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How to get value from childfragment to parentfragment?

I am frustrated.
i want to get value from child fragment to parent fragment
i had tries many method.
interface, viewModel, sharedpreferences but no one work.
I had follow this method
but it doesn't work for me.
here my code parent fragment:
public class Chart_Fragment extends Fragment
implements Product_Fragment.pf_interface {
String dt;
TextView tv;
public Chart_Fragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.chart_fragment, container, false);
// create product_fragment as childfragment
FragmentManager fm = getChildFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
Product_Fragment product_fragment = new Product_Fragment();
ft.replace(R.id.fl_two, new Product_Fragment());
ft.commit();
return v;
}
public void onViewCreated(View v, Bundle savedInstanceState){
super.onViewCreated(v,savedInstanceState);
tv = (TextView)v.findViewById(R.id.rcv);
}
#Override
public void data(String d) {
FragmentManager fragmentManager = getChildFragmentManager();
Product_Fragment product_fragment =
(Product_Fragment)fragmentManager.findFragmentByTag("data");
if(product_fragment != null){
String dt = d;
tv.setText(dt);
}
}
}
and my childfragment is :
public class Product_Fragment extends Fragment {
private pf_interface pf;
public Product_Fragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.product_fragment, container, false);
Button b = (Button)v.findViewById(R.id.btn_sender);
b.setOnClickListener(new btnClick());
return v;
}
public void onAttachToParentFragment(Fragment fragment){
try {
pf = (pf_interface)fragment;
}catch (ClassCastException e){
throw new ClassCastException(
fragment.toString()+ "must implement pf_interface"
);
}
}
public void onCreate(Bundle savedInstanceState){
Log.i(TAG, "onCreate");
super.onCreate(savedInstanceState);
onAttachToParentFragment(getParentFragment());
}
private class btnClick implements View.OnClickListener{
#Override
public void onClick(View v) {
switch (v.getId()){
case R.id.btn_sender:
if(pf != null){
pf.data("button click interface");
}break;
}
}
}
public interface pf_interface{
void data(String d);
}
}
textview on parent fragment didn't show the string d ("button click interface")from child fragment

Why you're checking for child fragment in callback on your parent fragment ?
#Override
public void data(String d) {
FragmentManager fragmentManager = getChildFragmentManager();
Product_Fragment product_fragment =
(Product_Fragment)fragmentManager.findFragmentByTag("data");
if(product_fragment != null){ // Why to check for child fragment nullability?
String dt = d;
tv.setText(dt);
}
}
You can directly use like this:
#Override
public void data(String d) {
tv.setText(d);
}
Note: on any certain scenario if any of object is null, your callback won't be executed. You've already check for null reference.

fragment getView() method is NULL in FragmentTransaction

I have two fragment inside a LinearLayout.
When I click on a FAB button I would like to hide one but a
null object reference appears on FragmentTransaction hide method.
Why doesn't "f" have a view reference?
public class FragmentOne extends Fragment {
public FragmentOne() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View returnView = inflater.inflate(R.layout.fragment_one, container, false);
FloatingActionButton fabTemp = returnView.findViewById(R.id.fabTemp);
final Fragment f = getActivity().getSupportFragmentManager().getFragments().get(0).getChildFragmentManager().getFragments().get(1);
final FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
fabTemp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
transaction.setCustomAnimations(android.R.animator.fade_in,
android.R.animator.fade_out);
if (f.isHidden()) {
transaction.show(f);
} else {
transaction.hide(f);
}
transaction.commit();
}
});
return returnView;
}
I solved in another way despite not being as i wanted
final View frag = getView().findViewById(R.id.frgSettemp);
frag.setVisibility(View.GONE);

In onCreateView just inflate and return the view.
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View returnView = inflater.inflate(R.layout.fragment_one, container, false);
return returnView;
}
Try the other processing in onViewCreated #override method. like this
#Override
public void onViewCreated(View v, Bundle savedInstanceState) {
super.onViewCreated(v, savedInstanceState);
FloatingActionButton fabTemp = getView().findViewById(R.id.fabTemp);
final Fragment f = getActivity().getSupportFragmentManager().getFragments().get(0);
final FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
fabTemp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
transaction.setCustomAnimations(android.R.animator.fade_in,
android.R.animator.fade_out);
if (f.isHidden()) {
transaction.show(f);
} else {
transaction.hide(f);
}
transaction.commit();
}
});
}
Hope this will help.

You should call only
final Fragment f = getActivity().getSupportFragmentManager().getFragments().get(0);
or
final Fragment f = getActivity().getSupportFragmentManager().getFragments().get(1);
What you have done will return null for sure.

After two different fragments have been replaced, first fragment is recreated when on pressed back button

I have three fragment and one activity. It works this way:
[activity]-> [MainFragment]->[MenuFragment]->[SignUpFragment]
When [SignUpFragment] is back pressed, the [MainFragment] is created twice.
I tried setRetaInInstance(true) and I checked savedInstanceState but I can not prevent [MainFragment] recreating.
This is my MainActivity:
public class MainActivity extends AppCompatActivity {
public Bundle mSavedInstanceState;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mSavedInstanceState = savedInstanceState;
setContentView(R.layout.activity_main);
}
#Override
protected void onResume() {
super.onResume();
callMainFragment();
}
private void callMainFragment() {
if (mSavedInstanceState == null) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.container_category, new MainFragment(), MainFragment.class.getSimpleName());
transaction.addToBackStack(null);
transaction.commit();
}
}
public ActionBar getMainActionBar(){
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
// Action Bar Display settings
actionBar.setDisplayShowCustomEnabled(true);
actionBar.setDisplayShowTitleEnabled(false);
// Custom view inflater
LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// Custom layout view
View viewActionBar = inflater.inflate(R.layout.action_bar, null);
// Set custom view
actionBar.setCustomView(viewActionBar);
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
}
return actionBar;
}
This is my MainFragment:
public class MainFragment extends BaseFragment implements AdapterView.OnItemClickListener, BuyersGuideCategoriesDelegate, View.OnClickListener {
private Bundle mSavedInstanceState;
private BuyersGuideCategoriesFragment mCategoriesFragment;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setRetainInstance(true);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
mSavedInstanceState = savedInstanceState;
if (mSavedInstanceState == null) {
mView = inflater.inflate(R.layout.fragment_main, container, false);
// Call Grid View Buyers Guide Fragment
mCategoriesFragment = new BuyersGuideCategoriesFragment();
mCategoriesFragment.mGridViewDelegate = this;
setIcons();
setTitles();
setTexts();
initListView();
}
return mView;
}
#Override
public void onResume() {
super.onResume();
ImageView menu = (ImageView) ((MainActivity) getActivity()).getMainActionBar().getCustomView().findViewById(R.id.action_bar_menu_icon);
menu.setOnClickListener(this);
}
#Override
public void onClick(View v) {
if (mSavedInstanceState == null) {
MainActivity activity = (MainActivity) getActivity();
FragmentManager manager = activity.getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.container_category, new MenuFragment(),MenuFragment.class.getSimpleName());
transaction.addToBackStack(null);
transaction.commit();
}
}
}
This is my MenuFragment:
public class MenuFragment extends BaseFragment implements AdapterView.OnItemClickListener, View.OnClickListener {
private Bundle mSavedInstanceState;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
mSavedInstanceState = savedInstanceState;
if (savedInstanceState == null) {
mView = inflater.inflate(R.layout.fragment_menu, container, false);
setMenuItemsListViewAdapter();
}
return mView;
}
private void setMenuItemsListViewAdapter() {
ListView menuItems = (ListView) mView.findViewById(R.id.list_menu_items);
ListMenuItemsListViewAdapter adapter = new ListMenuItemsListViewAdapter(getContext(),getMenuItemNames());
menuItems.setAdapter(adapter);
menuItems.setOnItemClickListener(this);
}
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
switch ((String) parent.getAdapter().getItem(position)){
case SIGN_UP:
replaceFragment(R.id.container_category,new SignUpFragment(),SignUpFragment.class.getSimpleName());
break;
}
}
private void replaceFragment(int containerId,Fragment fragment, String fragmentTag){
if (mSavedInstanceState == null){
MainActivity activity = (MainActivity) getActivity();
FragmentManager manager = activity.getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(containerId,fragment,fragmentTag);
transaction.addToBackStack(null);
transaction.commit();
}
}
#Override
public void onClick(View v) {
switch (v.getId()){
case R.id.menu_back_icon:
replaceFragment(R.id.container_category, new MainFragment(),MainFragment.class.getSimpleName());
break;
}
}
}
And this is my SignUpFragment:
public class SignUpFragment extends BaseFragment implements View.OnClickListener{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (savedInstanceState == null) {
mView = inflater.inflate(R.layout.fragment_sign_up, container, false);
}
return mView;
}
}
EDIT 1: The MainFragment is recreated only when I return from SignUpFragment to MenuFragment. I am doing wrong using so many fragments? Should I use activity?

When you are move between Fragments, call addToBackStack() :
FragmentTransaction ft = fragmentManager.beginTransation();
ft.replace( R.id.fragment, new MyFragment() ).addToBackStack( "ftransaction" ).commit();

Create first Fragment:
FragmentTransaction ft = fragmentManager.beginTransation();
ft.add(R.id.container, new FirstFragment()).addToBackStack(null).commit();
Second:
FragmentTransaction ft = fragmentManager.beginTransation();
ft.replace(R.id.container, new SecondFragment()).addToBackStack(null).commit();
and Third:
FragmentTransaction ft = fragmentManager.beginTransation();
ft.replace(R.id.container, new ThirdFragment()).commit();

Fragment still visible after popBackStack

In my MainActivity there is a FrameLayout (id=fragment_container) that is replaced by the Activity in onCreate with FragmentA. FragmentA just contains a single Button and calls onClick in the MainActivity in order to replace the FrameLayout with FragmentB. FragmentB contains a RecyclerView and is shown correctly. I call fragmentManager.popBackStack() to bring back FragmentA. Now FragmentA is shown on top of FragmentB (which I still can interact with).
Why is FragmentB not removed after calling popBackStack?
MainActivity
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private FragmentManager fragmentManager;
#Override
public void onBackPressed() {
fragmentManager.popBackStack();
}
#Override
public void onClick(View view) {
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, new FragmentB());
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//...
fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
FragmentA fragment = FragmentA.getInstance(this); //register OnClickListener
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();
}
//...
}
FragmentA
public class FragmentA extends Fragment {
private View.OnClickListener onClickListener;
public FragmentA() {
}
#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_a, container, false);
FloatingActionButton fab = (FloatingActionButton) view.findViewById(R.id.fab);
fab.setOnClickListener(onClickListener);
return view;
}
public static FragmentA getInstance(View.OnClickListener onClickListener) {
FragmentA fragmentA = new FragmentA();
fragmentA.setOnClickListener(onClickListener);
return fragmentA;
}
private void setOnClickListener(View.OnClickListener onClickListener) {
this.onClickListener = onClickListener;
}
}
FragmentB
public class FragmentB extends Fragment {
//...
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.FragmentB, container, true);
//manipulating Views...
//...
return view;
}
}

The problem is in the FragmentB class. You should not pass the argument attachToRoot=true.
Try this instead:
public class FragmentB extends Fragment {
//...
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
//don't pass true
View view = inflater.inflate(R.layout.FragmentB, container, false);
//manipulating Views...
//...
return view;
}
}

Use popBackStackImmediate instead,
#Override
public void onBackPressed() {
fragmentManager.popBackStackImmediate();
}
From the popBackStackImmediate docs,
Like popBackStack(), but performs the operation immediately inside of the call. This is like calling executePendingTransactions() afterwards.

How to come back on the start fragment from the 2_nd,3_rd fragments?

Here is my code
I need to go from A->B->C and onBackPressed() from B and C should go to A
while pressing back it goes to B and then to C , It seems to me that transaction.addToBackStack(null); not using as needed
public class TestfragmentActivity extends FragmentActivity{
private FrameLayout layout;
private String TAG = "TAG";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_fragment);
layout = (FrameLayout) findViewById(R.id.container);
A fragment = new A();
doFragmentTransaction(fragment, false);
}
private void doFragmentTransaction(Fragment fragment, boolean addToBackstack) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.add(R.id.container, fragment);
if (addToBackstack)
transaction.addToBackStack(TAG);
transaction.commit();
}
///////////////
public class A extends Fragment {
private Button button;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.test_fragment1, null);
button = (Button) view.findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
B fragment = new B();
doFragmentTransaction(fragment, true);
}
});
return view;
}
private void doFragmentTransaction(Fragment fragment, boolean addToBackstack) {
FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.container, fragment);
if (addToBackstack) {
transaction.addToBackStack(null);
}
transaction.commit();
}
//////////////////////
public class B extends Fragment {
private Button button;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.test_fragment2, null);
button = (Button) view.findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
C fragment = new C();
doFragmentTransaction(fragment, false);
}
});
return view;
}
private void doFragmentTransaction(Fragment fragment, boolean addToBackstack) {
FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.container, fragment);
if (addToBackstack)
transaction.addToBackStack(null);
transaction.commit();
}
}
}

in fragment B and C,
#Override
public void onBackPressed() {
}
in the function, replace the Container with Fragment A.