Encountering the dreaded “IllegalStateException: Tin not execute this act last onSaveInstanceState” successful your Android improvement travel tin beryllium extremely irritating. This objection usually arises once you effort to perpetrate a FragmentTransaction last the act’s government has been saved, frequently starring to app crashes and a disrupted person education. Knowing the lifecycle of an Act and Fragment, and however government redeeming performs a important function, is cardinal to stopping this communal mistake. Successful this blanket usher, we’ll delve into the intricacies of this objection, exploring its base causes, effectual prevention methods, and sturdy options to guarantee a creaseless and clang-escaped education for your customers.
Knowing the onSaveInstanceState() Mechanics
The onSaveInstanceState() technique is a captious portion of the Android act lifecycle. It’s known as by the scheme earlier an act is quickly destroyed, specified arsenic throughout a configuration alteration (surface rotation) oregon once the scheme wants to reclaim assets. This methodology permits the act to prevention its actual government, together with the government of its fragments, into a Bundle entity. This Bundle is past utilized to reconstruct the act’s government once it’s recreated.
The job happens once you effort to perpetrate a FragmentTransaction last onSaveInstanceState() has been known as. Astatine this component, the scheme has already taken a snapshot of the act’s government, and immoderate consequent modifications to the FragmentManager tin pb to inconsistencies and finally, the IllegalStateException.
Android developer documentation explicitly warns in opposition to performing FragmentTransactions last onSaveInstanceState(): “This is due to the fact that the government of the act is already saved, truthful immoderate modifications you brand volition beryllium mislaid if the act wants to beryllium restored.”
Communal Eventualities Starring to the Objection
Respective communal eventualities tin set off this objection. 1 predominant perpetrator is performing asynchronous operations, similar web requests, that absolute last the act has been paused oregon stopped. If the consequence of specified an cognition triggers a FragmentTransaction, it tin pb to the mistake if the act’s government has already been saved.
Different communal origin is dealing with configuration adjustments improperly. Once the surface rotates, for case, the act is destroyed and recreated. If you’re committing FragmentTransactions successful consequence to configuration adjustments with out decently accounting for the act lifecycle, you’re apt to brush the IllegalStateException.
Present are any circumstantial examples:
- Updating UI components inside a Fragment last the Act’s government is saved.
- Changing Fragments based mostly connected information obtained from a inheritance thread.
- Committing FragmentTransactions successful
onStop()oregononDestroy().
Effectual Prevention Methods
Stopping this objection entails cautiously managing FragmentTransactions inside the act lifecycle. A communal resolution is to usage isFinishing() inside your Act to cheque if the act is successful the procedure of being completed. If it is, debar committing immoderate FragmentTransactions.
Different effectual attack is to perpetrate transactions inside onResumeFragments(). This methodology is referred to as last onResume() and ensures that the FragmentManager is disposable and fit to grip transactions. This is peculiarly utile once restoring the government of fragments last a configuration alteration.
For asynchronous operations, guarantee you cheque the act’s government earlier committing immoderate FragmentTransactions primarily based connected the cognitionβs consequence. You tin usage isAdded() inside your fragment to cheque if itβs presently hooked up to an act.
Strong Options and Workarounds
If unavoidable conditions originate, see utilizing commitAllowingStateLoss(). Piece this technique permits you to perpetrate transactions equal last onSaveInstanceState(), it’s important to realize the possible implications. Arsenic the sanction suggests, utilizing this methodology mightiness consequence successful government failure if the act wants to beryllium restored. Usage it judiciously and lone arsenic a past hotel.
Presentβs an ordered database of advisable steps to resoluteness the content:
- Analyse your codification to place the direct component wherever the FragmentTransaction is being dedicated.
- Cheque if the transaction happens last
onSaveInstanceState(). Make the most of lifecycle strategies similaronPause()andonStop()for debugging. - Instrumentality the preventative measures mentioned supra, prioritizing
isFinishing()andonResumeFragments(). - If essential, see utilizing
commitAllowingStateLoss()with warning, knowing the possible for government failure.
See leveraging a sturdy case autobus scheme to decouple connection betwixt parts and debar nonstop Fragment manipulation from inheritance threads. This tin aid forestall eventualities wherever transactions are triggered astatine inappropriate instances.
FAQ: Communal Questions astir IllegalStateException
Q: What is the capital origin of the “IllegalStateException: Tin not execute this act last onSaveInstanceState”?
A: Making an attempt to perpetrate FragmentTransactions last the act’s government has been saved, normally done onSaveInstanceState(), is the capital origin. This frequently occurs throughout asynchronous operations oregon mishandling configuration modifications.
Q: However tin I forestall this objection?
A: The about effectual prevention methods see utilizing isFinishing() to cheque the act’s government, committing transactions inside onResumeFragments(), and cautiously managing transactions triggered by asynchronous operations.
By knowing the lifecycle of Actions and Fragments and implementing these methods, you tin make much sturdy and unchangeable Android functions, escaped from the vexation of the “IllegalStateException: Tin not execute this act last onSaveInstanceState” objection. This proactive attack volition pb to a importantly improved person education and trim improvement clip spent connected debugging crashes. Research sources similar the authoritative Android documentation and Stack Overflow for additional insights and assemblage activity. Retrieve to prioritize person education by dealing with these situations gracefully and offering informative mistake messages once essential. For much successful-extent accusation connected Android improvement champion practices, cheque retired Android Builders documentation connected Fragment lifecycle, Stack Overflow for applicable questions and solutions, and Vogella’s tutorial connected Android Fragments.
Question & Answer :
I person a Unrecorded Android exertion, and from marketplace i person obtained pursuing stack hint and i person nary thought wherefore its taking place arsenic its not occurring successful exertion codification however its getting brought about by any oregon the another case from the exertion (presumption)
I americium not utilizing Fragments, inactive location is a mention of FragmentManager. If immoderate assemblage tin propulsion any airy connected any hidden info to debar this kind of content:
java.lang.IllegalStateException: Tin not execute this act last onSaveInstanceState astatine android.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1109) astatine android.app.FragmentManagerImpl.popBackStackImmediate(FragmentManager.java:399) astatine android.app.Act.onBackPressed(Act.java:2066) astatine android.app.Act.onKeyDown(Act.java:1962) astatine android.position.KeyEvent.dispatch(KeyEvent.java:2482) astatine android.app.Act.dispatchKeyEvent(Act.java:2274) astatine com.android.inner.argumentation.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1668) astatine android.position.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112) astatine android.position.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112) astatine android.position.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112) astatine android.position.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112) astatine android.position.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112) astatine android.position.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112) astatine com.android.inner.argumentation.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1720) astatine com.android.inner.argumentation.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1258) astatine android.app.Act.dispatchKeyEvent(Act.java:2269) astatine com.android.inner.argumentation.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1668) astatine android.position.ViewRoot.deliverKeyEventPostIme(ViewRoot.java:2851) astatine android.position.ViewRoot.handleFinishedEvent(ViewRoot.java:2824) astatine android.position.ViewRoot.handleMessage(ViewRoot.java:2011) astatine android.os.Handler.dispatchMessage(Handler.java:ninety nine) astatine android.os.Looper.loop(Looper.java:132) astatine android.app.ActivityThread.chief(ActivityThread.java:4025) astatine java.lang.indicate.Methodology.invokeNative(Autochthonal Methodology) astatine java.lang.indicate.Technique.invoke(Technique.java:491) astatine com.android.inner.os.ZygoteInit$MethodAndArgsCaller.tally(ZygoteInit.java:841) astatine com.android.inner.os.ZygoteInit.chief(ZygoteInit.java:599) astatine dalvik.scheme.NativeStart.chief(Autochthonal Methodology)
This is the about anserine bug I person encountered truthful cold. I had a Fragment exertion running absolutely for API < eleven, and Unit Closing connected API > eleven.
I truly couldn’t fig retired what they modified wrong the Act lifecycle successful the call to saveInstance, however I present is however I solved this :
@Override protected void onSaveInstanceState(Bundle outState) { //Nary call for ace(). Bug connected API Flat > eleven. }
I conscionable bash not brand the call to .ace() and the whole lot plant large. I anticipation this volition prevention you any clip.
EDIT: last any much investigation, this is a recognized bug successful the activity bundle.
If you demand to prevention the case, and adhd thing to your outState Bundle you tin usage the pursuing :
@Override protected void onSaveInstanceState(Bundle outState) { outState.putString("WORKAROUND_FOR_BUG_19917_KEY", "WORKAROUND_FOR_BUG_19917_VALUE"); ace.onSaveInstanceState(outState); }
EDIT2: this whitethorn besides happen if you are attempting to execute a transaction last your Act is gone successful inheritance. To debar this you ought to usage commitAllowingStateLoss()
EDIT3: The supra options have been fixing points successful the aboriginal activity.v4 libraries from what I tin retrieve. However if you inactive person points with this you Essential besides publication @AlexLockwood ’s weblog : Fragment Transactions & Act Government Failure
Abstract from the weblog station (however I powerfully urge you to publication it) :
- Ne\’er
perpetrate()transactions lastonPause()connected pre-Honeycomb, andonStop()connected station-Honeycomb - Beryllium cautious once committing transactions wrong
Actlifecycle strategies. UsageonCreate(),onResumeFragments()andonPostResume() - Debar performing transactions wrong asynchronous callback strategies
- Usage
commitAllowingStateLoss()lone arsenic a past hotel
