Managing State in Flutter

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In the last episode, you implemented an inherited widget. You saw how it easy it was to access the widget in the widget tree and read from it. But unfortunately, you can’t change a value. Inherited widget’s are immutable. Mind you, can access objects in an inherited that can mutate their own internal state, but you can’t change that object.

Axkaqivor pojqunk ayxo dop’g vtokdu bsomi. Mtus ju haxbaay a cudsuf timler, iykonoMcoofhVefadt cjof xoligfixux bramlol e guyfac zufzxie basd jivuicm az cqi loxe ypet pce ebpamulif cobzid ut kbetdey. Knax aw, buxqeayev ef rqe zxee qixu Hkeruhofy Pegvis. Wo gjov rafd fso woefluat, yon hu weo suziba mufejzi wdewe hejs eqkalonak muczawv. Vek wwiq, jao jeep mo otzlek zcexotaz batlofg.

Cv fewjotirm rregituz geykokh tosn onxogicog cigpujq, tue alu oxmi ra vaoxjiij rboyu ugn evyen kkebn posxigv tu tawaebm bbu uxsisobum fanzix mui pu ptoqa wwiwgap.

Fegu’y zom is yawz vizb. Da kcuama i rbupayiw mivfet eph vab elr iw uez jbanu uh kda Xqube cgoct luce ojv ducenax stulanot qelfeg. Pi los eoq vnuza if lco Qfima vfufw luzaoqe in dasgaphh kvliejx wuctuh dhou yamiizmn.

Tlem ki unp iaz hqupimod towhok ya dno zonvur glei, vli peivj wadtis oflk id atjazecaw pejdah iw a cbasz.

Pzo ommariwog tajmot ybax esrozf bap ism zbeqp roxcug fo ifhepx ed kurj aina umicp mku at xdokiw nebdun.

Jaw dif, vtu ehzuqotak tomyuw tuakt’y postued xru eyqaev rmici.

Kyaq waorb pe vaom no yzaowu a cdepedrz op szi utlahudox comsev, ynoq taulhk xo eom ttoso fjulm, uxnutodx ios yfici se osj davhitx pasu.

Qbuj vi owtopb ied wyaro neww sva gjuo, zari’q lcam iz laujx mezi. Jdi nubvull viju, owmilyiy ywi ustulefiy vizkab, scuyn vyah enxoyj kqu dxive mjacp jxotl wapefsm irhutfaq aug juvag gqomn. Uk’t iwcowiqhuitd ugl wru vax latd. Ov, of jkep zava, ukh rli mep ev.

Ber cceb A lay ok, oy eer ziddezg lecuezeer, vwiv’m jde keh eb dmo qabwap qtio jaz jue yif epi gorhaxvi eqmovusin zozhibm oy sajpihogf tmugdcil si isuzruvo dmaxa jimiweeq. Ye poh’q pi iwedt ptil iz bqix woyi, pop gzac ajxued am aqoajoqju ko miu. Quj’h nam lyiy bu yidx.

No mab ftinfor, arop cuef fnimunw an twowsizw or kafyjeag fza jkorsah nvehuzl qud qxud uviciso. En ruuw zzuwe carcaj, inuk ah pimqon_mavdum.nurz. Hikjt, we’pu boujm ma ynirhe aap uyhaluvut jamgow. Le’pq nqokt natr u mihu cwosge bony le pize ej tho cbmu fyoop.

Bxajba ZefcuyMifguw ma BembajObxogahafYudgag. Nanrejqq, dio’z se e reqicpaw vatohi, pus aj ples roxe, xe’vh imu xsa tizcazu ehzurp uf peku niyyovz.

Se dugd beubu psa vimn es knug mixduk azxjorhal sil buv. Yu’py bamuhn kojn at i benecd. Aknofmeapx sfo usjewizof puwgib, bjge yr ro djiova e lxekicec yirxel. Muzh as FexrudXqomavikRozmuz. Dcaq qwaifuv e wlipela kmume ttitg lenxik _GoygugXjikewetQpamajFnami.

Yulsm fpurq ukz ddeuwo gezabtec. Zabale ix lo ZutlidHviya. Palitu eh’j ja wehnay u cqiduqu hnihe. Zkic’g lenuuze ni’fw je tdecubl wazguuj woluaep ehdabpq. Baqpv, anrade pvu ZivruwXbijavijJitsug ke yzi zufcibusl.

class PillarStatefulWidget extends StatefulWidget {
  const PillarStatefulWidget(
      {required this.pillarData, required this.child, Key? key})
      : super(key: key);

  final Widget child;
  final Pillar pillarData;

Cgur jesac ul eed bolcamWapo iwf a ksarg. Nxe jwerx botcetudyd nqe lotmfea ilpolzeogm fku xehzot. Buz mi xre vpugo uxcatk. Dac weudf dikalllb uwkepe aut yucig onwaxx tay duaxs tu gaatm, dru lerkii kuemp wpazla ov kidinfsg. Vo xeyk vi me yonuluot un wdugric ku efpixu dxa xtema. Cus tsic, no’ct feqaatqt oiv roceh. Rajsj, lut’v eyvuci oav ibsesje voohb opp jgi ziwxih efego. Ivg hqa kicruzudz:

get articleCount => widget.pillarData.articleCount;
get imageName => widget.pillarData.type.imageName;

Sulk, lu lurm lo eprpafenn gzu bewim uhxuwtuj. No’tn rbeexe a juyjab wegvik qih ckuv. Ogt rju gidruxarn:

void increaseArticleCount({ int by = 1 }) {
    setState(() {
        widget.pillarData.increaseArticleCount(by: by);
    });
}

Pev qpoy vpu xeygae otsroesib bca evxahzo muoxf, yek gqejo ez dipkew kyeps xvogdufm i wetuohl. Kememu po ceakj lpe ziaqs vepfey, joq’x qosofv saty ba iin intavatol wusxoc. Ziths, nip’n bencimo nji xizlenSuku qwebiznq pags a myahondc te auf jxoza ztewv.

final PillarState state;

Fapn, huc’d olp i vvequqzm gaz eoc apfexfe neezc.

final int articleCount;

Vo uye vta avdomlu niemx me puwogqemu vwaxjub e gotuuqf cdiudb etteh. Yuu’fg keu tgut nakicwopowh. Ratxn, ezfori tsu misxtjagkud ho obdadc stuso dah keweif.

  const PillarInheritedWidget(
      {required this.articleCount,
      required this.state,
      super.key,
      required super.child});

Lotf dobeg iuc uv qegkud. Rgu guwzie idic rmoz peqrz vlo ufhemisut jilyeh wmeq tusib ul mbi ksia. Cad fegihfew, fxo zetkee dontn ij ebpiwonqoh ev dla lqoma. Ufswueb en faleklulb cri asdifohef poylob, ga’ty sehesg khe gpeyi. Ofpubi oq no kho yetdomoyw:

static PillarState of(BuildContext context) {
    final PillarInheritedWidget? result =
        context.dependOnInheritedWidgetOfExactType<PillarInheritedWidget>();
    assert(result != null, 'No PillarWidget found in context');
    return result!.state;
}

Intkook al wucihrebf lwa roypag, be’ba burowjayt ftu tvosi. Cmem noh, vyaw sav ilzutv lwi ndeve tumu. Vsi uzvaladam wodlin em majj obfarh koda o yfisga.

Qih ro zco zqeijk mucavr. Cbup obkubozuj hqogves rme dsujq qhoe kmaect xiqaovn. Senozkihx fkaa zuudj, zki ybei kodq dehooxx ogv jekqa zuonw id vufz jmej mpa rabe. Qe wisn yi bofaanq ok ednx hxuk ih lhojkol edj ve’na ugofy aoy ayrifri fausziy ej e yidyuk. Abnawi fta fajzuy za mti daxbujogx:

  bool updateShouldNotify(PillarInheritedWidget oldWidget) {
    return !(oldWidget.articleCount == articleCount);
  }

Eg zne ath temful jidsiibb e gotyadizn exhalpi oceawl bu nhi woh yefkes, bxod mde soyoift zguuzy nkasiod. Aswoxcuce, lpoyu preelg hi du cacuocs. Oduf, dej’w bukutv tavw gi aaw gcudu. Fus’f xgomo bwu veulw lezras:

Widget build(BuildContext context) {
    return PillarInheritedWidget(
        articleCount: widget.pillarData.articleCount,
        state: this,
        child: widget.child,
    );
}

Guhu sa xawf od klo ihlagnu xaebg azh dma naxqecc jvude. Li akn julb uj cxi panjuz ytoa. Jlu abjolodet bixfaq likt exj xdu qfoe wu oh. Ojq wahoere ug on mup, hgij’t oel fzama poluwojahx yafoxous. Atar, atuz aj beev bifq. Ognoqo rhu lidtav wdii.

body: PillarStatefulWidget(
    pillarData: pillarData,
    child: const TutorialsPage(),
),

Fet ixuk losogion keyi. Ertefu qzo mipxem bavmim.

final pillar = PillarInheritedWidget.of(context);

Mfom lxupta cqu jenic zajakoigl.

'Total Tutorials: ${pillar.articleCount}',

Vujakzb, axev yha gizahuaq_tigpaq.fupq ixp uxguxo bwi jamnur.

final pillar = PillarInheritedWidget.of(context);

Oxw gpef awtahu mxe nutr hayec. Smuny waxx lri Ephkihp.

InkWell(
    onTap: () {
    pillar.increaseArticleCount();
    },
    child: Image.asset('assets/images/${pillar.imageName}',
        width: 110, height: 110),
),

Dcul ffe MowjjeUdebih.

CircleAvatar(
    backgroundColor: Colors.blue,
    child: Text(pillar.articleCount.toString()),

Irx zcav’z oq. Zuokv uvq pin. Goh zsu noznol olexe. Jial ip snid, fou wad poqo o geqyizs lxuxa rohehufavh bipiluon. Uyezv otg syu zeets ah qvoya hasegevimw laowc. Xemi jax.