Anomalia durante la modifica manuale del savedInstanceState di un ViewPager Fragment

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Salve a tutti, ho aperto una discussione su stackoverflow ma non ho ricevuto risposta.

Incollo qui la mia domanda che ho fatto lì.

Se ci sono problemi con il fatto che il seguente testo è in inglese vi prego di farmelo sapere, lo traduco senza alcun problema!

I have a ViewPager (instantiated with FragmentStatePagerAdapter) with some Fragment attached to it.

In a specific usecase I need to reset instanceBean and UI for most of the fragments in the pager.

After some googling I have tried some solutions like this but the side effects were not easy manageable. Other solution like this doesn't match my needs.

So I decided to go straight with the manual reset of the UI and instanceBean obj like in the code below:

The code

Single fragment reset

public void initFragment() {<br /> n<span class="forTooltip">ot</span>aBean = new N<span class="forTooltip">ot</span>eFragmentTO();<br /> <br /> f<span class="forTooltip">rom</span>SpinnerListener = false;<br /> }<br /> <br /> public void resetFragment() {<br /> initFragment();<br /> NoteFragment.retainInstanceState = false;<br /> }

 

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    public void initFragment() {

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        notaBean = new NoteFragmentTO();

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        fromSpinnerListener = false;

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    }

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    public void resetFragment() {

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        initFragment();

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        NoteFragment.retainInstanceState = false;

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    }

This is done with the following code from the parent Activity:

Fragment reset from parent

private void resetAfterSaving() {<br /> mIndicator.setCurrentItem(POSITION_F*****);<br /> f*****Info.resetFragment();<br /> <br /> mIndicator.setCurrentItem(POSITION_NOTE);<br /> noteInfo.resetFragment();<br /> <br /> mIndicator.setCurrentItem(POSITION_M*****);<br /> m*****Info.resetFragment();<br /> <br /> mIndicator.setCurrentItem(POSITION_V*****);<br /> v*****.resetFragment();<br /> }

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        private void resetAfterSaving() {

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        mIndicator.setCurrentItem(POSITION_F*****);

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        f*****Info.resetFragment();

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        mIndicator.setCurrentItem(POSITION_NOTE);

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        noteInfo.resetFragment();

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        mIndicator.setCurrentItem(POSITION_M*****);

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        m*****Info.resetFragment();

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        mIndicator.setCurrentItem(POSITION_V*****);

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        v*****.resetFragment();

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    }

AfterViews method:

@AfterViews<br /> public void afterView() {<br /> if (mSavedInstanceState != null) {<br /> restoreState(mSavedInstanceState);<br /> }<br /> <br /> NoteFragment.retainInstanceState = true;<br /> <br /> // Inits the adapters<br /> noteAdapter = new NoteArrayAdapter(this, noteDefaultList);<br /> <br /> sp_viol_nota_default.setAdapter(noteAdapter);<br /> //sp_viol_nota_default.seton<br /> <br /> et_viol_nota.setOnFocusChangeListener(new OnFocusChangeListener() {<br /> <br /> @Override<br /> public void onFocusChange(View v, boolean hasFocus) {<br /> if (!hasFocus) {<br /> String readText = et_viol_nota.getText().toString().trim();<br /> <br /> notaBean.setNota(readText == "" ? null : readText);<br /> }<br /> }<br /> });<br /> }

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        @AfterViews

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        public void afterView() {

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            if (mSavedInstanceState != null) {

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                restoreState(mSavedInstanceState);

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            }

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            NoteFragment.retainInstanceState = true;

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            // Inits the adapters

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            noteAdapter = new NoteArrayAdapter(this, noteDefaultList);

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            sp_viol_nota_default.setAdapter(noteAdapter);

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            //sp_viol_nota_default.seton

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            et_viol_nota.setOnFocusChangeListener(new OnFocusChangeListener() {

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                @Override

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                public void onFocusChange(View v, boolean hasFocus) {

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                    if (!hasFocus) {

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                        String readText = et_viol_nota.getText().toString().trim();

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                        notaBean.setNota(readText == "" ? null : readText);

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                    }

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                }

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            });

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        }

OnSavedInstanceState

@Override<br /> public void onSaveInstanceState(Bundle outState) {<br /> super.onSaveInstanceState(outState);<br /> <br /> outState.putParcelableArrayList(KEY_NOTE_D_LIST, (ArrayList<VlzAnagraficaNoteagente>) noteDefaultList);<br /> outState.putInt(KEY_NOTE_D_POSITION, !NoteFragment.retainInstanceState ? 0 : notePosition);<br /> <br /> notaBean.setNota(!NoteFragment.retainInstanceState ? "" : et_viol_nota.getText().toString().trim());<br /> outState.putParcelable(NoteFragmentTO.INTENT_KEY, notaBean);<br /> }

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    @Override

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    public void onSaveInstanceState(Bundle outState) {

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        super.onSaveInstanceState(outState);

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        outState.putParcelableArrayList(KEY_NOTE_D_LIST, (ArrayList<VlzAnagraficaNoteagente>) noteDefaultList);

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        outState.putInt(KEY_NOTE_D_POSITION, !NoteFragment.retainInstanceState ? 0 : notePosition);

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        notaBean.setNota(!NoteFragment.retainInstanceState ? "" : et_viol_nota.getText().toString().trim());

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        outState.putParcelable(NoteFragmentTO.INTENT_KEY, notaBean);

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    }

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Why do I set every page before resetting them?

Because like explained here:

When pages are not visible to the user, their entire fragment may be destroyed, only keeping the saved state of that fragment.

and because until I don't select the relative fragment the @AfterViews method (that is everything processed right after OnCreateView of the fragment) is not executed.
This throws NullPointerException for a thousand of reason (Usually in the @AfterViews method You launch RestoreState method, initializes adapter, do UI stuff).

Setting the relative page before the reset let @AfterViews method be processed.


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Before checking what would happened when rotating the device, all the fragment I need are correcly reset.

When rotating the device, the error comes out:

The views (mainly EditText) go back to their previous state BEFORE my reset.


What happens?

When switching between the page, at a certain point the page will be destroyed and OnSavedInstanceState is called everytime for each page.

I have already handled the OnSavedInstanceState (like above) that when the boolean is false saves the state like if it had just been created.

I found that until within AfterView method the EditText has its text set to blank (like I want) but going on with the debug the EditText goes back to its previous state, so at the end it will show the last text it had.

Question

How can I keep the manually set (in OnSavedInstanceState) EditText text after destroying/recreating a fragment?

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