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How to keep track of data changes across Fragments?

I have an app, where I have one Activity (main), and there in the layout, I have a ViewPager2. That ViewPager2's adapter is set with 2 fragments. Let's call one of these as Fragment A.
When Fragment A opens up, users have the option to open another fragment, Fragment B from within itself. (by transaction; I have an empty FrameLayout inside Fragment A). Fragment B provides a dialog box to edit the data shown with a RecyclerView in Fragment A. Fragment A itself also has a few options to change the data in its RecyclerView.
This data is populated from Shared preferences. Now, here's the problem - since the Fragments can be made to communicate only with the Activity with Interfaces, I can save the data in the Activity, but then I have no other option but to reload the entire RecyclerView in Fragment A since Fragment A doesn't know at which position it got the new data.
Please advice. Below are the Fragments and the Activity that I mentioned.
MainActivity.java:
package com.coffeetech.kittycatch;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.viewpager2.widget.ViewPager2;
import android.os.Bundle;
import com.google.android.material.tabs.TabLayout;
import com.google.android.material.tabs.TabLayoutMediator;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity implements FoodEditorFragment.SendFoodFromEditor{
ViewPager2 viewPager;
TabLayout tab_menu;
SwipeAdapter adapter;
ArrayList<Food> foods;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager=findViewById(R.id.viewpager);
adapter=new SwipeAdapter(this);
viewPager.setAdapter(adapter);
//SETTING TABS
tab_menu = findViewById(R.id.tab_menu);
new TabLayoutMediator(tab_menu, viewPager, true, new TabLayoutMediator.TabConfigurationStrategy() {
#Override
public void onConfigureTab(#NonNull TabLayout.Tab tab, int position) {
switch(position){
case 0:
tab.setText("INVENTORY");
break;
case 1:
tab.setText("SHOPPING LIST");
}
}
}).attach();
}
#Override
public void onBackPressed() {
super.onBackPressed(); //TODO: CONFIGURE THIS
}
#Override
public void sendFood(Food food, int position) { //TODO: CODE TO REPLACE DATA TO SPECIFIC POSITION
loadData();
saveData();
}
#Override
public void sendFood(Food food) { //TODO: CODE TO ADD DATA TO POSITION 0
loadData();
saveData();
}
public void loadData(){
//TODO: LOAD THE LIST HERE
}
public void saveData(){
//TODO: SAVE THE DATA HERE
}
}
The FragmentStateAdapter for the ViewPager2:
package com.coffeetech.kittycatch;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;
public class SwipeAdapter extends FragmentStateAdapter {
Fragment fragment;
public SwipeAdapter(FragmentActivity fa){
super(fa);
}
#NonNull
#Override
public Fragment createFragment(int position) {
switch (position){
case 0: //START INVENTORY FRAGMENT
fragment = new InventoryFragment();
break;
case 1: //START SHOPPING LIST FRAGMENT
fragment = new ShoppingListFragment();
break;
}
return fragment;
}
#Override
public int getItemCount() {
return 2;
}
}
Fragment 'A':
package com.coffeetech.kittycatch;
import android.content.Context;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.Toast;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import java.util.ArrayList;
public class InventoryFragment extends Fragment {
//GLOBAL VARIABLES
RecyclerView recyclerView;
FoodAdapter foodAdapter;
ArrayList<Food> foods = new ArrayList<Food>();
FloatingActionButton add_button;
FrameLayout frameLayout;
Food food;
int q; //for use in decrease and functions
public InventoryFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public void onPause() { //TODO:CODE TO SAVE DATA
saveData();
super.onPause();
}
#Override
public void onResume() { //TODO:CODE TO LOAD DATA
loadData();
super.onResume();
//food constructor takes arguments -> (String name, int type, int quantity, int min_quantity)
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_inventory, container, false);
foodAdapter = new FoodAdapter(foods);
recyclerView=v.findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(foodAdapter);
//setting up the frameLayout
frameLayout = v.findViewById(R.id.food_editor_frame);
//setting up the Add button
add_button=v.findViewById(R.id.add_button);
add_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) { //for new food addition to list
openFoodEditorFragment();
}
});
foodAdapter.setOnFoodcardClickListener(new FoodAdapter.OnFoodcardClickListener() {
#Override
public void deleteFood(int position) { //code that deletes current food
foods.remove(position);
foodAdapter.notifyItemRemoved(position);
}
#Override
public void onEdit(int position, int mode) { //code that runs the edit of each food, mode=1 for edit
openFoodEditorFragment(position,foods.get(position)); //TODO: SEE IF YOU NEED 'mode' AT ALL
}
#Override
public void decrease(int position) {
food = foods.get(position);
q=food.getQuantity();
food.setQuantity(q-1);
foodAdapter.notifyItemChanged(position);
}
#Override
public void increase(int position) {
food = foods.get(position);
q=food.getQuantity();
food.setQuantity(q+1);
foodAdapter.notifyItemChanged(position);
}
#Override
public void setSeekBar(int position,int progress) {
food = foods.get(position);
food.setQuantity(progress);
Toast.makeText(getContext(),"Quantity set to "+progress+"%",Toast.LENGTH_SHORT).show();
foodAdapter.notifyItemChanged(position);
}
});
return v;
}
public void openFoodEditorFragment(int position,Food food){ //code for Editor in Edit Old mode
//creating new Bundle and passing each member data of 'food'
Bundle bundle = new Bundle();
bundle.putString("name",food.getName());
bundle.putInt("type",food.getType());
bundle.putInt("quantity",food.getQuantity());
bundle.putInt("min_quantity",food.getMin_quantity());
bundle.putInt("mode",1);
bundle.putInt("position",position);
//setting up arguments for Fragment
FoodEditorFragment foodEditorFragment = new FoodEditorFragment();
foodEditorFragment.setArguments(bundle);
//creating the Fragment
FragmentTransaction transaction=getFragmentManager().beginTransaction();
transaction.replace(R.id.food_editor_frame,foodEditorFragment);
transaction.commit();
}
public void openFoodEditorFragment(){ //code for Editor in Add New mode
//creating new Bundle and passing each member data of 'food'
Bundle bundle = new Bundle();
bundle.putInt("position",0);
bundle.putInt("mode",0);
//setting up arguments for Fragment
FoodEditorFragment foodEditorFragment = new FoodEditorFragment();
foodEditorFragment.setArguments(bundle);
//creating the Fragment
FragmentTransaction transaction=getFragmentManager().beginTransaction();
transaction.replace(R.id.food_editor_frame,foodEditorFragment);
transaction.commit();
}
protected void setData(int position, Food food){
foods.remove(position);
foods.add(position,food);
foodAdapter.notifyItemChanged(position);
}
protected void setData(Food food){
foods.add(0,food);
foodAdapter.notifyItemInserted(0);
Toast.makeText(getContext(),"Added to the top",Toast.LENGTH_SHORT).show();
}
void loadData(){
//TODO: CODE TO LOAD DATA
}
void saveData(){
//TODO: CODE TO SAVE DATA
}
}
Fragment 'B':
package com.coffeetech.kittycatch;
import android.content.Context;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
public class FoodEditorFragment extends Fragment {
private TextView name,quantity,min_quantity;
private ImageButton save,cancel;
private RadioGroup radioGroup;
protected int mode,t,position;
protected Food food = new Food();
#Override
public void onAttach(#NonNull Context context) {
super.onAttach(context);
sffe = (SendFoodFromEditor)context;
}
public FoodEditorFragment() {
// Required empty public constructor
}
public interface SendFoodFromEditor{
void sendFood(Food food,int position); //FOR EDITING FOOD
void sendFood(Food food); //FOR NEW FOOD
}
SendFoodFromEditor sffe;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_food_editor, container, false);
name=view.findViewById(R.id.name_editor);
quantity=view.findViewById(R.id.quantity_editor);
min_quantity=view.findViewById(R.id.min_quantity_editor);
save=view.findViewById(R.id.save_button_editor);
cancel=view.findViewById(R.id.cancel_button_editor);
radioGroup=view.findViewById(R.id.radioGroup_editor);
mode=getArguments().getInt("mode");
position=getArguments().getInt("position");
if (mode==1){ //for editing Food
//CODE TO SETUP EDITOR ACCORDING TO INITIAL DETAILS
name.setText(getArguments().getString("name"));
quantity.setText(String.valueOf(getArguments().getInt("quantity")));
min_quantity.setText(String.valueOf(getArguments().getInt("min_quantity")));
t=getArguments().getInt("type");
if(t==0){//for discrete food
radioGroup.check(R.id.discrete_radioButton);
}else{//for cont food
radioGroup.check(R.id.cont_radioButton);
}
}
setButtons();
return view;
}
public void setButtons(){
save.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) { //USE BELOW 'food' TO PASS NEW DATA TO ACTIVITY
try {
if ((!name.getText().toString().isEmpty()) && ((radioGroup.getCheckedRadioButtonId() == R.id.discrete_radioButton) || (radioGroup.getCheckedRadioButtonId() == R.id.cont_radioButton))) {
food.setName(name.getText().toString());
food.setQuantity(Integer.parseInt(quantity.getText().toString()));
food.setMin_quantity(Integer.parseInt(min_quantity.getText().toString()));
if (radioGroup.getCheckedRadioButtonId() == R.id.discrete_radioButton) {
food.setType(0);
} else if (radioGroup.getCheckedRadioButtonId() == R.id.cont_radioButton) {
food.setType(1);
}
//CODE TO SEND THE FOOD TO ACTIVITY
if (mode == 1) {
sffe.sendFood(food, position);
} else {
sffe.sendFood(food);
}
//CLOSE THE FRAGMENT
getFragmentManager().beginTransaction().remove(FoodEditorFragment.this).commit();
} else {
throw new Exception();
}
}catch (Exception e){
Toast.makeText(getContext(),"Please set all details",Toast.LENGTH_SHORT).show();
}
}
});
cancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) { //CODE IF USER PRESSES ON CANCEL
//CLOSE THE FRAGMENT
getFragmentManager().beginTransaction().remove(FoodEditorFragment.this).commit();
}
});
}
}

You need to make following changes.
In Fragment A,
Replace
transaction.replace(R.id.food_editor_frame,foodEditorFragment);
With
transaction.add(R.id.food_editor_frame,foodEditorFragment);
Reason: using replace will remove the fragmentA and FragmentA will always be recreated.
In MainActivity
#Override
public void sendFood(Food food, int position){
//find fragment by Id
Fragment fragmentA = (Fragment)
getSupportFragmentManager().findFragmentById(R.id.fragmetnA);
fragment.setData(position,food)
//code for save data here
}
#Override
public void sendFood(Food food) {
Fragment fragmentA = (Fragment)
getSupportFragmentManager().findFragmentById(R.id.fragmetnA);
fragment.setData(food)
//code for save data here
}

How to create fragment interaction?

These are the imports I have for the fragment class.
import android.os.Bundle;
import android.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
Class being initialized
public class FragmentDemo extends Fragment {
Public constructor is empty and must stay that way
public FragmentDemo() {
}
It must be attached to an activity, the interface depends on said activity
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Inflating layout for fragment
View result = inflater.inflate(R.layout.fragment_fragment_demo, container, false);
TextView textView = (TextView)result.findViewById(R.id.textView2);
Button button = (Button)result.findViewById(R.id.button2);
textView.setText("HEY, THIS IS A TEST!");
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Log.e("FRAGMENT", "BUTTON IS WORKING!");
// why no toast?
}
});
return result;
}
}

You must create two classes to make it more clear, one for the interaction of fragments, and a main class.
The first one should look like this:
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import org.w3c.dom.Text;
/**
* A simple {#link Fragment} subclass.
* Activities that contain this fragment must implement the
* {#link InteractionFragment.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {#link InteractionFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class InteractionFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_NAME = "name";
private static final String ARG_LAST_NAME = "lastName";
// TODO: Rename and change types of parameters
private String name;
private String lastName;
private OnFragmentInteractionListener mListener;
public InteractionFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment InteractionFragment.
*/
// TODO: Rename and change types and number of parameters
// Factory method
public static InteractionFragment newInstance(String param1, String param2) {
InteractionFragment fragment = new InteractionFragment();
Bundle args = new Bundle();
args.putString(ARG_NAME, param1);
args.putString(ARG_LAST_NAME, param2);
fragment.setArguments(args);
return fragment;
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
name = getArguments().getString(ARG_NAME);
lastName = getArguments().getString(ARG_LAST_NAME);
}
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_interaction, container, false);
TextView nameText = (TextView)v.findViewById(R.id.name);
TextView lastNameText = (TextView)v.findViewById(R.id.last_name);
nameText.setText(name);
lastNameText.setText(lastName);
Button button = (Button)v.findViewById(R.id.button3);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
mListener.somethingHappened("THE BUTTON WAS PRESSED, HOW EXCITING!");
}
});
return v;
}
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
public void onDetach() {
super.onDetach();
mListener = null;
}
public void printALog(){
Log.wtf("PRINTING", "ITS WORKING!");
}
/**
* 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 {
void somethingHappened(String message);
}
}
While the second one should look like this:
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.TransactionTooLargeException;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity implements InteractionFragment.OnFragmentInteractionListener {
InteractionFragment fragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
private void addFragment(Fragment f){
// add a fragment through code
// fragment manager - the guy in charge of any fragment related logic
FragmentManager manager = getFragmentManager();
// transactions
FragmentTransaction transaction = manager.beginTransaction();
// actually do the thing
//fragment = InteractionFragment.newInstance("Juan","Perez");
// 3rd parameter - fragment
transaction.add(R.id.container, f, "dude");
transaction.commit();
}
#Override
public void somethingHappened(String message) {
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
public void doSomethingOnFragment(View v){
fragment.printALog();
}
public void swapFragments(View v){
FragmentManager manager = getFragmentManager();
Fragment f = manager.findFragmentByTag("dude");
if(f != null){
Toast.makeText(this, "FRAGMENT BEING REMOVED", Toast.LENGTH_SHORT).show();
FragmentTransaction transaction = manager.beginTransaction();
transaction.remove(f);
transaction.commit();
} else {
Toast.makeText(this, "NO FRAGMENT TO REMOVE", Toast.LENGTH_SHORT).show();
}
}
public void addFragment1(View v){
fragment = InteractionFragment.newInstance("Juan","Perez");
addFragment(fragment);
}
public void addFragment2(View v){
FragmentDemo fd = new FragmentDemo();
addFragment(fd);
}
}

I'm not sure to understand what is your question exactly, so I will assume first that your problem is related to your "Why no toast?" comment.
The thing is you are using the log function, this prints in logcat console, not through toasts.
If you want to display a toast, use
Toast.makeText(context, text, durationInMs).show();
More info here

I'm not sure to understand what is your question exactly, so I will assume first that your problem is related to your "Why no toast?" comment.
The thing is you are using the log function, this prints in logcat console, not through toasts.
If you want to display a toast, use
Toast.makeText(context, text, durationInMs).show();
And because you are in a Fragment the Context used is the activity which has this fragment so to get context we use getActivity(). Hence the Toast will be:
Toast.makeText(getActivity(), text, Toast.LENGTH_SHORT).show();

in viewPager's fragment, recyclerView adapter notifyDataSetChanged not works on first time

I have fragment view pager in activity, that creates a number of pages of entered number before. In each fragment, i have recycler view that needs to update each time user moves to the relevant page. on resume() of each fragment I have getter of data from main activity.
What I am experiencing is while I'm going to next page first time it's not updated, but if after some page movements I would back to it, it is updated, with same resume() code.
I tried some delays after updating the data, it didn't help.
So if before updating data I would check every page it would work as I planned, but if the page was not created before (due to pager adapter) but I still use the same code for updating, it does not work.
I would be glad for some help, stacked on it for 2 days already.
Main Activity:
package com.slavafleer.tipcalculator02;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import com.slavafleer.tipcalculator02.recycler.PageHeaderAdapter;
import java.util.ArrayList;
public class ManualModeActivity extends AppCompatActivity implements
PageHeaderAdapter.Callbacks, DinerFragment.Callbacks {
private int mDinersAmount;
private ViewPager mViewPagerDiners;
private PageHeaderAdapter mHeaderAdapter;
private DinersPagerAdapter mDinersPagerAdapter;
private ArrayList<Order> mOrders;
public ArrayList<Order> getOrders() {
return mOrders;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_manual_mode);
mOrders = new ArrayList<>();
// Get diners amount from previous activity
Intent intent = getIntent();
mDinersAmount = intent.getIntExtra(Constants.KEY_DINNERS_AMOUNT, 1);
// Initialise PageHeader Recycler
mHeaderAdapter = new PageHeaderAdapter(this, mDinersAmount, this);
final RecyclerView recyclerPageHeader = (RecyclerView) findViewById(R.id.recyclerViewPagerHeader);
final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
recyclerPageHeader.setLayoutManager(linearLayoutManager);
recyclerPageHeader.setAdapter(mHeaderAdapter);
// Initialise ViewPager
mViewPagerDiners = (ViewPager) findViewById(R.id.viewPagerDiners);
FragmentManager fragmentManager = getSupportFragmentManager();
mDinersPagerAdapter = new DinersPagerAdapter(fragmentManager, mDinersAmount);
mViewPagerDiners.setAdapter(mDinersPagerAdapter);
// ViewPager Listener - synchronise with headers recycler
mViewPagerDiners.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
// Gets position for selected page
#Override
public void onPageSelected(int position) {
mHeaderAdapter.selectItem(position);
linearLayoutManager.smoothScrollToPosition(recyclerPageHeader, null,position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
}
// HeaderPage Adapter Callbacks
// Scroll ViewPager by clicked Header
#Override
public void onItemClick(int position) {
mViewPagerDiners.setCurrentItem(position, true);
}
// DinerFragment.OrderDialog.Callbacks
// Send data to PagerAdapter that would sent to each fragment
#Override
public void onDialogAddClick(Order order) {
Log.d("test", "onDialogAddClick");
mOrders.add(order);
mDinersPagerAdapter.updateOrders();
}
}
PagerAdapter
package com.slavafleer.tipcalculator02;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import java.util.ArrayList;
/**
* PagerAdapter for ManualModeActivity ViewPager
*/
public class DinersPagerAdapter extends FragmentPagerAdapter {
private int mDinersAmount;
private ArrayList<DinerFragment> mDinerFragments;
public DinersPagerAdapter(FragmentManager fm, int dinersAmount) {
super(fm);
mDinersAmount = dinersAmount;
mDinerFragments = new ArrayList<>();
}
#Override
public Fragment getItem(int position) {
// Insert diners amount to fragment
Bundle bundle = new Bundle();
bundle.putInt(Constants.KEY_DINNERS_AMOUNT, mDinersAmount);
bundle.putInt(Constants.KEY_CURRENT_PAGE, position);
DinerFragment dinerFragment = new DinerFragment();
dinerFragment.setArguments(bundle);
mDinerFragments.add(dinerFragment); // save fragments references
return dinerFragment;
}
// Diners amount + All
#Override
public int getCount() {
return mDinersAmount + 1;
}
// Update order list in each fragment of view pager
public void updateOrders() {
for(DinerFragment dinerFragment : mDinerFragments) {
dinerFragment.onResume();
}
}
}
Fragment
package com.slavafleer.tipcalculator02;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import com.slavafleer.tipcalculator02.recycler.OrdersAdapter;
import java.util.ArrayList;
/**
* Diner Fragment Class
*/
public class DinerFragment extends Fragment implements OrderDialog.Callbacks {
private ArrayList<Order> mOrders = new ArrayList<>();
private RecyclerView mRecyclerViewOrders;
private ImageView mImageViewAddOrderButton;
private int mDinersAmount;
private OrdersAdapter mOrdersAdapter;
private int mDinerId;
private Callbacks mCallbacks;
public DinerFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d("test", "onCreateView");
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_diner, container, false);
mCallbacks = (Callbacks) inflater.getContext();
// Get Diners Amount
final Bundle bundle = getArguments();
if(bundle != null) {
mDinersAmount = bundle.getInt(Constants.KEY_DINNERS_AMOUNT);
mDinerId = bundle.getInt(Constants.KEY_CURRENT_PAGE);
Log.d("test", "onCreateView " + mDinerId);
}
mRecyclerViewOrders = (RecyclerView) view.findViewById(R.id.recyclerViewOrders);
mOrdersAdapter = new OrdersAdapter(getActivity(), mOrders);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
mRecyclerViewOrders.setLayoutManager(linearLayoutManager);
mRecyclerViewOrders.setAdapter(mOrdersAdapter);
// Due to the bug, we could use just listener and not OnClick in Fragment
mImageViewAddOrderButton = (ImageView) view.findViewById(R.id.imageViewAddButton);
mImageViewAddOrderButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
ArrayList<Integer> currentPage = new ArrayList<>();
currentPage.add(mDinerId);
OrderDialog orderDialog = new OrderDialog(getActivity(),
mDinersAmount, currentPage, DinerFragment.this);
orderDialog.show();
}
});
return view;
}
#Override
public void onResume() {
super.onResume();
Log.d("test", "onResume " + mDinerId);
ManualModeActivity activity = (ManualModeActivity) getActivity();
mOrders = activity.getOrders();
for(Order order : mOrders) {
Log.d("test", order.getPrice() + "");
}
int size = mOrders.size();
mOrdersAdapter.notifyDataSetChanged();
mRecyclerViewOrders.smoothScrollToPosition(size);
}
// Blank OrderDialog.Callbacks
// used due to Implements for creation OrderDialog
#Override
public void onDialogAddClick(Order order) {
mCallbacks.onDialogAddClick(order);
}
public interface Callbacks {
void onDialogAddClick(Order order);
}
}

Instead of using onResume use the onPageSelected method and used the passed fragment for context to call the updating method in the fragment.

Finally what I did is replacing mOrdersAdapter.notifyDataSetChanged() on recreating the adapter. I understand that is not a very smart solution but visually it does work as I needed.
I would not mark it as answer cause I still want to know why it acts like I wrote before.
Thanks again.
// mOrdersAdapter.notifyDataSetChanged();
mOrdersAdapter = new OrdersAdapter(getActivity(), mOrders);
mRecyclerViewOrders.setAdapter(mOrdersAdapter);

ViewPager adapter creates 2 fragments at the same time. for instance when you're on page 0, it also creates page 1(lifecycle for page 1: OnCreate->OnCreateView->OnResume->OnPause->OnResume).When you swipe to page 1 only method that is being called is SetMenuVisibility. So in order to update data for page 1 is to call setMenuVisibilty inside of Fragment:
#Override
public void setMenuVisibility(boolean menuVisible) {
super.setMenuVisibility(menuVisible);
if(menuVisible && isResumed()){
settingAdapter();
}
}
So here inside of settingAdapter i reloaded data.
so far,it's the best trick i made toward fragments with recyclerviews inside viewpager. But still there are few milliseconds delay for populating fragment with new data)))
I hope this will help you

Passing Values to ViewPager Fragment

I want to pass dogruYanlis value which is an integer array to these fragments. If I try to handle this with bundle it it sends anything. The array that I received in fragment class is always null. I think that I can't handle with bundle but I don't know how I can solve this problem...
The Activity that I want to send data
package oztiryaki.my;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class result extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private Bundle bundle;
int[] dogruYanlis;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_result);
toolbar = (Toolbar) findViewById(R.id.toolbarResult);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
Bundle list = getIntent().getExtras();
if(list == null){
return;
}
dogruYanlis = list.getIntArray("dogruYanlis");
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
bundle = new Bundle();
bundle.putIntArray("dogruYanlis", dogruYanlis);
result2015Fragment f15 = new result2015Fragment();
f15.setArguments(bundle);
result2014Fragment f14 = new result2014Fragment();
f14.setArguments(bundle);
result2013Fragment f13 = new result2013Fragment();
f13.setArguments(bundle);
adapter.addFragment(f15, "2015");
adapter.addFragment(f14, "2014");
adapter.addFragment(f13, "2013");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
The one of fragment activity
package oztiryaki.my;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
/**
* Created by oztir on 21.02.2016.
*/
public class result2015Fragment extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.result2015,container,false);
int[] dogruYanlis = getArguments().getIntArray("dogruYanlis");
if(dogruYanlis == null){
Toast.makeText(getActivity(),"null sory:(", Toast.LENGTH_LONG).show();
}
TextView ygs1hp = (TextView) v.findViewById(R.id.ygs1hp);
return v;
}
public void getArray(int[] dogruYanlis){
Toast.makeText(getActivity(),Integer.toString(dogruYanlis[0]), Toast.LENGTH_LONG).show();
}
}

I had a similar struggle, maybe this will help. In case if your variables in the activity are not changing after it is created, there is one simple way to reach out to the activity's variables from the fragment it creates:
get the context in the fragment
then you can get the value of the variable from the fragment
Context context;
public void onViewCreated(View v, Bundle savedInstanceState) {
context = getActivity();
int i = ((result)context).dogruYanlis[0];
}

Try to create a Fragment using the wizard that Android studio provides, which gives you a dummy Fragment, with all the Fragment methods you need to pass data and such:
package FRAGMENTS;
import android.app.Fragment;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
public class FragmentLifecycleDemo extends Fragment {
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String TEXT1 = "text1";
private static final String TEXT2 = "text2";
// the two strings are going to be used here
private TextView title;
private TextView subtitle;
private String text1;
private String text2;
private Context c;
private OnFragmentInteractionListener mListener;
public FragmentLifecycleDemo(Context c) {
// Required empty public constructor
this.c = c;
}
public static FragmentLifecycleDemo newInstance(String title, String subtitle, Context c) {
FragmentLifecycleDemo fragment = new FragmentLifecycleDemo(c);
Bundle args = new Bundle();
args.putString(TEXT1, title);
args.putString(TEXT2, subtitle);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Toast.makeText(c, "Hi! onCreate has just been called.", Toast.LENGTH_SHORT).show();
if (getArguments() != null) {
text1 = getArguments().getString(TEXT1);
text2 = getArguments().getString(TEXT2);
}
}
private void init(View v) {
title = (TextView) v.findViewById(R.id.txtTry);
title.setText(text1);
subtitle = (TextView) v.findViewById(R.id.txtReal);
subtitle.setText(text2);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_lifecycle_demo, container, false);
init(v);
Toast.makeText(c, "Greetings from onCreateView!", Toast.LENGTH_SHORT).show();
return v;
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
Toast.makeText(c, "Is it me, or a button has just been pressed?", Toast.LENGTH_SHORT).show();
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
Toast.makeText(c, "Howdy! I've just been attached to the activity.", Toast.LENGTH_SHORT).show();
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
#Override
public void onDetach() {
super.onDetach();
Toast.makeText(c, "Oh no! I've been detached u.u", Toast.LENGTH_SHORT).show();
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
void onFragmentInteraction(Uri uri);
}
}
As you can see, the method where you should get the Bundle is the onCreate one, that receives the data you want to be available on the Fragment, which was send from the constructor named newInstance.

View.onRestoreInstanceState not being called when fragment setRetainInstance(true) (double screen orientation change when fragment is in a back stack)

I have two fragments: one on top of another. Fragments has setRetainInstance(true) in their constructors.
When I do a double screen flip and press back key, top fragment gets popped and bottom fragment becomes visible. But bottom fragment's view do not receive onRestoreInstanceState.
When I remove setRetainInstance(true) everything works just fine. But I need that setRetainInstance(true) to work with multiple threads, so I can't solve my problem that simple. :)
How to guarantee onRestoreInstanceState to be called in this case?
Here is some example code:
package com.example.saverestoreviewstate;
import android.app.Activity;
import android.app.Fragment;
import android.content.Context;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
getFragmentManager().beginTransaction().replace(android.R.id.content, new Fragment1()).commit();
}
}
public static class SaveRestoreView extends TextView {
public SaveRestoreView(Context context) {
super(context);
}
String value;
public void setValue(String value) {
this.value = value;
setText(value);
}
#Override
public Parcelable onSaveInstanceState() {
Bundle bundle = new Bundle();
bundle.putParcelable("super", super.onSaveInstanceState());
bundle.putString("value", value);
return bundle;
}
#Override
public void onRestoreInstanceState(Parcelable state) {
Bundle bundle = (Bundle)state;
super.onRestoreInstanceState(bundle.getParcelable("super"));
value = bundle.getString("value");
setText(value);
}
}
public static class Fragment1 extends Fragment {
private static boolean firstRun = true;
public Fragment1() {
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Context context = inflater.getContext();
LinearLayout layout = new LinearLayout(context);
layout.setId(12);
layout.setOrientation(LinearLayout.VERTICAL);
SaveRestoreView saveRestore = new SaveRestoreView(context);
saveRestore.setId(128);
if (firstRun) {
saveRestore.setValue("*******save this string*******");
firstRun = false;
}
layout.addView(saveRestore);
Button button = new Button(inflater.getContext());
button.setText("Create 2nd fragment");
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
getFragmentManager().beginTransaction().replace(android.R.id.content, new Fragment2()).addToBackStack(null).commit();
}
});
layout.addView(button);
return layout;
}
}
public static class Fragment2 extends Fragment {
public Fragment2() {
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return new View(inflater.getContext());
}
}
}

So, I've finished implementing save/restore logic manually.
The minus is that I can't turn off save\restore that already exist, so onSaveInstance/onRestoreInstance is called twice on a View. Except of that one time when it is not called by itself - then it IS called once B-).
To make it work just add to Fragment1 class:
SparseArray<Parcelable> savedState;
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
if (savedState != null)
view.restoreHierarchyState(savedState);
}
#Override
public void onDestroyView() {
super.onDestroyView();
savedState = new SparseArray<Parcelable>();
getView().saveHierarchyState(savedState);
}