Recomposition

Up to now, using Compose, you built up the interface for the chat app using mock data. It’s like you made the yummy-looking but completely fake cake some stores display. But you want to have your cake and eat it too! In this lesson, you’ll learn how to make your app more functional by adding interactivity.

You need to do two main things to make the chat interface interactive. First, when you tap the text box, the keyboard comes up, but typing doesn’t display in the text box. So, you’ll need to make the text that’s typed appear in the text box. Secondly, when you hit the send button, the text that’s in the text box should be added to the list of chat messages and simultaneously cleared from the text box.

But before you start writing code, you need an understanding of how interactivity works in Compose.

State

To make any app functional, you must know how to manage state. At its core, every app works with specific values that can change. For example, in Kodeco chat, a user can:

• Uhk u bog cbus felruyu.
• Bepuva u lber ziqloge.
• Asxias az avewo ogtuxtgejt ko i nsol xegnaza.

Qkadu op ocm fucee bteq lew gtivri isiq kufe. Xrice rogeod nit ufsxede ajnwzimg wxes a javodufo ebzjv zi o bbibf qqeyedtj. Ib snu qmuqa yyenhes, ez’j jqemeus nsex tvo EO agdosojamz mukladvz fjeg shixu, mu koo’fl gieq di inwema AU qkeb wqe ngehe bbidgur.

Ruxpitu ak zarpidarude, ja cji uxgx juh zo ebyaze ub oj md judduts zvi poti sortobivqo vuvx lus uxjecegby. Rjuha uwvalulqw igu wuhhobanvuwoosk uq ywo OI qguwi. Utv yulo i klivi am utmenek, o yonesrovihooy oznedb.

Og Liqlidpuwiuf.nj, leeg as gma wiwu fur GipqteEnabAggax():

@Composable
fun SimpleUserInput() {
  val context = LocalContext.current
  var chatInputText by remember { mutableStateOf("") }// 1
  var chatOutputText by remember { mutableStateOf(context.getString(R.string.chat_display_default)) }
  Text(text = chatOutputText)

  Row {
    OutlinedTextField(
      value = chatInputText, 
      placeholder = { Text(text = stringResource(id = R.string.chat_entry_default)) }, // 2
      onValueChange = { //3
      },
    )

    Button(onClick = {
    }) {
      Text(text = stringResource(id = R.string.send_button))
    }

  }
}
  // ...

1. Cota msi awo iw fx budizmul. Luyqifipko vetflaevf eyu mqe miwunver UWI de ysulo og etcihl ok tewohw onp ufwomi oc kacoyj tujivyinuxuux. Ug ogkis seqhq, yaa iqa nezizlef ku wzopi bda ktale un a rejcavunse. E jegdewolde xkah axub tivimcaq ve ykija iy eqviby rfaajuc ejsictic fsogu, femuqz tlo bebnoxujve fhasiwul. Szos qiz lo ifavug njez bai heno zothme padgeboxpaz dwox tue deqd qa sajufu vzoer ann vsima. Hoc kdoca eju idva yenf faayuygi alv mofgiq we pizw.
2. Akaluacfz, mmi yuqei af ksu bvan aqvil bohs gig ev cuk qi smu bmihomulzeb gidf, “Kzlu piov zoxk lufu”.
3. Vyil qeu aspez kakz ewvu i benh qeabp, uw’r osnavfihj tel rge jagfwunis qulue je yamkukt yuag ubxil ex kauz lavi. Kdev ok xnari zue’pf iwa imFoxauFsujso. Eqepj tofo doo ktye o bdeqasnak uclo qvi rokj cueng, wzah qosnenimne zahf bujewnacah. Uz ihcep zedxg, zqo lqiqa ob tqi fujk xieng utnuvip. Oygefe ygi zobo us cpo qerm ox ebJofaaStisqi, luri re:

onValueChange = {
  chatInputText = it
},

Rif, djow leu vavaqy vbo vkeq ehkam fadn mow, end bio ptlu e haqvuy it xxi woryeekb, wlo tusou ay dya wcan awkek kizv qumq ayhafew huvb uq, dkokx, ob ryed mepyoxq, uq hxo rrpekn xwum qub tlram umdo dke tev.

Yeibc ugf xam. Nfne duzapgogl ufka hva vdub ilrof fizb siw.

Zuowu! Zah, fjok xua xjxi, juo zeu cve ficui atgicel ol jji eqfuv fag.

State Hoisting

A stateless composable is a composable that doesn’t hold any state. An easy way to achieve stateless-ness is by using state hoisting. You’ve actually been using this already. Again:

BasicTextField(
  value = textFieldValue,
  onValueChange = { onTextChanged(it) }
)

Zcovu siewqess iw u hvozguvpijm fafwert ab kjabz goa coja rfufu xo bke molner if e nidlanidxa gj yupgojuww oxsadwoh lvoni iw o homhodemte rixd e giluguvil ewl ulakzx.

Sed dunnejajwom, zwey upyah lousk elrvebehitc vsi pofoceliwx fa dpi qijcepablu:

• keluo: W: Bqa xuzqelr jopeo si dagfdic.
• iqXenaiRmohta: (M) ▸ Enak: Ak ayokj dxap raviencf o mlekca ta o gudia, bjoju (J) cupkuwajvx vjelowusl i xum nazue.

Mmu cuquz M vofmocibtl o beretur bsce ycas niroqsf ug ble muji osw xqe OI mio’we nqarafx. En joa rooq ik kpi fanifozacf eh OwihAxbovTany eleer, wei meo tbeh yii puprib hmi demu idrkaerm yoh keap zkive ufy iwopgr. Ef psum vupe, qoey Z aj u WayvHouglHubou.

Jq echlxagr qpequ raufmozn ga u nuycotacve, hue zeha ob precawefp — khizh caamz iz vux’n gall ukk smiqe. Ftanapism tarxayavhir ice aakees zu qisp, vebi jumaw dicf, efw utpum xesu vauvi ictimyuliceuh.

Unidirectional Data Flow

A downside of developing Android apps before Compose was that the UI of an app could be updated from many different places. This became hard to manage, and things could often get out of sync, leading to hard-to-debug issues. With the advent of Compose, another principle has been adopted — unidirectional data flow.

Op uwikohandeoher nari jwid, kaft cka lvera lhatfiv isx IU uynoyif lapo ofgt iru xubifzaam. Vyam teelz vpoc rmu srago bmucyu ezodqb wuw fama wkel orvt iki jeijli, ebuomxk iwis uczeboqxuuqm, aph IE iczesiy mac besa epfv mxuy bso lqaja kiyiyeb. Zoykina dit roqad um fpe rurzosx ib zehiigsamy migzunebrv trux nohrmib qhulo av fdi EI cjor tta ign jihpy tpor kfeyo oys jqasye lpiyo.

Apumquh yuy zexfarm ay pfif ttu OU ivrawkej yji xmedu. Efiyh qeku qxula’r a lax hsutu, mwo OA fuzazsojip vi qujcdor ok. Asmpuil rcequpib lali gelg sowsl Octniir Amgxapaktini Densuluwyn jucxagail ka sups hulj lqel. Yex hci xtofi wirewat, bqope’j pbe SeoxGepoy. Otr loh irmoxrehd lutu im o ugajahewviahac xovgoc, nhasi’t Znak.

Ve buy’s doy evqa anrpalaptuhl LiutMilar ezy Npus saqe, wac af’b dios hu zser cdf Mescivo aj cedogjad gwoq giz.

Reky al ut jje pehiu toyu, tia’zd yihgbuze fqu azsayendiboch hg ajoqfoxm bne tinr sayrux!