The Android fragment lifecycle shows that when a fragment is added to the backstack and then removed/replaced, onDestroyView() is called, and later on, when the fragment returns to the layout from the backstack, onCreateView() is called.
From my understanding it means that the fragment's view is being destroyed and recreated. If the user has input text in an EditText in fragment A and goes to fragment B and then back to A, when the fragment comes back the EditText's contents will have been erased.
However, this is not happening in the following code; can anybody explain why? I have already verified that FragmentA's onDestroyView() is being called.
MainActivity.java
public class MainActivity extends FragmentActivity {
private Fragment currentFragment = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
addFragment(new FragmentA());
}
}
public void setCurrentFragment(Fragment fragment) {
this.currentFragment = fragment;
}
#Override
public void onBackPressed() {
if (currentFragment instanceof FragmentB) {
getSupportFragmentManager().popBackStackImmediate();
} else {
super.onBackPressed();
}
}
public void addFragment(Fragment fragment) {
getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment).addToBackStack(null).commit();
setCurrentFragment(fragment);
}
}
FragmentA.java
public class FragmentA extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_a, container, false);
final EditText editText = (EditText)view.findViewById(R.id.editText);
Button button = (Button)view.findViewById(R.id.button);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
FragmentB fragmentB = new FragmentB();
Bundle arguments = new Bundle();
arguments.putString("text", editText.getText().toString());
fragmentB.setArguments(arguments);
((MainActivity)getActivity()).addFragment(fragmentB);
}
});
return view;
}
#Override
public void onDestroyView() {
super.onDestroyView();
Log.d("Tag", "FragmentA.onDestroyView() has been called.");
}
}
FragmentB.java
public class FragmentB extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_b, container, false);
TextView textView = (TextView)view.findViewById(R.id.textView);
textView.setText(getArguments().getString("text"));
return view;
}
}
activity_main.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.fragmenttest.MainActivity"
tools:ignore="MergeRootFrame" />
fragment_a.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<EditText
android:id="#+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" />
</LinearLayout>
fragment_b.xml
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/textView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
Fragments in back stack retain their state in a Bundle. This includes the view hierarchy state with the current contents of EditTexts and such.
To destroy The Fragment .. Use This onDestroyView
or in onDetach
if (fragment != null) {
fragment = new YourFragment();
FragmentTransaction ft = getActivity().getFragmentManager().beginTransaction();
ft.remove(fragment);
ft.commit();
}
Related
The main screen of the app is for bottom navigation.
And there are 3 menus, all of which are fragments.
Pressing the button on one of the fragments opens the dialog fragment window.
And when the dialog is closed, the old fragment should be switched to another new fragment.
I use show() and hide() instead of replace().
MainAcitivity.java
public class MainActivity extends AppCompatActivity {
BottomNavigationView bottomNav;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bottomNav = findViewById(R.id.bottom_nav);
bottomNav.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction transaction = fm.beginTransaction();
Fragment curFrag = fm.getPrimaryNavigationFragment();
String tag = String.valueOf(item.getItemId());
int id = item.getItemId();
if(curFrag != null) {
transaction.hide(curFrag);
}
Fragment fragment = fm.findFragmentByTag(tag);
if(fragment == null) {
if(id == R.id.list)
fragment = new WorkoutListFragment();
transaction.add(R.id.content_layout, fragment);
}
else {
transaction.show(fragment);
}
transaction.setPrimaryNavigationFragment(fragment);
transaction.setReorderingAllowed(true);
transaction.commitNow();
return true;
}
});
}
// Switch to another fragment when the dialog is closed
public void onFragmentChanged() {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
String tag = "ABC";
Fragment currentFragment = fragmentManager.getPrimaryNavigationFragment();
if (currentFragment != null) {
fragmentTransaction.hide(currentFragment);
}
Fragment fragment = fragmentManager.findFragmentByTag(tag);
if (fragment == null) {
fragment = new WriteRoutineFragment();
fragmentTransaction.add(R.id.container, fragment, tag);
} else {
fragmentTransaction.show(fragment);
}
fragmentTransaction.setPrimaryNavigationFragment(fragment);
fragmentTransaction.setReorderingAllowed(true);
fragmentTransaction.commitNow();
}
}
DialogFragment.java
Button startBtn;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_body_part_dialog, null);
startBtn = view.findViewById(R.id.check);
startBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
MainActivity activity = (MainActivity) getActivity();
activity.onFragmentChanged(); // change fragment
dismiss();
}
});
return view;
}
#NonNull
#Override
public Dialog onCreateDialog(#Nullable Bundle savedInstanceState) {
Dialog dialog = super.onCreateDialog(savedInstanceState);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
dialog.setCanceledOnTouchOutside(false);
return dialog;
}
}
WriteRoutineFragment.java
public class WriteRoutineFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_write_routine, container, false);
return rootView;
}
}
ERROR
java.lang.IllegalArgumentException: No view found for id 0x7f0a0082 (com.example.writeweight:id/container) for fragment WriteRoutineFragment{f3a9b6 (137e8e27-12af-4e5a-9397-2cbdc80ed980) id=0x7f0a0082 ABC}
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:875)
at androidx.fragment.app.FragmentManagerImpl.addAddedFragments(FragmentManagerImpl.java:2100)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1874)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1830)
at androidx.fragment.app.FragmentManagerImpl.execSingleAction(FragmentManagerImpl.java:1696)
at androidx.fragment.app.BackStackRecord.commitNow(BackStackRecord.java:293)
at com.example.writeweight.activity.MainActivity.onFragmentChanged(MainActivity.java:78)
at com.example.writeweight.fragment.BodyPartDialogFragment$2.onClick(BodyPartDialogFragment.java:89)
at android.view.View.performClick(View.java:8160)
at android.widget.TextView.performClick(TextView.java:16221)
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992)
at android.view.View.performClickInternal(View.java:8137)
at android.view.View.access$3700(View.java:888)
at android.view.View$PerformClick.run(View.java:30236)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:246)
at android.app.ActivityThread.main(ActivityThread.java:8506)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
I/Process: Sending signal. PID: 23516 SIG: 9
ADDED
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".activity.MainActivity">
<FrameLayout
android:id="#+id/content_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toTopOf="#id/bottom_nav"/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/bottom_nav"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="#menu/bottom_nav_menu"/>
</androidx.constraintlayout.widget.ConstraintLayout>
fragment_write_routine.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".fragment.WriteRoutineFragment">
<!-- TODO: Update blank fragment layout -->
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/hello_blank_fragment" />
</FrameLayout>
When you say
fragmentTransaction.add(R.id.container, fragment, tag);
What you're saying is that you want the FragmentManager to find the R.id.container in your layout and add your fragment to that container. As you're using getSupportFragmentManager(), you're using the Activity's FragmentManager and hence, R.id.container needs to be in your activity's layout. However, R.id.container isn't in your activity's layout, which is why you're getting an exception.
Instead, you should be using the container that is in your Activity's layout - R.id.content_layout:
fragmentTransaction.add(R.id.content_layout, fragment, tag);
Theoretically, lets say i have two classes with corresponding XML files - Activity and Frag
Activity.java
public class Activity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Fragment fragment = new Frag();
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.fragmentArea, fragment);
ft.commit();
}
}
Frag.java
public class Frag extends Fragment {
private TextView txtView;
public Frag() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_, container, false);
txtView = view.findViewById(R.id.textView);
return view;
}
public void setTextView(String str) {
txtView.setText(str);
}
}
activity xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.eksamen.chris.eksempelfragment.Activity">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:id="#+id/fragmentArea">
</LinearLayout>
</android.support.constraint.ConstraintLayout>
Fragment xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.eksamen.chris.eksempelfragment.Frag">
<!-- TODO: Update blank fragment layout -->
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Fragment"
android:id="#+id/textView"/>
</FrameLayout>
As you can see, i have the method setTextView() in my Frag class. Obviously enough, what i would like to do is to call that method from my Activity class.
I have tried grasping this for some hours now, and i really cannot figure out a way to do this. Every example/tutorial out there makes my app crash.
Could someone explain to me how this works, taken the example we have in hand into consideration? Or maybe there is a better way to provide the fragment with data from my activity?
I'd be grateful!
Edit: awful indentation, had some issues, trying to fix.
In order to pass data from Activity to Fragment , you have to use :
Bundle
which is a KEY VALUE data structure for passing values between fragments and activity so at your onCreate() in Activity class will be
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String str = "your_string_here";
// 1 -
Bundle bundle = new Bundle();
// 2 -
bundle.putString("KEY", str);
Fragment fragment = new Frag();
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
// 3 -
fragment.setArguments(bundle);
ft.replace(R.id.fragmentArea, fragment);
ft.commit(); }
and at your fragment
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_, container, false);
txtView = view.findViewById(R.id.textView);
// 4 - NOTE : Should hould the same key at the Activity class :
String str = getArguments().getString("KEY");
setTextView(str);
return view;
}
I am sending data from one fragment to another, using interface. This works absolutely fine. Now I am trying to use onSaveInstanceState() to save the value in
a Fragment and retrieving in onCreate(). however i'm getting null in Bundle of onCreate(). P.S. everything works fine when i set the Fragment directly into the activity layout in xml. but when i set the fragment through java code into the activity, the onSaveInstanceState is failing. It is not saving the last known value. Please help. Pasting the code below. You can try it out to know the exact issue.
Fragment_A :
public class Fragment_A extends Fragment implements View.OnClickListener {
Button btnAdd;
int counter = 0;
Communicator comm;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(savedInstanceState != null){
counter = savedInstanceState.getInt("counter", 0);
}
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_a, container, false);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
comm = (Communicator) getActivity();
btnAdd = (Button) getActivity().findViewById(R.id.btnAdd);
btnAdd.setOnClickListener(this);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("counter", counter);
}
#Override
public void onClick(View v) {
counter++;
comm.sendData(counter);
}
}
interface Communicator{
void sendData(int i);
}
=====
Activity :
public class Activity_InterComm extends Activity implements Communicator{
FragmentManager manager;
FragmentTransaction transaction;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_intercomm);
Fragment_A fragment_1 = new Fragment_A();
Fragment_B fragment_2 = new Fragment_B();
manager = getFragmentManager();
transaction = manager.beginTransaction();
transaction.add(R.id.frag_a, fragment_1, "Frag1");
transaction.add(R.id.frag_b, fragment_2, "Frag2");
transaction.commit();
}
#Override
public void sendData(int i) {
manager = getFragmentManager();
Fragment_B fragment_b = (Fragment_B) manager.findFragmentById(R.id.frag_b);
fragment_b.setData("Button has been clicked " + i + " times");
}
}
=====
Fragment_B :
public class Fragment_B extends Fragment {
TextView txtMessage;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_b, container, false);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
txtMessage = (TextView) getActivity().findViewById(R.id.txtMessage);
}
public void setData(String message){
txtMessage.setText(message);
}
}
activity_intercomm.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="vertical">
<!--<fragment
android:id="#+id/frag_a"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:name="android.learning.com.fragintercomm.Fragment_A"/>
<fragment
android:id="#+id/frag_b"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:name="android.learning.com.fragintercomm.Fragment_B"/>-->
<LinearLayout
android:id="#+id/frag_a"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:background="#color/colorAccent"
android:orientation="vertical"/>
<LinearLayout
android:id="#+id/frag_b"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:background="#color/colorPrimaryDark"
android:orientation="vertical"/>
</LinearLayout>
the soluion I found was using getView() instead of getActivity() while initializing the button in Fragment_A. use btnAdd = (Button) getView().findViewById(R.id.btnAdd); instead of btnAdd = (Button) getActivity().findViewById(R.id.btnAdd);.
However, you can't use getView() in Fragment_B. The Textview freezes and, onSaveInstanceStat() doesn't work. Please suggest a solution.
The following is layout
test.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button android:layout_width="wrap_content" android:layout_height="wrap_content"
android:text="Click"
android:id="#+id/button"
/>
<!-- Framelayout to display Fragments -->
<FrameLayout
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
test_detail.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Hello"
android:id="#+id/textView" android:layout_gravity="center_horizontal"/>
</LinearLayout>
common_view_pager_layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="#+id/MainViewerPage"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<android.support.v4.view.PagerTabStrip
android:id="#+id/TitlePageTabStrip"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.v4.view.ViewPager>
</LinearLayout>
The following is my Activity code
public class TestFragmentActivity extends FragmentActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.test);
Button button = (Button) this.findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, new HomeFragment()).commit();
}
});
}
public class HomeFragment extends Fragment {
private PagerAdapter _adapter;
public HomeFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.common_view_pager_layout, container, false);
this._adapter = new PagerAdapter(TestFragmentActivity.this);
this._adapter.add(new DetailFragment());
ViewPager pager = (ViewPager) view.findViewById(R.id.MainViewerPage);
pager.setAdapter(this._adapter);
return view;
}
}
public class DetailFragment extends Fragment {
public DetailFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.test_detail, container, false);
return rootView;
}
}
public class PagerAdapter extends FragmentPagerAdapter {
private ArrayList<Fragment> _fragments;
public PagerAdapter(FragmentActivity activity) {
super(activity.getSupportFragmentManager());
this._fragments = new ArrayList<Fragment>();
}
public void add(Fragment fragment) {
this._fragments.add(fragment);
}
#Override
public Fragment getItem(int position) {
return this._fragments.get(position);
}
#Override
public CharSequence getPageTitle(int position) {
return "Test";
}
#Override
public int getCount() {
return 1;
}
}
}
When I click a button the fragment in ViewPager was display
But when I click the button again the fragment disappear
Please help me.
try using this:
in the constructor of your adapter change this :
public class MyPagerAdapter extends FragmentPagerAdapter {
private ArrayList<Fragment> _fragments;
public MyPagerAdapter(FragmentManager activity) {
super(activity);
this._fragments = new ArrayList<Fragment>();
}
public void add(Fragment fragment) {
this._fragments.add(fragment);
}
#Override
public Fragment getItem(int position) {
return this._fragments.get(position);
}
#Override
public CharSequence getPageTitle(int position) {
return "Test";
}
#Override
public int getCount() {
return 1;
}
}
and when you want to create the adapter send getChildFragmentManager() to its constructor
public class HomeFragment extends Fragment {
private MyPagerAdapter _adapter;
public HomeFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.common_view_pager_layout, container, false);
ViewPager pager = (ViewPager) view.findViewById(R.id.MainViewerPage);
this._adapter = new MyPagerAdapter(getChildFragmentManager());
this._adapter.add(new DetailFragment());
pager.setAdapter(this._adapter);
return view;
}
}
I test it and it works, any problem comment it.
Good Luck!
In your Fragment class, in the onCreate() method, you have to call setRetainInstance(true) like this:
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
This tells the FragmentManager to keep your fragments on reloads.
In addition, check your manifest file doesn't have any
android:screenOrientation
config changes where you are basically saying you will handle reloads due to config changes yourself.
In PagerFragment 's onResume() add this:
#Override
public void onResume() {
super.onResume();
for (Fragment fragment : getFragmentManager().getFragments()) {
if (fragment instanceof Tab1Fragment || fragment instanceof Tab2Fragment) {
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.detach(fragment);
ft.attach(fragment);
ft.commit();
}
}
}
Try to add this lines in your code:
public int getItemPosition(Object object) {
return POSITION_NONE;
}
and Add the below lines
pager.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
... anything you may need to do to handle pager state ...
adapter.notifyDataSetChanged(); //this line will force all pages to be loaded fresh when changing between fragments
}
Under
pager.setAdapter(adapter);
Hope this may help you!
Ensure you pass the adapter instance the child fragment manager, not the fragment manager.
Like this:
this._adapter = new PagerAdapter(getChildFragmentManager());
I have a MainActivity and a Fragment called Frags that itself has a fragment called CardFrontFragment.
I register an OnClickListener on this fragment (the child fragment) and in this OnClickListener's OnClick method I replace this fragment(CardFrontFragment) by CardbackFragment fragment. Also I register an OnClickListener on this fragment(CardbackFragment) too, in order to switch again between this to child fragment.
OnClickListener in first fragment (CardfrontFragment) works and the second fragment is shown but now by clicking on the second fragment nothing happens, OnClickListener does not work with the second fragment, this is killing me, please help me!
Code:
MainActivity.java
public class MainActivity extends ActionBarActivity {
public static Frags frag=new Frags();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, frag)
.commit();
}
}
}
Frags.java
public class Frags extends Fragment{
CardBackFragment back=new CardBackFragment();
CardFrontFragment front=new CardFrontFragment();
View view;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view;
view=inflater.inflate(R.layout.frag_layout, container, false);
getChildFragmentManager().beginTransaction()
.add(R.id.frag_container, back)
.commit();
return view;
}
public void Onflip(boolean iSback)
{
if(iSback)
{
getChildFragmentManager().beginTransaction()
.setCustomAnimations(
R.animator.card_flip_right_in, R.animator.card_flip_right_out,
R.animator.card_flip_right_in, R.animator.card_flip_right_out)
.replace(R.id.frag_container, front)
.commit();
}
else
{
getChildFragmentManager().beginTransaction()
.setCustomAnimations(
R.animator.card_flip_right_in, R.animator.card_flip_right_out,
R.animator.card_flip_right_in, R.animator.card_flip_right_out)
.replace(R.id.frag_container, back)
.commit();
}
}
}
CardFrontFragment
public class CardFrontFragment extends Fragment {
public CardFrontFragment() {
}
View view;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view=inflater.inflate(R.layout.fragment_card_front, container, false);
view.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View arg0) {
MainActivity.frag.Onflip(false);
Log.i("front","onclick");
}
});
return view;
}
}
CardBackFragment
public class CardBackFragment extends Fragment {
public CardBackFragment() {
}
View view;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view=inflater.inflate(R.layout.fragment_card_back, container, false);
view.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View arg0) {
MainActivity.frag.Onflip(false);
Log.i("back","onclick");
}
});
return view;
}
}
xml:
fragment_card_front.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#0000ff" >
<Button
android:id="#+id/front_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" />
</LinearLayout>
fragment_card_back.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#000000" >
<Button
android:id="#+id/back_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" />
</LinearLayout>
frag_layout.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="vertical"
android:id="#+id/frag_container">
</LinearLayout>
activity_main.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.demokhar.MainActivity"
tools:ignore="MergeRootFrame" />