I have a fragment in my Photo app. When the user edits photo,
I start an AsyncTask to compress the image in the background which will return compressed image bytes.
In postExecute() i call an editComplete method which will update my data model with compressed image bytes
Once it is done, i call getParentFragmentManager to popBackStack to remove the edit mode to gallery mode
Here while calling getParentFragmentManager() i am getting IllegalStateException: "Fragment " + this + " not associated with a fragment manager."
My Fragment Async task:
protected class CompressBitmapImageTask extends AsyncTask<Void, Void, byte[]>
{
private Bitmap editedImageBitmap;
private BitmapDownscale bitmapDownscale;
CompressBitmapImageTask(Bitmap editedImageBitmap, BitmapDownscale bitmapDownscale)
{
this.editedImageBitmap = editedImageBitmap;
this.bitmapDownscale = bitmapDownscale;
}
#Override
protected byte[] doInBackground(Void... params)
{
BitmapDownscale.BitmapDownscaleResult result = bitmapDownscale.downscaleFromBitmap(editedBitmap, true);
return result.bitmapBytes;
}
#Override
protected void onPostExecute(byte[] bytes)
{
onEditImageComplete(bytes);
}
}
protected void onEditImageComplete(#Nullable byte[] editedBitmapData)
{
if (editedBitmapData != null)
photoModel.editedBitmapData = editedBitmapData;
getParentFragmentManager().popBackStack();
}
I am getting exception when calling getParentFragmentManager(). I referred a related post, Fragment MyFragment not attached to Activity
But that is related to fragment not being associated with activity. So i am not sure if adding isAdded() would solve the problem in my case.
Ideally, i need to make sure that fragmentManager is not null while i try to pop backStack(). Only method that does is isStateSaved() in androidx.fragment.app.Fragment but i don't think that is an appropriate method.
Can somebody point me in right direction?
After further reading Android docs on Fragment Manager and this answer Fragment MyFragment not attached to Activity, i believe that isAdded() check is the way to confirm whether the fragment is associated with the activity through fragmentManager. It was confusing looking at the definition of the method at first,
/**
* Return true if the fragment is currently added to its activity.
*/
final public boolean isAdded() {
return mHost != null && mAdded;
}
Because it says that whether the host is not null and if the fragment is added. I think the key is mAdded which tells us whether the fragment is added to fragment Manager. So i updated my popstack logic with a check,
protected void onEditImageComplete(#Nullable byte[] editedBitmapData)
{
if (editedBitmapData != null)
photoModel.editedBitmapData = editedBitmapData;
if (isAdded())
getParentFragmentManager().popBackStack();
} ```
I am using a bottom navigation bar in my MainActivity to handle some fragments. This is the code used for switching between them:
private val mOnNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
if (item.isChecked &&
supportFragmentManager.findFragmentById(R.id.act_main_fragment_container) != null
)
return#OnNavigationItemSelectedListener false
val fragment =
when (item.itemId) {
R.id.navigation_home -> fragments[0]
R.id.navigation_bookings -> fragments[1]
R.id.navigation_messages -> fragments[2]
R.id.navigation_dashboard -> fragments[3]
R.id.navigation_profile -> fragments[4]
else -> fragments[0]
}
this replaceWithNoBackStack fragment
return#OnNavigationItemSelectedListener true
}
the method replaceWithNoBackstack is just a short-hand for this:
supportFragmentManager
?.beginTransaction()
?.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
?.replace(containerId, fragment)
?.commit()
The problem is that when i switch faster between them, my app crashes with the following exception:
java.lang.IllegalStateException: Restarter must be created only during owner's initialization stage
at androidx.savedstate.SavedStateRegistryController.performRestore(SavedStateRegistryController.java:59)
at androidx.fragment.app.Fragment.performCreate(Fragment.java:2580)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:837)
at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1237)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1302)
at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)
at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2075)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1865)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1820)
at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1726)
at androidx.fragment.app.FragmentManagerImpl$2.run(FragmentManagerImpl.java:150)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6709)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769)
I've been searching a lot and couldn't find an answer.
I also got this error if I do an API call, put the app in background, wait for the response, and at the time I go back to the app, the app crashes because I am trying to display a dialog fragment immediately (the reason I think this is happening is that the transaction of recreating the fragment when coming back from the background is still in progress at the time of displaying the dialog fragment). I solved this in a hacky way by setting a 500ms delay for the dialog because I couldn't figure out other solutions.
Please ask if you need more details regarding this.
Thank you in advance!
POSSIBLE TEMP SOLUTIONS
EDIT
I solved this issue by downgrading the app compat depedency to androidx.appcompat:appcompat:1.0.2 but this is just a temporary solution, since i will have to update it in future. I'm hoping someone will figure it out.
EDIT 2
I solved the issue by removing setTransition() from fragment transactions. At least I know the reason why android apps does not have good transitions in general
EDIT 3
Maybe the best solution to avoid this issue and also make things work smoothly is just to use ViewPager to handle bottom bar navigation
because the version 1.0.0 has not check the state, so it will not throw the exception,
but the version 1.1.0 changes the source code，so it throws the exception.
this is the Fragment version-1.1.0 source code, it will invoke the method performRestore
void performCreate(Bundle savedInstanceState) {
if (mChildFragmentManager != null) {
mChildFragmentManager.noteStateNotSaved();
}
mState = CREATED;
mCalled = false;
mSavedStateRegistryController.performRestore(savedInstanceState);
onCreate(savedInstanceState);
mIsCreated = true;
if (!mCalled) {
throw new SuperNotCalledException("Fragment " + this
+ " did not call through to super.onCreate()");
}
mLifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE);
}
/**
the exception
**/
public void performRestore(#Nullable Bundle savedState) {
Lifecycle lifecycle = mOwner.getLifecycle();
if (lifecycle.getCurrentState() != Lifecycle.State.INITIALIZED) {
throw new IllegalStateException("Restarter must be created only during "
+ "owner's initialization stage");
}
lifecycle.addObserver(new Recreator(mOwner));
mRegistry.performRestore(lifecycle, savedState);
}
this is the version-1.0.0 source code，did not invoke the performRestore,so will not throw the exception
void performCreate(Bundle savedInstanceState) {
if (mChildFragmentManager != null) {
mChildFragmentManager.noteStateNotSaved();
}
mState = CREATED;
mCalled = false;
onCreate(savedInstanceState);
mIsCreated = true;
if (!mCalled) {
throw new SuperNotCalledException("Fragment " + this
+ " did not call through to super.onCreate()");
}
mLifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE);
}
There are two different solution which can handle this:
The first solution is to split the transaction。
Because we always use replace or merge remove and add into one Transaction.
We can split the transaction to two transaction like this:
FragmentTransaction ft = manager.beginTransaction();
Fragment prev = manager.findFragmentByTag(tag);
if (prev != null) {
//commit immediately
ft.remove(prev).commitAllowingStateLoss();
}
FragmentTransaction addTransaction = manager.beginTransaction();
addTransaction.addToBackStack(null);
addTransaction.add(layoutId, fragment,
tag).commitAllowingStateLoss();
because this two transaction will be two different Message which will be handled by Handler.
The second solution is check the state in advance.
we can follow the source code，check the state in advance
FragmentTransaction ft = manager.beginTransaction();
Fragment prev = manager.findFragmentByTag(tag);
if (prev != null) {
if (prev.getLifecycle().getCurrentState() != Lifecycle.State.INITIALIZED) {
return;
}
ft.remove(prev);
}
I recommend the first way,because the second way is folowing the source code,if the source
code change the code, it will be invalid。
I had the same problem.
val fragment = Account.activityAfterLogin
val ft = activity?.getSupportFragmentManager()?.beginTransaction()
//error
ft?.setCustomAnimations(android.R.anim.slide_in_left,android.R.anim.slide_out_right)0
ft?.replace(R.id.framelayout_account,fragment)
ft?.commit()
Changing the library version did not help.
I solved this by adding the ft?.AddToBackStack(null) line after the ft?.setCustomAnimations () method and that’s it.
Animation works and there are no crashes.
If you're using 'androidx.core:core-ktx:1.0.2',
try changing to 1.0.1
If you're using lifecycle(or rxFragment) and androidx_appcompat:alpha05, try changeing versio.
ex) appcompat : 1.1.0-beta01 or 1.0.2
I think's that it appears as an error when saving the state when the target fragment is reused (onPause-onResume).
I changed implementation to api for androidx.appcompat:appcompat:1.0.2 and its worked for me
If it can help, I have encountered the same issue with a BottomNavigationView and setCustomAnimations, basically by switching quickly between Fragments, you may end up starting a FragmentTransaction while the previous one has not finished and then it crashes.
To avoid that, I disable the Navigation Bar until the transition is finished. So I have created a method to enable/disable the BottomNavigationView items (disabling the BottomNavigationView itself does not disable the menu or I didn't find the way) and then I re-enable them once the transition is completed.
To disable the items I call the following method right before starting a FragmentTransition:
public void toggleNavigationBarItems(boolean enabled) {
Menu navMenu = navigationView.getMenu();
for (int i = 0; i < navMenu.size(); ++i) {
navMenu.getItem(i).setEnabled(enabled);
}
}
To re-enable them, I have created an abstract Fragment class for the Fragments loaded from the BottomNavigationView. In this class, I overrides onCreateAnimator (if you use View Animation you should override onCreateAnimation) and I re-enable them onAnimationEnd.
#Nullable
#Override
public Animator onCreateAnimator(int transit, boolean enter, int nextAnim) {
if(enter){ // check the note below
Animator animator = AnimatorInflater.loadAnimator(getContext(), nextAnim);
animator.addListener(new AnimatorListenerAdapter() {
#Override
public void onAnimationEnd(Animator animation) {
myActivity.toggleNavigationBarItems(true)
}
});
return animator;
}
return super.onCreateAnimator(transit, enter, nextAnim);
}
Note: as my enter and exit animations have the same duration, I don't need to synchronise them as the enter animation starts after the exit one. That's why the if (enter) is sufficient.
I fixed this problem with add 'synchronized' into add fragment method
before :
public void addFragment(int contentFrameId, Fragment fragment, Bundle param, boolean addToStack) {
try {
if (!fragment.isAdded()) {
if (param != null) {
fragment.setArguments(param);
}
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction()
.add(contentFrameId, fragment)
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
if (addToStack)
fragmentTransaction.addToBackStack(fragment.getClass().toString());
fragmentTransaction.commit();
}
} catch (IllegalStateException e) {
handleError(e.getMessage());
} catch (Exception e) {
handleError(e.getMessage());
}
}
after :
public synchronized void addFragment(int contentFrameId, Fragment fragment, Bundle param, boolean addToStack) {
try {
if (!fragment.isAdded()) {
if (param != null) {
fragment.setArguments(param);
}
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction()
.add(contentFrameId, fragment)
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
if (addToStack)
fragmentTransaction.addToBackStack(fragment.getClass().toString());
fragmentTransaction.commit();
}
} catch (IllegalStateException e) {
handleError(e.getMessage());
} catch (Exception e) {
handleError(e.getMessage());
}
}
This bug seems to be resolved using androidx.appcompat:appcomat:1.1.0-rc01 and androidx.fragment:fragment:1.1.0-rc03
https://developer.android.com/jetpack/androidx/releases/fragment#1.1.0-rc03
I have this issue when using setCustomAnimations.
by removing setCustomAnimations solved my problem.
also I have no problem when I create new instance of fragment before showing it even using setCustomAnimation.
EDIT: another way is adding fragment to backstack.
I was able to fix this (hopefully 😃) by using commitNow() instead of commit() for all bottom nav fragment transactions.
I like this approach better as it allows you to still use custom transitions between fragments.
Note: This is a solution only if you don't want your bottom nav transactions to be added to backstack (which you should not be doing anyways).
Nothing worked except Drown Coder's solution, but it was still not perfect, because it adds transactions to backstack. So if you press all buttons in bottom navigation, you have at least 1 of every fragment in backstack. I slightly improved this solution, so you don't use .replace() that crashes app whith thansaction animations.
Here is the code:
if (getChildFragmentManager().getBackStackEntryCount() > 0) {
getChildFragmentManager().popBackStack();
}
FragmentTransaction addTransaction = getChildFragmentManager().beginTransaction();
addTransaction.setCustomAnimations(R.animator.fragment_fade_in, R.animator.fragment_fade_out);
addTransaction.addToBackStack(null);
addTransaction.add(R.id.frame, fragment, fragment.getClass().getName()).commitAllowingStateLoss();
I found another way of creating this case.
CASE-1
Inflate a fragment in frame-layout at an activity
start an API request (don't consume the api response when app in foreground)
Keep your app in background
Consume the API request (suppose you want to add another fragment on api response)
Inflate another fragment using .replace() method on the same frame-layout
You will be able to create the Crash
CASE-2
Inflate a fragment in frame-layout at an activity
Start an API request
Consume the api in foreground (suppose you want to add another fragment on api response, using .replace() method of fragment-manager)
Put your app in background
Recreate your application (you can do this using "Don't keep activities", changing permission, changing system language)
Come back to your application
Your activity will start re-creating
Activity will auto recreate its already inflated fragment suppose it is of (point-1)
Make sure API is request again in on recreate case, after point-8
Consume API response and inflate another fragment using .replace() method
You will be able to create the Crash (As in this case, already a transition is running point-8, and you are adding another fragment at point-10)
I have a viewpager in an activity. I'm loading it like this
ArrayList<Fragment> arrayListFragment = new ArrayList<>();
Fragment first = Fragment.instantiate(MainActivity.this, MainActivityFragment.class.getName());
Fragment second = Fragment.instantiate(MainActivity.this, SecondFragment.class.getName());
arrayListFragment.add(first);
arrayListFragment.add(second);
Log.d(TAG, "Pager created " + second);
mPagerAdapter = new SwipeScreenPagerAdapter(getSupportFragmentManager(),
arrayListFragment, pageTitles); //This is custom adapter
And In onCreateView() of SecondFragment I've this log:
mAdapter = new CustomAdapter(mContext, null, mList);
Log.d(TAG, "Initialised adapter " + this);
Everything works fine when I run the app. The interesting thing happen when I put app in background and then resume it after some time. The activity is restarted and viewpager is initialised again and for some reason Log.d(TAG, "Pager created " + second); and Log.d(TAG, "Initialised adapter " + this); statements print fragment with different ids. They both print same id on the first run but differ when i resume. And mAdapter becomes null when used in a fragment function (because this function is called on fragment received from viewpager).
Log statements are :
Pager created SecondFragment{269ef202}
Initialised adapter SecondFragment{298444fe #2 id=0x7f0e0084 android:switcher:2131624068:1}
From where this new fragment is being created? At first I thought it is somehow restoring the old fragment but I tried passing null in onActivityCreate like this:
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(null);
}
but it is still creating separate fragment instance and also it has different id.
I figured out the problem. When the app was resumed, activity was restoring the fragment that was last associated with it in the call
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
so passing null to super.onCreate(null) caused it to avoid restoring last fragment. In my case I needed to create new copy of fragment because my data need to be refetched on every time activity was created so set it null with caution.
Given a fragment which loads (a lot of) data from the database using a loader.
Problem :
I have a pager adapter which destroys the fragment when the user moves away from the tab holding it and recreates it when user gets back to that tab. Because of this recreation, a new loader is created everytime and the data gets loaded everytime.
Question :
To avoid recreating loader everytime the fragment is created, is it ok to use getActivity.getSupportLoaderManager.initLoader(loaderId, null, false) in the onActivityCreated method of the fragment?
I have tried it, tested it and it seems to be working fine. But I'm not convinced that it is right.
Actually, checking the source code, you end up doing the same.
Fragment.getLoaderManager:
/**
* Return the LoaderManager for this fragment, creating it if needed.
*/
public LoaderManager getLoaderManager() {
if (mLoaderManager != null) {
return mLoaderManager;
}
if (mActivity == null) {
throw new IllegalStateException("Fragment " + this + " not attached to Activity");
}
mCheckedForLoaderManager = true;
mLoaderManager = mActivity.getLoaderManager(mWho, mLoadersStarted, true);
return mLoaderManager;
}
mWho is basically the fragment ID.
final void setIndex(int index, Fragment parent) {
mIndex = index;
if (parent != null) {
mWho = parent.mWho + ":" + mIndex;
} else {
mWho = "android:fragment:" + mIndex;
}
}
The difference in Activity.getLoaderManager() is that who will be (root)
So even though you can do what you are asking, calling it directly from the Fragment might be a better approach
Activity source code
Fragment source code
Disclaimer: I only checked the source code in the latest version, but I don't expect it to be very different
May i ask why you are simply not retaining the Fragment? It seems that what you need is to create the Loader in the Fragment and create the fragment with setRetainInstance(true).
In this case remember to provide a TAG when you add the fragment.
This way the fragment will survive even to activity config changes and only the view will be recreated leaving your loader alive.
I wrote Android JUnit test for Activity that instantiates fragments (actually tabs). During the test, when I try to do anything with these tabs, they crash because getActivity() method in them returns null. The actual application (not a test) never shows this behavior and fragment getActivity() always returns the right parent activity there. My test case looks like:
public class SetupPanelTest extends ActivityUnitTestCase<MyAct> {
FSetup s;
public SetupPanelTest() {
super(MyAct.class);
}
protected void setUp() throws Exception {
super.setUp();
startActivity(new Intent(), null, null);
final MyAct act = getActivity();
AllTabs tabs = act.getTabs();
String tabname = act.getResources().getString(R.string.configuration);
// This method instantiates the activity as said below
s = (FSetup) tabs.showTab(tabname);
FragmentManager m = act.getFragmentManager();
// m.beginTransaction().attach(s).commit();
// ... and even this does not help when commented out
assertTrue(s instanceof FSetup); // Ok
assertEquals(act, s.getActivity()); // Failure
}
public void testOnPause() {
// this crashes because s.getActivity == null;
s.onPause();
}
}
The AllTabs creates a fragment, then required, in this way:
FragmentManager manager = getFragmentManager();
Fragment fragment = manager.findFragmentByTag(tabname);
if (fragment == null || fragment.getActivity() == null) {
Log.v(TAG, "Instantiating ");
fragment = new MyFragment();
manager.beginTransaction().replace(R.id.setup_tab, fragment, tabname).commit();
....
Here, all fragments are initially placeholders that are later replaced by the actual fragments:
<FrameLayout
android:id="#+id/setup_tab"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
The logcat shows that the new fragment has been instantiated. In the same layout, there is also the previously mentioned AllTabs fragment that seems not having this problem (where and how it gets FragmentManager otherwise):
<TabWidget
android:id="#android:id/alltabs"
...
Most impressively, when I call attach directly on the fragment manager obtained on the right activity, this still has no effect. I tried to put five seconds delay (I have read that transaction may be delayed), I tried to call the rest of the test through runOnUiThread - nothing helps.
The question is that is need to do so to attach my fragments to the activity also during the test. I have fragment and I have activity, I cannot attach one to another.
Even if you call .commit() on transaction, it is still not done, fragments are attached only lazily.
FragmentManager m = activity.getFragmentManager();
m.executePendingTransactions();
This finally attaches all fragments to the activity. Seems redundant when running the application itself but required in JUnit test case.