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After changing the screen orientation the fragment is duplicated

I have an activity that creates a fragment programmatically.
the fragment has another fragment inside it.
activity contains fragment A.
fragment A contains fragment B.
everything works perfectly,
except in case I change the orientation of the screen.
when the screen orientation is changed, the fragment is duplicated.
I looked for solutions to my problem on the web (here too),
I covered the official android documentation,
I tried to do my tests:
but I have not come back to find a solution!
I saw other people who have solved by putting the code to create the fragment in this if:
if (savedInstanceState == null) {
}
but it does not work for me!
if I put the code to create the fragment inside that one, no fragment is created.
I tried to segure the life cycle of the activity with the debugging.
when the activity is created for the first time the app passes here:
activity
fragment, onattach
fragment, oncreate
fragment, oncreateview
when I turn the screen horizontally, the app passes here:
fragment, onattach
fragment, oncreate
activity
fragment, oncreateview
fragment, onattach
fragment, oncreate
fragment, oncreateview
activity:
public class Activity extends AppCompatActivity {
ScrollView sv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity);
LinearLayout ll = (LinearLayout) findViewById(R.id.ll);
sv = findViewById(R.id.sv);
LinearLayout ll_fragment = new LinearLayout(this);
ll_fragment.setId(100);
ll_fragment.setOrientation(LinearLayout.VERTICAL);
LinearLayout.LayoutParams LLParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
ll_fragment.setLayoutParams(LLParams);
ll.addView(ll_fragment);
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
ArrayList<Integer> AL_Int = new ArrayList<Integer>();
AL_Int.add(sv.getId());
fragment = FragmentA.newInstance(AL_Int);
fragmentTransaction.add(ll_fragment.getId(), fragment);
fragmentTransaction.commit();
}
fragment:
public class FragmentA extends Fragment {
public static FragmentA newInstance(ArrayList<Integer> AL_Int_sv_ID) {
FragmentA f = new FragmentA();
Bundle b = new Bundle();
if(AL_Int_sv_ID.get(0) != null){
b.putInt("int_sv_ID", AL_Int_sv_ID.get(0));
b.putBoolean("bool_sv", true);
}else{
b.putInt("int_sv_ID", -1);
b.putBoolean("bool_sv", false);
}
f.setArguments(b);
return f;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle args = getArguments();
if (args != null) {
int int_ScrollView_ID = args.getInt("int_sv_ID");
boolean bool_ScrollView = args.getBoolean("bool_sv");
bool_sv = bool_ScrollView;
int_sv_ID = int_ScrollView_ID;
if(bool_sv){
sv = getActivity().findViewById(int_ScrollView_ID);
sv = FA.findViewById(int_ScrollView_ID);
}
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
LinearLayout ll = new LinearLayout(getActivity());
ll.setOrientation(LinearLayout.VERTICAL);
LLParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.MATCH_PARENT);
ll.setLayoutParams(LLParams);
ll.setId(20);
FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
FragmentB fragmentB = new FragmentB();
transaction.add(20, fragmentB);
transaction.commit();
return ll;
}

You need to try again the if (savedInstanceState == null) method. It is the correct way to handle it, you might be doing something wrong, only wrap this 3 lines in the if:
fragment = AutoCompleteTextView_Fragment.newInstance(AL_Int);
fragmentTransaction.add(ll_fragment.getId(), fragment);
fragmentTransaction.commit();

had this same problem, try fragmentTransaction.replace() instead of
fragmentTransaction.add()

Cant understand fragment replace

I have trouble understanding in FragmentTransaction.replace(id, fragment, 'string') what does .replace actually
I read somewhere that it will replace the content of view id with fragment but in my
public class MainActivity extends
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (findViewById(R.id.fragment_container) !=null) {
if(savedInstanceState!=null){
return ;
}
ArticleFragment first_fragment = new ArticleFragment();
HeadlineFragment second_fragment = new HeadlineFragment();
first_fragment.setArguments(getIntent().getExtras());
second_fragment.setArguments(getIntent().getExtras());
FragmentTransaction manager=getSupportFragmentManager().beginTransaction();
manager.add(R.id.fragment_container, first_fragment,"first");
manager.add(R.id.fragment_container, second_fragment,"second");
manager.commit();
}
abc newFragment = new abc();
Bundle args = new Bundle();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, newFragment,"second");
transaction.addToBackStack(null);
transaction.commit();
}
}
it only replaces the first fragment that i added to Transaction, i.e. first_fragment.
And how do i replace a specific fragment?

The issue seems to be with R.id.fragment_container. You should have a different first argument on the line below in order to replace a fragment that is not your "first" fragment:
manager.add(R.id.fragment_container, second_fragment,"second");

Add and remove fragment null pointer

I have two fragments that are in the main activity and i want to refresh them when something occurs.
Now the code works for second fragment, but won't work for the first, and i am not sure why.
I have been looking at the code for about an hour, and i can't seem to find a reason.
Here is the code
public class MainActivity extends FragmentActivity {
Fragment frag,frag2;
FragmentManager fm;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String screen = getString(R.string.screen_type);
/*
* Get a reference to fragment manager
* Wire the container to represent fragment
*/
fm = getSupportFragmentManager();
frag = fm.findFragmentById(R.id.container);
if(screen.equals("large")){
frag2 = fm.findFragmentById(R.id.containerDetails);
loadFragments(frag,frag2,fm);
}
/*Loads the fragment into the activity*/
else
loadFragment(frag,fm);
}
private void loadFragments(Fragment frag, Fragment frag2, FragmentManager fm) {
if(frag == null && frag2 == null){
frag = new DisplayFragment();
frag2 = new DetailsFragment();
fm.beginTransaction().add(R.id.container,frag).add(R.id.containerDetails, frag2).commit();
}
}
private void loadFragment(Fragment frag, FragmentManager fm) {
if(frag == null){
frag = new DisplayFragment();
fm.beginTransaction().add(R.id.container,frag).commit();
}
}
public void updateDetails(int position) {
// Reload current fragment
if(frag2!=null)fm.beginTransaction().remove(frag2).commit();
frag2 = new DetailsFragment();
Bundle b = new Bundle();
b.putInt("Id",position);
frag2.setArguments(b);
fm.beginTransaction().add(R.id.containerDetails, frag2).commit();
}
public void updateDisplay() {
// Reload current fragment
if(frag!=null)fm.beginTransaction().remove(frag).commit(); //THIS IS ALWAYS NULL FOR SOME REASON
frag = new DisplayFragment();
fm.beginTransaction().add(R.id.container, frag).commit();
}
public void refreshDetails() {
// Reload current fragment
if(frag2!=null)fm.beginTransaction().remove(frag2).commit();
frag2 = new DetailsFragment();
fm.beginTransaction().add(R.id.containerDetails, frag2).commit();
}
}
The first fragment is always null, and it doesn't get removed, instead another fragment is pasted over that, and creates a mess.

Try using replace() method rather than add()

Android - Dynamic Fragment problems on orientation change

I'm having a problem with dynamic fragment . If I'm not change orientation , it work fine . When I change orientation , I click on ListView item . It's not change textview .
This is DynamicActivity class
public class DynamicActivity extends Activity implements FragmentCoordinator{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dynamic);
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
ListContentFragment listContentFragment = new ListContentFragment();
DetailsContentFragment detailsContentFragment = new DetailsContentFragment();
transaction.add(R.id.listContainer, listContentFragment,"listContent");
transaction.add(R.id.detailsContainer, detailsContentFragment,"detailsContent");
transaction.commit();
}
#Override
public void onSetContentDetails(int index) {
FragmentManager fragmentManager = getFragmentManager();
DetailsContentFragment detailsContentFragment = (DetailsContentFragment)fragmentManager.findFragmentByTag("detailsContent");
detailsContentFragment.setContentDetails(index);
}
}
And DetailsContentFragment class
public class DetailsContentFragment extends Fragment {
TextView lbMess;
String[] array;
int saveIndex;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.details_content_fragment, container,false);
array = getResources().getStringArray(R.array.list_details);
lbMess = (TextView)v.findViewById(R.id.lbDetails);
int currentIndex = savedInstanceState == null ? 0 : savedInstanceState.getInt("indexContent",0);
setContentDetails(currentIndex);
return v;
}
#Override
public void onSaveInstanceState(Bundle outState) {
outState.putInt("indexContent", saveIndex);
}
public void setContentDetails(int index) {
saveIndex = index;
lbMess.setText(array[saveIndex]);
}
}
I have debug but it doesn't have any error . Please give me some advice

I found the problems are :
When the system destroys and re-creates an activity because of a run-time configuration change, the activity automatically
re-instantiates existing fragments.
This isn’t a problem for “static” fragments declared in the activity’s layout.
But for “dynamic” fragments, i need to test for this situation to prevent creating a second instance of my fragment.
I check the Bundle argument passed to my activity’s onCreate() is null.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dynamic);
if(savedInstanceState == null)
{
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
ListContentFragment listContentFragment = new ListContentFragment();
DetailsContentFragment detailsContentFragment = new DetailsContentFragment();
transaction.add(R.id.listContainer, listContentFragment,"listContent");
transaction.add(R.id.detailsContainer, detailsContentFragment,"detailsContent");
transaction.commit();
}
}
And it work fine . I think is helpful for someone have same problems .

Android replace the current fragment with another fragment

I just started with fragment design for HoneyComb. I created two fragments. When i click a button in the left side fragment, a new fragment is created in right side. Meanwhile when i click a button in the right fragment(ie. DetialsFragment in my code below should be replaced by another fragment.
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<fragment class="com.fragment.example.Titles"
android:id="#+id/titles" android:layout_weight="1"
android:layout_width="0px"
android:layout_height="match_parent" />
<FrameLayout android:id="#+id/details" android:layout_weight="1"
android:layout_width="0px"
android:layout_height="match_parent" />
</LinearLayout>
FragmentExample.java
public class FragmentExample extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
Titles.java
public class Titles extends Fragment {
public FragmentTransaction ft;
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.main1, null);
Button button1 = (Button)v.findViewById(R.id.button1);
button1.setText("santhosh");
button1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
DetailsFragment details = (DetailsFragment)
getFragmentManager().findFragmentById(R.id.details);
if (details == null || details.getShownIndex() != 1) {
// Make new fragment to show this selection.
details = DetailsFragment.newInstance(1);
// Execute a transaction, replacing any existing
// fragment with this one inside the frame.
ft
= getFragmentManager().beginTransaction();
ft.add(R.id.details, details, "detail");
ft.setTransition(
FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
}
}
});
return v;
}
}
DetailsFragment.java
public class DetailsFragment extends Fragment {
/**
* Create a new instance of DetailsFragment, initialized to
* show the text at 'index'.
*/
Titles title = new Titles();
String[] titles = {"Title1", "Title2", "Title3", "Title4"};
public static DetailsFragment newInstance(int index) {
DetailsFragment f = new DetailsFragment();
// Supply index input as an argument.
Bundle args = new Bundle();
args.putInt("index", index);
f.setArguments(args);
return f;
}
public int getShownIndex() {
return getArguments().getInt("index", 0);
}
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
if (container == null) {
// Currently in a layout without a container, so no
// reason to create our view.
return null;
}
Button button = new Button(getActivity());
button.setText("Next");
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
});
return button;
}
}

Then provided your button is showing and the click event is being fired you can call the following in your click event:
final FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.details, new NewFragmentToReplace(), "NewFragmentTag");
ft.commit();
and if you want to go back to the DetailsFragment on clicking back ensure you add the above transaction to the back stack, i.e.
ft.addToBackStack(null);
Or am I missing something? Alternatively some people suggest that your activity gets the click event for the button and it has responsibility for replacing the fragments in your details pane.

Latest Stuff
Okay. So this is a very old question and has great answers from that time. But a lot has changed since then.
Now, in 2020, if you are working with Kotlin and want to change the fragment then you can do the following.
Add Kotlin extension for Fragments to your project.
In your app level build.gradle file add the following,
dependencies {
def fragment_version = "1.2.5"
// Kotlin
implementation "androidx.fragment:fragment-ktx:$fragment_version"
// Testing Fragments in Isolation
debugImplementation "androidx.fragment:fragment-testing:$fragment_version"
}
Then simple code to replace the fragment,
In your activity
supportFragmentManager.commit {
replace(R.id.frame_layout, YourFragment.newInstance(), "Your_TAG")
addToBackStack(null)
}
References
Check latest version of Fragment extension
More on Fragments

You can try below code. it’s very easy method for push new fragment from old fragment.
private int mContainerId;
private FragmentTransaction fragmentTransaction;
private FragmentManager fragmentManager;
private final static String TAG = "DashBoardActivity";
public void replaceFragment(Fragment fragment, String TAG) {
try {
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(mContainerId, fragment, tag);
fragmentTransaction.addToBackStack(tag);
fragmentTransaction.commitAllowingStateLoss();
} catch (Exception e) {
// TODO: handle exception
}
}

Use android.support.v4.app for FragmentManager & FragmentTransaction in your code, it has worked for me.
DetailsFragment detailsFragment = new DetailsFragment();
android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.details,detailsFragment);
fragmentTransaction.commit();

If you have a handle to an existing fragment you can just replace it with the fragment's ID.
Example in Kotlin:
fun aTestFuction() {
val existingFragment = MyExistingFragment() //Get it from somewhere, this is a dirty example
val newFragment = MyNewFragment()
replaceFragment(existingFragment, newFragment, "myTag")
}
fun replaceFragment(existing: Fragment, new: Fragment, tag: String? = null) {
supportFragmentManager.beginTransaction().replace(existing.id, new, tag).commit()
}

Updated Answer (Working for Overlap problem as well)
#aniket-thakur(https://stackoverflow.com/users/2396539/aniket-thakur) gave correct answer. Thank you for that!
But, getFragmentManager() is deprecated, so following code did work for me.
final FragmentTransaction ft = getParentFragmentManager().beginTransaction();
ft.replace(R.id.nav_host_fragment, new GalleryFragment(), "NewFragmentTag");
ft.addToBackStack(null);
ft.commit();

it's very simple how to replace with Fragment.
DataFromDb changeActivity = new DataFromDb();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.changeFrg, changeActivity);
transaction.commit();