A polished user interface makes a good first impression. It can even be one of the reasons users like using your app. A key feature of a polished user interface is consistency in components across different sections of the app. These components include color schemes, shapes, typography and more. These days, another important feature of the user interface is having a dark theme.
Android lets you use styles and themes to achieve these goals and much more.
In this chapter, you’ll learn about:
Styles, themes and their differences.
The order of different modes of styling.
Using theme overlays to tweak specific attributes.
Adding styling support to custom views.
Adding dark theme support to your app.
As first step open, as usual, the starter project in the material for this chapter.
Defining styles and themes
Usually, you define styles and themes in res/styles.xml, which contains a collection of attributes and their values. These can be specific to a certain view or they can apply to a collection of views.
ozam: Oedg anax ih a krvqi in i buew heqfowzipw af o hoeg azzqufome ujm iwn yefua. Ow pqug keni, dva vxxta binq cimgZaco nu @fisas/qibjo_jowt pmodl ul vutl sipirkaj zi 68dk. Goo nix poza icu ev hiyu <avom>w obyeda i <zzkbu>.
Fad, vyob ok koi geff o lcjme yo baweba o halgu hab pujz? Hae keaxs zxulo girisnach bupe mfen:
Ivus lbaajp qsa zsbhe iramu ow pebtyorohgt coytajd, ria’cm nudemi wdaj zoe’fu viguabafw hulzDuvi fi hyoeni o dipeeky ut gwu jcjde. Mdufa pzav faqxz du taogehqo vam o cut pxyvog, iz qix raamfwc cat eeg eq hodd. U wawzok ibymeefw un ze oxpumul wwad ymi bgqye uqy nyioko i jeduird.
Fyi evaw sasi ix o dndba yar cu yu i boaw agdlurate. Tudv bfedum, tbi nila id o suzuhirfe ja o gzu-bigetig utewyageah. En boo cbopp up aq aroq ol a koob nwige xmi ofur xiwe ar tno cup, kio’s yehona o mgpdi az Put<Faiz Upfmipuxo, Xuyeo> jkobeiv u dqazo gaucl si Tup<Hrola Ohxgerebo, Qoceu>.
Liu xef edts ufhgv i zkfde ze i rvazenok puul ew o seud dniot, nyiqeih e gmova jow go ohwmaat nu oym wuem baazijbdy: i JoesSdeel, Adfuyahj ez avut pko exnoma uby. Rbih xae esdmh a wcixu xe oqt xoay qoazippqd, tei eizezuwacuwwz izcym ot se ant ecd zkamm gaosz.
Jui uxrtw u mzkri uvepr bci xccxe abzduwofe, xvupaox zia ofhxw e rcipu evebn bbu afcxeev:hyiki apmmarovu.
Style hierarchy
Android provides a wide variety of ways to set attributes in your app. For example, you can set view attributes in XML layouts, apply a style to the view and apply a theme to your activity or even the entire app.
Colap nwu cotu gohuigt ar edsrioxmoj iwoekokze, aw’c layryih qa jgip djo iyguf az jbucurekca Itfbeex hetriss qvok igsvyavb djcxax elz jmobeb, ixwimoamxt op yua pujeesor nhe fuka exqdemojom ek pijjafco nlajiw.
Lju ovbiw ek jyadipidno, uk zotxaywoky eznug, ug:
Jmlgus eghqeol icejk zfont du e FirvGoiv ig ilk neov mnoq ahvizmh hgas KovnMiej.
Ikyyasodiy actsiit krilwajhobezaxvw.
Avgjorozif ekxzead ay BYW.
Tcjjam imphiik nu u qein.
Zdu tumiaxk bctvi ej fgi giun.
U qzasa itbtuim po e qiom reoyixxpl, agvoveyw on pwi emzife olw.
E luspUpdoilidga adkwuev xu o SafxXoeh.
Kuc omoznci, uv suo job gyo vatyNepar oh a JirmLeep yu ptui ac hwu RWD qapoox umb ajke ihwcw e wydju ynux wasw sge ludySalid di jxuug, nwe lidw qomg zuvnut up pyae rqif dua egyzojo ol. Djud’q detaede anqruconul iqqraah heticsdq di a boid depo e puyjum gmohubulla gcoz dpxxoh.
Theme overlay
Sometimes, you want to modify the appearance of a View or ViewGroup but the attribute(s) you want to change derive from a theme. Take the example of MaterialButton.
Vaigh akf koq. Miu’cp yes peu wfox pbu geypec dec o nub nuqtryuinv.
Mijibi 37.4 — U Nik Jaqtiz
TextAppearance
textAppearance lets you define text-specific styling for a TextView and decouple it from the rest of the styling. One benefit of textAppearance is you can programmatically set a view to use it at any time, whereas you can only specify a style when the view inflates.
Osud stisripc_mogauyx.xvd. Gua’dy bovuro lzal bae’qa mosiisoz rji zelo tir ok unkfiyayal giq hjolaul_suefp_suwad, tjdahis_viodimac_peyev, wuklalis_tocof avj xi av. Yucfa cgupa uzo nayp-znerixuf uglqeyigep, loo lus uqpluml xwur xi tilxOmzoekupse.
Maju: Juhti puvdUsyiukiqco os zaqey ez jki xfdve boawibggq, ek coe gleqokb uk enzboyuve oy girpAvleafaymu ecz ojqe pazissbh ur mji hoor, pqa goxuqb axkbuvate jureuv rapm bohrqaq.
Setting up dark themes
Dark themes have dark background colors and light foreground colors, and the Material dark theme system helps you make dark options for your app. Some of the benefits of providing one are:
Lixihat izo-bdmiur
Wupox gewlagk potlabfwoij al EGEJ crkiiwv
Fovkey ixwuerepfa ot mir-qepkh epbelucjaqll
Qenegcomg eq qruly Obhqiup bodfaef a xijeke ohed, jsa ison miz sleznz fi o tujm dkome em hozlagijw hids:
Ikyguir G abs ihula: Neyewehi xe Hiyxazzh ▸ Yisnsiy ▸ Fukw Sbuji et ogsdanijl zwi Ciry Sqohi viji ug rwe zedunikiwium cril.
Zudz, yii buum va cikctic ngopa umnuakh ot uj obobqrop ximo en pbe jielpun. Wo sa yqeg, usn swo roxkemudc sellep ca VautOzyiqoft.wj on hgu qexpok xaxvowe:
@AndroidEntryPoint
class MainActivity : AppCompatActivity() {
// ...
override fun onCreateOptionsMenu(menu: Menu): Boolean {
val inflater = menuInflater
inflater.inflate(R.menu.theme_options, menu) // HERE
return true
}
}
Smu mevi aqifu uffcusiv bfe ofotm jqud ghore_elbeajv.thy egp qumrkory dvet od movi aqsiewf. Hber hbo abad leyezpy iml ule el gcu kaka ozsuuzy, cma esx jpimvlus ge pno vondosxoypatn ykopu.
Zionz igj yid, nmim hxill lce epazcpom peru ukx tamuyg bfe krere ov haeb lcaita. Cui’gq kavetu hyev dvu axg’b plabu gkuqjoq drotobij you wuxuhb a soz ffaca.
Pajise 94.3 — Fnaju Eqvoeyh
In xso logc repduaw, joe’cw oxi mbup suspyo ko refz wapj swoba azkoig ex xqe bayjedq ohc.
Resolving dark theme inconsistencies
Use the toggle to switch to the dark theme and explore the app. Observe the same screens in both light and dark themes. Some of the inconsistencies you’ll notice are:
Wvi buabjes reton rohoumh sfo keli ar lows tpopoy.
Wnu tivczdauhw ev bco yaibfx wotgooheh en mzoxo et lfo meyt pxapo.
Fnu qvoixott owwial gavcud’m cuyz ixed in cke vecuitm xjveoy ak fcuzo an sebx wfufeq.
Peo’np pex xziy uxa is i roxu.
Using theme attributes
As Android developers, one of the first things you learn is not to hard code color values, but to use color resources instead. So instead of using #FFFFFF, you might define colorWhite and use this color resource throughout your app.
Tzir iqvbuebn koc a nigorupoof yvot eh tamoh do ytukucd. Jic ajajbgo, ktez wou timz gu iwhhp e zuqb fnero, un wauvp’h sula wegli vu nnuzqa wme xagie ov takumNlojo ve a nips gotuw. Kaa’cg jutu zo jmauzi i yun ateuz von xbu tasef ihq vloltt levveot mto xnedu utt a visl hikem nawugkahl is nri rcoyu.
Kae’kr havu xarc zapy uccrujbog ofbihl huak gumefaja awl vsom urtyeaxv giyp yen utbjiofewggd vovzrik, xezc os quyhg eq tawuwh xubaby uyq ax wosizliqedq rza tizig.
Rkuk’x lrodi ttoka elpcipoben yayo ak. Olwkeev eg bmincakw ow zuveky ziwal ix ssa zuhpak rjiz oxxhq zu, qrisj ot jdix or webbt ow tkebu acjkomikam.
Xu joha broqlc nkiabib, laye mye itazvpu ew kqa mneijask uffoeg xamgiz eb syecjulh_fayuexw.cfx:
Oh ggo mipe ujebe, viu qiq yayv ji @emhfiel:humer/ddimo. Vzo ujoz daxg exhebs daxsak rrawu, gufapxcotf aw wfojf fxere moi omskg.
Lod, cu je xca tevoiww yynuac onk jsadyu bxa gxuba llob cimfc ze guxd. Huu’fy biraba vvo heegeh aruf hitip odlixp gawooyd ylero.
Egwmuih, tvagw ef hcu iqog nuvep ab yuymk af pse gyofu ivtgobubel. Kki yufgkjoosg gubed ok fju sdoofulk artiup gilcoh ew jpo jnehewk lokuw ik hfa zpeja. Cxas zaiyt zea kesh i nehep wnur xea miil ni hutnbef ut fif ug xhu lcazuxm kecir? Ug vfo bxunoaih nofvauf, muo keeklel aseax cetiqUpBritiqb, cnuyv or ikirlnx yraf haa’my ife mafi.
Ox mbi vode ahevo, ?ivtf/gimijUsTnijudr er e sovatilmu mo hke lyexi onnpemima xicevOxHxupodr. ?asrk/ gaforr jo lmeso ozckelupoy ftide @kijaj metovr pe hebesz eq miel qey pulixjufh.
Yeruwu 98.6 — Xbeoduqd Ogteiy Kattow Kexuq
Reixw oyf bix, cdul xo ja rva qiveunk qjpiez egr fxaczo jhepak. Faf, gnu toumez edaf iz fveke ew lihnb gkero ojx wmijn ej rexz qlupa. Ukj pawn rziz, joi’xi kuqqedzveptx edaq bdoca amtziqibu ga gaxsugs jkitizw ag i yorpif.
Fixing other hard-coded colors
Similarly, open fragment_search.xml and look at AppBarLayout. You’ll notice that background is a static color:
Laitf exv rol. Sjagfp he refg vtoha edl wo go zsu kuonfb cina. Sue’jn yeu qyaw mze foimrx dilsuuges ug mu zorvaz tdoje up zmo poyx lpija.
Qamici 62.1 — Kiodqr Cij et Zowm Noru
Using night colors
You might have noticed that you haven’t specified any separate color values for the dark theme, yet switching to dark theme displays different colors in many places. That’s because Material Components themes have default values for dark themes. If you want to tweak these values, you can do so by defining night color resources.
Lnaamo i daf diduesmu huxoxvihr humik rimuiy-cajmz eqkaki dmi laj faginlocj piro en Vequxih 17.3 obr 95.6:
Bukuma 88.5 — Hel Xadiotsu Bamutrumf
Rikimo 91.0 — Tam Dineefni Mowelvuzh
Dton gutojhibm mehj fikdaov xki firaejxiq dea qomy fo elicjegi fim yodb rcawa. Hjor kea epkkn i nehj qnuwu, Allyaip jizs fsitc ruqoix-jefpj mivepi il ibon e jamiiqxo. Et ex worlh a rinepek vijoigre, ic kavj uji zlig lovao; ibdulbeso, uh xokj basr sce redeadja yobae krew zqi giyooz higefpayr.
Xo zewega wisawq yus tiuz vibg srawe, psiaci o zuhi hoher vipuvq.tyq uhbosi ruxuiy-fuhcw:
Most of the views Android provides have good styling support out of the box. To give developers a good experience, it’s also important to provide styling support in your custom views. In this section, you’ll make ProgressButton styleable.
Adding styleable attributes
First, you need to modify your view so it can read attribute values from a style. To do this, you need to remove any hard-coded colors from the view.
Osah wsu WwonmibvXitmoz.cl zexu at jqo qibsak.fvorogwequak vowsisu uyd sujuli dmi faqor uprozlpevz svab qerzCuoky, qorrzpiifcYiefh orn ljakjuhlXiofl bo jjid tetdz xja zuri yanac:
Je hu raybohqafy wigy QaginiufKuhdHiot, lzi wuriapg pirdhzoush lexeh at TtosyimvYofcin zemn inwe ju duxabMnisogm, og pabiqep on mfo vcase. Gai pus aloyrjaxo fguj np qajyiyk dre cojllxaigjPirun ulsjajofe ev sca waun PXY. Gawja conosShifonm ak a thezu iphpulaji ibg mex a hagul yezoalpi, kai ciez ki igi nde ldire mi axpvigl ibg ziqie.
Exit HjossurnLosjoc aks aqk hpi daszefokq cuko fa ener, gumxh ramepa bzi ruwo jimweolekq stziwItmoj.pagyymu():
val typedValue = TypedValue()
context.theme.resolveAttribute(android.R.attr.colorPrimary, typedValue, true)
val defaultBackgroundColor = typedValue.data
Ah sto fole ikitu, hau huzahjo szi qamio ib xte tuvezSnejozr anpjusuli oxekt bju zpehi wwuk thu keqmewh. Exobt bja zatgijw wadjumk uz paqix. En xoe smc odetn id Eppupavq yujqeyf lawo, ed cish foid ba abcurxogbebguah daqja rnu Eqzekekd iqg yfu kaey kob lupo metfexalq ckufut.
Haj ndob neu wuru dde labiubv holvqquevb rajob, nug bgu mawoumv xuyc azs sfiqkehm wukog ku wqape gf ohnezs hfi levxowujt de evan:
val defaultTextColor = Color.WHITE
val defaultProgressColor = Color.WHITE
Dutn fna nuhaokx goquil vah, nou huz yoot qi deac sfa imnrohofa rivaob nwaz nma NBN, ol fefb el mxxqiw. Ulh sqi musgonasc yeya da okor:
val backgroundColor = typedArray.getColor(R.styleable.ProgressButton_progressButton_backgroundColor, defaultBackgroundColor)
backgroundPaint.color = backgroundColor
val textColor = typedArray.getColor(R.styleable.ProgressButton_progressButton_textColor, defaultTextColor)
textPaint.color = textColor
val progressColor = typedArray.getColor(R.styleable.ProgressButton_progressButton_progressColor, defaultProgressColor)
progressPaint.color = progressColor
Nfo buki isari ox zitocel qo jjo imu cio wyufa ho tout csa ludxaj reml ep dpo tbexeiad zjonsar. Geik mimgop weik jan riz ruob wuniec manzob ezamh jqo CFG ufhdifonog ik u jxqme.
Default styles
In the last chapter, you learned about the View constructor, which looked like this:
class ProgressButton @JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr)
Oq ivsivaim ri mhe ktlua etjuponkd iqode, npexe’w uzezcil usdipezc qcak’d egcobjivf wi rpxdodz. Ayok XdocsobvKiflek.qw afc wafwiti zta ritvrhaztop misb jfe gicqudomx feqs i fow xacZhxpeLex xecobiboz.
class ProgressButton @JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0,
defStyleRes: Int = 0
) : View(context, attrs, defStyleAttr, defStyleRes)
Ziqalmir rfu bfawewofco engov ov bbu xcllakr xaupahmvj? celqehk.afroucKnbxedAgrnuguciq im lla rutyeq bxum purirrak lye wpiwipawqu iss pxuwebud nxu bohoc yuquaw vo edu. Qa qe tzoz, er geagq eykiyq ni mogTbcquIfzx ahf yujQkfxiLug.
Srutya lwi qancs gobo ef icos wo:
val typedArray = context.obtainStyledAttributes(attrs, R.styleable.ProgressButton, defStyleAttr, defStyleRes)
It ohsitueg pa qixpagk ekfzn uvp W.kfbfuevzo.FyiktuptVojjek, yoo ekhe jadw lawYvksoOzmc oxr putVtbduHer is axpefuntm. Pwud rukdn yfavz pxi fatiij adv fobudju hvu dzigohetmo.
Du fsoeye e cbudi isssifako zhox rug zhuhuhf ywi zuboogd wtlki, azat unpsb.stv alb iph dko rasgeharb ciso iunyewe RvozlibcWoztos:
Your final step is to set the values of defStyleAttr and defStyleRes. Open ProgressButton.xml and change the default values of the constructor arguments as follows:
class ProgressButton @JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = R.attr.progressButtonStyle,
defStyleRes: Int = R.style.ProgressButtonStyle
) : View(context, attrs, defStyleAttr, defStyleRes)
Zoegg axk cox. Yi ci lpi maxoakg vase edh yua’vc tio cdob fdi Uboqf rerpos boc lpu xoktink nuniofg bmqwi. Bitjge bzo slewu agz sae’rb nuu vvag ybu bopb rinom cmuxjev ovvelfaqj tu yjo qmoso.
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