created by
* Android template wizards.
* <p>
* TODO: Replace all uses of this class before publishing your app.
*/
public class DummyContent {
/**
* An array of sample (dummy) items.
*/
public static List<DummyItem> ITEMS = new ArrayList<DummyItem>();
/**
* A map of sample (dummy) items, by ID.
*/
public static Map<String, DummyItem> ITEM_MAP = new HashMap<String, DummyItem>();
static {
// Add 3 sample items.
addItem(new DummyItem("1", "Item 1"));
addItem(new DummyItem("2", "Item 2"));
addItem(new DummyItem("3", "Item 3"));
}
private static void addItem(DummyItem item) {
ITEMS.add(item);
ITEM_MAP.put(item.id, item);
}
/**
* A dummy item representing a piece of content.
*/
public static class DummyItem {
public String id;
public String content;
public DummyItem(String id, String content) {
this.id = id;
this.content = content;
}
#Override
public String toString() {
return content;
}
}
}
This is the method from the tutorial:
protected void removeItemFromList(int position) {
final int deletePosition = position;
AlertDialog.Builder alert = new AlertDialog.Builder(
MainActivity.this);
alert.setTitle("Delete");
alert.setMessage("Do you want delete this item?");
alert.setPositiveButton("YES", new OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// TOD O Auto-generated method stub
// main code on after clicking yes
arr.remove(deletePosition);
adapter.notifyDataSetChanged();
adapter.notifyDataSetInvalidated();
}
});
alert.setNegativeButton("CANCEL", new OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
alert.show();
}
This is the method with my modifications, to remove the confirmation alert:
protected void removeItemFromList(int position) {
arr.remove(position);
adapter.notifyDataSetChanged();
adapter.notifyDataSetInvalidated();
}
In this method, I think ITEMS from the DummyContent would replace the arr array, because it's an ArrayList. I'm not sure about the adapter, though.

There's a method on any Fragment called onActivityCreated You want to #Override that method.
Then, inside it, using getListView() you can attach an onLongItemClickListener().
Like so:
getListView().setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
//Here you implement your code. Basically delete an item from
// the underlying data structure of your adapter, and then...
setListAdapter(.....); //re-set the list adapter.
return false;
}
});

How to disable the pinned header feture on the Sticky grid view in android

What i am trying to do ::
I want header for a certain set of rows one after another
What i am using:: Sticky Header( i am running this sample)
What is happening::
Project runs well but when i scroll the header goes and sits on top until the next header comes
Question:: (Disabling pinned header & enable the header scroll along with grid)
I want to disable this feature so that the header scrolls along with
gridview being scrolled instead of waiting for the next header
I have seen this feature possible in expandable listview but how to
implement this here
ItemDetailFragment.java
public class ItemDetailFragment extends Fragment {
/**
* The fragment argument representing the item ID that this fragment
* represents.
*/
public static final String ARG_ITEM_ID = "item_id";
/**
* The dummy content this fragment is presenting.
*/
private int mItem;
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public ItemDetailFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments().containsKey(ARG_ITEM_ID)) {
// Load the dummy content specified by the fragment
// arguments. In a real-world scenario, use a Loader
// to load content from a content provider.
mItem = getArguments().getInt(ARG_ITEM_ID);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_item_detail, container, false);
((TextView) rootView.findViewById(R.id.item_detail)).setText(getResources().getStringArray(R.array.countries)[mItem]);
return rootView;
}
}
ItemListActivity.java
public class ItemListActivity extends ActionBarActivity implements ItemListFragment.Callbacks {
/**
* Whether or not the activity is in two-pane mode, i.e. running on a tablet
* device.
*/
private boolean mTwoPane;
/**
* Callback method from {#link ItemListFragment.Callbacks} indicating that
* the item with the given ID was selected.
*/
#Override
public void onItemSelected(int id) {
if (mTwoPane) {
// In two-pane mode, show the detail view in this activity by
// adding or replacing the detail fragment using a
// fragment transaction.
Bundle arguments = new Bundle();
arguments.putInt(ItemDetailFragment.ARG_ITEM_ID, id);
ItemDetailFragment fragment = new ItemDetailFragment();
fragment.setArguments(arguments);
getSupportFragmentManager().beginTransaction()
.replace(R.id.item_detail_container, fragment)
.commit();
} else {
// In single-pane mode, simply start the detail activity
// for the selected item ID.
Intent detailIntent = new Intent(this, ItemDetailActivity.class);
detailIntent.putExtra(ItemDetailFragment.ARG_ITEM_ID, id);
startActivity(detailIntent);
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item_list);
if (findViewById(R.id.item_detail_container) != null) {
// The detail container view will be present only in the
// large-screen layouts (res/values-large and
// res/values-sw600dp). If this view is present, then the
// activity should be in two-pane mode.
mTwoPane = true;
// In two-pane mode, list items should be given the
// 'activated' state when touched.
((ItemListFragment) getSupportFragmentManager().findFragmentById(R.id.item_list)).setActivateOnItemClick(true);
}
// TODO: If exposing deep links into your app, handle intents here.
}
}
ItemListFragment.java
public class ItemListFragment extends Fragment implements OnItemClickListener,
OnHeaderClickListener, OnHeaderLongClickListener {
private static final String KEY_LIST_POSITION = "key_list_position";
/**
* A dummy implementation of the {#link Callbacks} interface that does
* nothing. Used only when this fragment is not attached to an activity.
*/
private static Callbacks sDummyCallbacks = new Callbacks() {
#Override
public void onItemSelected(int id) {
}
};
/**
* The serialization (saved instance state) Bundle key representing the
* activated item position. Only used on tablets.
*/
private static final String STATE_ACTIVATED_POSITION = "activated_position";
/**
* The current activated item position. Only used on tablets.
*/
private int mActivatedPosition = ListView.INVALID_POSITION;
/**
* The fragment's current callback object, which is notified of list item
* clicks.
*/
private Callbacks mCallbacks = sDummyCallbacks;
private int mFirstVisible;
private GridView mGridView;
private Menu mMenu;
private Toast mToast;
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public ItemListFragment() {
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// Activities containing this fragment must implement its callbacks.
if (!(activity instanceof Callbacks)) {
throw new IllegalStateException("Activity must implement fragment's callbacks.");
}
mCallbacks = (Callbacks)activity;
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.fragment_item_list, menu);
mMenu = menu;
menu.findItem(R.id.menu_toggle_sticky).setChecked(
((StickyGridHeadersGridView)mGridView).areHeadersSticky());
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_item_grid, container, false);
}
#Override
public void onDetach() {
super.onDetach();
// Reset the active callbacks interface to the dummy implementation.
mCallbacks = sDummyCallbacks;
}
#Override
public void onHeaderClick(AdapterView<?> parent, View view, long id) {
String text = "Header " + ((TextView)view.findViewById(android.R.id.text1)).getText() + " was tapped.";
if (mToast == null) {
mToast = Toast.makeText(getActivity(), text, Toast.LENGTH_SHORT);
} else {
mToast.setText(text);
}
mToast.show();
}
#Override
public boolean onHeaderLongClick(AdapterView<?> parent, View view, long id) {
String text = "Header " + ((TextView)view.findViewById(android.R.id.text1)).getText() + " was long pressed.";
if (mToast == null) {
mToast = Toast.makeText(getActivity(), text, Toast.LENGTH_SHORT);
} else {
mToast.setText(text);
}
mToast.show();
return true;
}
#Override
public void onItemClick(AdapterView<?> gridView, View view, int position, long id) {
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mCallbacks.onItemSelected(position);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_toggle_sticky:
item.setChecked(!item.isChecked());
((StickyGridHeadersGridView)mGridView)
.setAreHeadersSticky(!((StickyGridHeadersGridView)mGridView)
.areHeadersSticky());
return true;
case R.id.menu_use_list_adapter:
mGridView.setAdapter(new ArrayAdapter<String>(getActivity(), R.layout.item,
getResources().getStringArray(R.array.countries)));
mMenu.findItem(R.id.menu_use_list_adapter).setVisible(false);
mMenu.findItem(R.id.menu_use_sticky_adapter).setVisible(true);
mMenu.findItem(R.id.menu_toggle_sticky).setVisible(false);
return true;
case R.id.menu_use_sticky_adapter:
mGridView.setAdapter(new StickyGridHeadersSimpleArrayAdapter<String>(getActivity()
.getApplicationContext(), getResources().getStringArray(R.array.countries),
R.layout.header, R.layout.item));
mMenu.findItem(R.id.menu_use_list_adapter).setVisible(true);
mMenu.findItem(R.id.menu_toggle_sticky).setVisible(true);
mMenu.findItem(R.id.menu_use_sticky_adapter).setVisible(false);
return true;
default:
break;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (mActivatedPosition != ListView.INVALID_POSITION) {
// Serialize and persist the activated item position.
outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
}
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mGridView = (GridView)view.findViewById(R.id.asset_grid);
mGridView.setOnItemClickListener(this);
/*
* Currently set in the XML layout, but this is how you would do it in
* your code.
*/
// mGridView.setColumnWidth((int) calculatePixelsFromDips(100));
// mGridView.setNumColumns(StickyGridHeadersGridView.AUTO_FIT);
mGridView.setAdapter(new StickyGridHeadersSimpleArrayAdapter<String>(getActivity()
.getApplicationContext(), getResources().getStringArray(R.array.countries),
R.layout.header, R.layout.item));
if (savedInstanceState != null) {
mFirstVisible = savedInstanceState.getInt(KEY_LIST_POSITION);
}
mGridView.setSelection(mFirstVisible);
// Restore the previously serialized activated item position.
if (savedInstanceState != null && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
}
((StickyGridHeadersGridView)mGridView).setOnHeaderClickListener(this);
((StickyGridHeadersGridView)mGridView).setOnHeaderLongClickListener(this);
setHasOptionsMenu(true);
}
/**
* Turns on activate-on-click mode. When this mode is on, list items will be
* given the 'activated' state when touched.
*/
#TargetApi(Build.VERSION_CODES.HONEYCOMB)
public void setActivateOnItemClick(boolean activateOnItemClick) {
// When setting CHOICE_MODE_SINGLE, ListView will automatically
// give items the 'activated' state when touched.
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
mGridView.setChoiceMode(activateOnItemClick ? ListView.CHOICE_MODE_SINGLE
: ListView.CHOICE_MODE_NONE);
}
}
#SuppressLint("NewApi")
private void setActivatedPosition(int position) {
if (position == ListView.INVALID_POSITION) {
mGridView.setItemChecked(mActivatedPosition, false);
} else {
mGridView.setItemChecked(position, true);
}
mActivatedPosition = position;
}
/**
* A callback interface that all activities containing this fragment must
* implement. This mechanism allows activities to be notified of item
* selections.
*/
public interface Callbacks {
/**
* Callback for when an item has been selected.
*/
public void onItemSelected(int position);
}
}
ItemDetailActivity.java
public class ItemDetailActivity extends ActionBarActivity {
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. Use NavUtils to allow users
// to navigate up one level in the application structure. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
NavUtils.navigateUpTo(this, new Intent(this, ItemListActivity.class));
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item_detail);
// Show the Up button in the action bar.
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// savedInstanceState is non-null when there is fragment state
// saved from previous configurations of this activity
// (e.g. when rotating the screen from portrait to landscape).
// In this case, the fragment will automatically be re-added
// to its container so we don't need to manually add it.
// For more information, see the Fragments API guide at:
//
// http://developer.android.com/guide/components/fragments.html
//
if (savedInstanceState == null) {
// Create the detail fragment and add it to the activity
// using a fragment transaction.
Bundle arguments = new Bundle();
arguments.putInt(ItemDetailFragment.ARG_ITEM_ID,
getIntent().getIntExtra(ItemDetailFragment.ARG_ITEM_ID, 0));
ItemDetailFragment fragment = new ItemDetailFragment();
fragment.setArguments(arguments);
getSupportFragmentManager().beginTransaction()
.add(R.id.item_detail_container, fragment).commit();
}
}
}

You can make the headers scroll with your view by adding the following to your code:
mGridView.setAreHeadersSticky(false);
Hope this helps.