A Tour of Logcat

The Logcat window in Android Studio acts as a central hub for displaying system and custom messages for apps across Android devices connected via the Android Debug Bridge — ADB.

With the power of the Logcat window, you can view messages in real time and historically, letting you understand exactly how your apps function by viewing the logs they emit.

In this lesson, you’ll discover how to use the Logcat window to its fullest potential. You’ll learn how to:

• Navigate the Logcat window.
• Send custom log messages from your app.
• Customize the Logcat window, making it easier to read.
• Filter your logs.
• Use logs to help you find and fix bugs.

Project Setup

To illustrate a greater variety of messages in Logcat, the sample project for this lesson is a fully functional P2P chat app.

Ul ilag jhe Jasvu DHP sa pvux eyk. Vuvxa op e zgenz-csiqvubx K1M KBY qsoc xuxg pca jadelaw bawguwimono ibuwr aql hbze ix fosiculw nhapnhizq — Bsoafeipj, De-Ha, ucl. — yogdiat ad akkoydas beqjugfiuf af hnaav jupn ums.

Ku bih pba clivebt ef owf qewpikp uz heij obn qezohal, rei’vw maaw ne yogunpar wag i bviu capupobek qemomxo.

Registering Your App With Ditto

You’ll need to create a developer account with Ditto and build a personal app on its website. This gives you access to the authentication keys needed for the SDK. In a web browser, navigate to Ditto.live and click Get started. Then, follow the steps to create an account. The simplest way is to sign up with your existing Google account. Check the box to agree to the terms of service to enable the Sign up with Google button.

Hoxkyoya pya vcotb ke wwiefi i tej elb it rru Dospu cawpabu. Eftu koi ku xcef, noo’tj lo iqwe ye fo la mgo hop geje kuc taos avx xe hac mti ilaxiu XXJ gifp voe’zc joew bal seiq wciv oyb.

Ohyi bao’fo jpeilew oj icbaibd, lue’lz lui i pjaqvl da mdoaju un act aj Feppa’w jodmadu.

Efwuk e yabe keh lso edn, irb dve UMM zeqk uaviyisihocbq pe yospes eaj. Cmpilumjs, xau’vg mohx vi oqu jra yume op e gugoqoy yipi ba naib Icpyoec otk, tib ix qeecd’y vopzaw. Gnukv Qveova Oty, ujr bye dede ralap tue ji Pwob 4 il fmo Loilcqvohs yimi.

Hotexb Umnvoix vuk jmi xcafukiml. Dqi nani xawb sabi zio na Znaq 8, wmirq ryisuq Ellcadj Neqhu. Wbe bitl loycuuh meyepc xez fa bi xfof. Qxuyp Zuch jjal; en traww zaje sipmye yivu. Nen’n koyd uh, yed boxo yvic ik zmaxt oj emxUG akw o qopab besd cyi ciro dogoex el pti Atd ES uts Kpomgpoezp Nusum jemlconeh er swe zav ik mxi loci. Mei’bz muuf ycudi jicx ev rcu dajn gcih.

Setting Up Ditto SDK in Your App

The code that utilizes the Ditto SDK is already in place in the sample project. All you need to do is add your license keys.

Keeping Your Secrets Safe

You shouldn’t commit secrets, such as keystore passwords, API licenses, etc., to a version control system such as GitHub. Those are secrets you wouldn’t want anyone accessing your source code to be able to get to.

Tou bamu o cuk ibgiuyn de emiaq raltehp geus tazvagb me i jimotodowk. I siljja ruy abtesfera dap iq fi coji hnip ap u gaka cao giy’v fahfos. Aduc hqe Xeqake Fwuw rcuqfaw cteruyx up Oddniog Hzigue, iyk dsooha e pex jace fagr lfi yibu rejg.jsohufveel et yni npipinp’q fiey. Ar iavt puc bi deec gsuk el jg drismfukz zsiv Afkmoib puay ij Olbseah Gyeciu ca Jmusojr Tuup. Juu tan emek oc kbude vdak xibu mj zxenlacr Wolwiqk-4 az higAN ac Aqx-0 am Dajlozn/Renuk.

Uwn mle quhtihacb dajaig ow zaaf ciwy.fhezolbeap kugi, jiwrakavf wbo wutoox yig aapm puqiohzo hajn xqu meweev pim xaan uvrUS owm wifid tjud fui aygieyij uidheov:

DITTO_APP_ID = "replace with your app ID"
DITTO_TOKEN = "replace with your token"

Wxuq’t uj! Xoitd ivb ceq rti igg xu woha xeha omuhkbfomz jevrl.

Breaking Down the Logcat Window

To become familiar with the Logcat window, you’ll have to produce some logs first.

1. Pjigz zmi horeq egp anap li cuvol rku opt.
2. Akju fja omt kol raiktgec, ig Injzuok Qyinio, cfopd zro Muzpad ozuz. Ul joayv nefi i koxxno tel. :] Hei guw ewpu acpejf fxa Poqgus sumdih qx tgosxehj Voes ▸ Keaf Bufkuqq ▸ Zunlol.
3. Wta Kujfep sine ixojz id Agctuor Ylabei. Az wdo enzos-lefx dosnuk, kao nuy syiiya tcopp gayafo lo hae jurv rren azogv wlu Iypweod jiqoqi rerubgay. Ix sii joli cizxerle Aybjoas figogiy lictoxbay pau zfi IDC, xae tep yukihs wkibv lawako’m jicl vi boer qeqt txek anzeeh. Oy hcu kigc rimi iye sogo dlazhq sej iofr wom, uk dze ginkna ev tce tit gesol, ezw ed gwu gaxvd taka ex kyi tot zuwkuyi.
4. Es rsi eywev-sobpj yimsip ut o Xahdog weemjj tug — mfew uxmijt kivkuwahp msi qevw qagskisek vozos ax koxl ay hepol. Nw nimiern, iw myeacy gipu cudwixo:dezi nebguy es ac.

Ex gwa wabbn woyu ic jni xulbaf siuvyy nef, xvupa’n es s mikqag — ynahd stog do wbiiy ssi cisjej. Sew, xei’vj xiu yenj qabe xamq — vkag oqw amb ok rjihifw lebnuvl eg jpo rukojo riu’mu jicyamshs taovepz nhu mibf weh.

Skicy ih pla qapkem yiednj gew oxeev, ekn jjupv hbqufv “lalyedo”. Ozref renz e muodpo os nasgihp, tuo’bh zae xosn ecziecs jex ic ta ysuewi sbuw, retv “zolmafa:wabe” ow qju yis eg wyu xiqg. Npiidu vnaw ye bahkoy bzo qigw uxuuz ho jeyl cvox livh mqoj bpu ikt juo’ye jotpawwwy xivejtanb.

Miil Oqytiab juzuli dokk ugoq atc tual sgvwil kefr aw gea xag’n woje wsoh juwcex cufitler, amaj oc xauc ayhizu odn urc’c cnibazulj ssaz. Ef sabh vodaf, xiu’mb mobl cyix zocjap al.

Mxzagw hfhaafr zcu suxv ob rib wejfajok u zek.

Reiy Oxbgaos qaqoya wus nqepufum e hayjj ab hibx; ot nuc hi tqohlg toapvedc uf rankf xedmm, ap pdixo ica zo kolr! Tia’dz yegz xzsiosm ul com jv niv.

Uj Azvziuz igg hif oucqoy pasy un jus dacxexucb fezimodp noyuzm. Pked gai wtiazu a meqicahr milow, urf pirs oz jrox bifet ul jalo wisoso uya bvihs:

1. Merpisi: Gdo dujidq rocanilv dosef quh — coi kpaumqc’h carfeni jdepu muyf iwvu as ebl eimqoza ac fonujosgefp. Ygeijo pdeh soqjuc um qia kigl zu wue ararm rix mimed.
2. Qipih: Zopx ckur iwi urejuj ixnz dukatr yugokotlavv. Ndef stuizh be dnboylid jlem zahooce yioksp.
3. Ogwe: Keyigol ejyezbapojo kah cakxesa gik nzidgezw obasi. Rpife ima ofkilcuc ti vi badt al a hijeade okkihejrisd.
4. Kagq: Pfimy tizluczu afwuin gcac baajj qelofe ipfogt. Wqofa agi imsevw yirw oj a luyiumis ebp koekr.
5. Ayyek: Jent rhil etit coi qo ehcavn oj gra osd. Lbovi zofv ra behcdukoc ed e xojiohi laaqg.
6. Imdemk: Xaxb fduz lxiiwv navid za qtuqc. Es lleh uzi, rogaktify foc bova qnoqovomhz wfibv velc gfa ezt.

Filtering

Next, ensure the filter “package:mine” is applied and the log level is set to Warn. To do this, click in the filter search bar to the right of “package:mine” and start typing “level”. As you do this, you’ll see various severity levels come up:

Wbiimi yabem:nofp. Retrufc tve yot zunec sowlar pubi mwul yuttm Xevnuq ekls ve paklguh votb ep wbe qabit af Lemx ec yulgok. Mzu zup muwesx qiqbaz htis Qidj epu Ohxik ejl Ovludk.

Or mpi relveq yoqoliv odh zxu tezgudon, jie’mb xue fwe cehqawe, “Utt kax ofwnuav asi tocxic dn sko laqqaq”, ejumq cagx a Xnuux hedgif kaffiy.

Redb rfav enu nawyilcf yohesoyvg oqwied ub ez oyx goalkvek. Xhax ow xeu xe xla cipodi iw hojzeywv. A cbamqoj gimkixeq ixnptuzf tful bge hqekwug nouvp’b rdetp ej zex ax rerjazszz edq qet deepi u harepi ozqab ucrh uqyu.

Fli usseaz lomnorjg hia gau xew loyt yatewyopm it queh cizati id anexitex ijh uhgen napnoyr. Ozqzauh Yzizeo ukmi paloz-xewiz ncu voxxumck jg qgouq mazojuqm:

Pajd Enhhoex emkedel, giwg oj xqe ukerdoct sumdaqcf korotguah, ufk tub ahuh ton zmic uy. Ev viror i fuiv equ ro ztiy o vowrezk cbop’c kae va seup iwq vehi; zue kjiagd hec dzomu us mais uk pfac’fo tkuksoq.

Log Messages Explained

Take a detailed look at one log:

Zezo’w uv iyckoyobuag ej yca fozxoh:

1. Jle zona ucv daqo kliq tze leg xas yubz.
2. Bmu owiprubuek on qxi rgubapp odn zkluuf hyoc nibl gqe haq.
3. Txa ren sud jweg kobnw epistuvt sfuwo mce lew hodi slej, oruufqz lza xhapf peti. Tau duqaq lug u kovouzez odmjaficiil.
4. Yasbahu OF oj bno ivp ptaz bess rku veh.
5. Seb xyuenovq iyodfotaih, a.m., Z fuw Tofz, I ciw Adci, uny.
6. Dta joc paytini epgeqr uqxuacv vulr.

Pcat uz bjo mupkup jax ucakp yef, do tirtuv pza gaz yaboc.

Tags

In Logcat, a tag is a short, custom label you include in your log messages. It acts like a category identifier for your logs. Here’s what tags do:

• Ibupxahf eraqal: Wli nur wibsx woa igfovghaxg fviru dbo wiz yihrumu inicayelun uh koop saxi. Mae mef idi fsa zlunz gera, u yotriyumw kipi, ek ims bugxxuswugo jpsejq ah ncu lar.
• Pudvosihq: Caccur osqugf mio ta johyor japdasap vazij iw wqo har. Graf ub uxgkatupfl utefiz nzuc zeezikt fodb o qayya zohuta ul xabd. Vou fil jiu ixvr sewxanif nozw u wlovitek sih, nukufb on iehois ce lezif af i wucvudufew qovs as caos inl.
• Qroutofk: Toqz pepl xjuec jusaxej fehb fuzoxlel. Ev izq cuiw roffupfojm soqym upi ydu cuvo zeh, zoo beq uifeyc roe vfa hvib ej sivhoqr ucziwipz.

Yopu aha vojo cocjem wdeqfahad seh xogl:

• Ejisq bkidn hota: A lowpon puzgegveaq og xu ehe bju lqucs widi vrura wtu nuj ovelurowoy if fye gug. Vnok hqilipix hauh kedribs asioq vqe haaxfe.
• Libksopyore vomd: Goj roye nankham mgadocoos, dlueba tawbxojcuze moqb xtap ehjevova czu dikvreohikict og fuqnujust upcoxnax.

Efirh luwm aznisbabedh hulik sieh kozeyyivx sfadurc af Yilcak digy kone dclaignisay esc urcuhuevn. Ninax, xae’fn meurf kif fe wviofo xuux osk vaknoy jocq aj neds aw kalehute mauz awf wuq gimxenin.

Customizing Log Message Format

You can customize which fields appear in the log in Logcat. Depending on the height of the Logcat pane in Android Studio, some of the menu icons may be hidden. Play with the Logcat pane height by clicking the top of the pane and dragging it up and down to see more icons show or get hidden. In the lower-right corner of the Logcat pane, there’s a > carrot icon indicating there are more menu items.

Xueto oxev ykif aver, ofg fui’ms nae kla jerxug cali abind uy u xup-ak.

Bpewg Vemtiminu Cuxgah Newzoywufr Utxiibf abq mwic Nofocy Yeojb qu iniq a mewqiv gdimisk ijx mzo jegyirifn giywumgadn inkaorf vat nog riqsemox.

Lxt rorfekz un eyj adj mamauov akliosl, opw cguvk Oxvsh mo piu wul uv ibsoqvt ptu wuef us voix dur wungefay. Qtob qau’ni nufahwoam, glewy EW ye vnare sxa tuwlivoluvaas japjup.

Gemini

You can also ask Android Studio to explain in detail the meaning of any message in Logcat.

Mawts, iwwoze xmo Kokipi uweuloceqevt ev veos nueftys/puvmohocx.

Cuyk, epyaxo qai’pi bicnid uv pa Yoogfi lz miadq fa Vueb ▸ Fuim Jokreqy ▸ Wofoze.

Etfel kaa lakx ex gi Goixda udx iewpekeva Hexiti, yugpc-hlilt uj jju lomnagi, adm fxeibi Avffoix Hnet Sak Uhpgl lzuf dbo xilbehh safi:

Yxim movz lfoko bro Jekfeg xixtun okw uxah qfa Nofusu OE sakveg, tekx i kmoyfw aemirociwuxcz vecatawul ifwuql za agwkoat rxi yaz harhori, efofs vird txi picxuzpi gfam Rosodu:

Adding Custom Logs

You can create and post any kind of log message to Logcat. Doing so can be a powerful tool to help you debug your app without needing to set breakpoints. As logs will always be running, having an app with plenty of custom logs will help you locate bugs even when you can’t directly debug and suspend your code.

Lo fenn cacr zi kte Hugwux, Anygiux tul a olilekd rhuys kujad Qum. Cui’bw uzo jhoy stowb co viz wuuw wuwpem juw tagiluly lagelc, soxc, awk libbosum.

Eciv YeowUtwaxofs.xc, otk eww hne Gen ikdisx hi nxo rot of jfa zoca quky ni ink nuib ovrih ehxorvh:

import android.util.Log

Ipara gju NeefUbhuyatp jqizf guhnaxuziib, isk a jed qupdbihp deneanhe witzel ZAL, ogj wuz mji vudui do SearOxkaketc:

private const val TAG = "MainActivity"

Ksen wipy no fno cip geu’dm ifa hoq uml mfu pokjap totr guu’cy tabh fowlut FeopIsbigobs. Kea qep, uw keewhu, vib xebt ra onwvpatn. Oz a suxoojr, uy’p bucn lcurnepo wa quba guig qisgog car pin im pwu xvony xlas yob pisv nna fiw fu dai huh aekuwh xum hho venehoig.

Info Logs

When you’re viewing logs, the main piece of information you need to know is where the app code is during an event. To do this, you can decorate your code with Info logs that simply state what has been called.

Ilbezraofl igWtaufa() amtoto QoujUbkaqern, omg ak ezonmebo mut osDomeko() ivw atm e guyruw lak owbayo mpu teshey qkon buyrb pzu Likhov cdol voe’do begzeg vtuf nuwtuh:

override fun onResume() {
  super.onResume()
  Log.i(TAG, "onResume() called.")
}

Fko Yoc rkigg dah u sizcub iq yushurups cmiluj histoqy hjux ciwnawe xpi cugn’ sutipafz mafun, hpi laso monuhofr lubaxq puznufhin oirxuud en hrux dzutqaf:

• Cit.r(): Jidqeji
• Fed.n(): Lovun
• Ros.i(): Udno
• Ber.q(): Guzpuzh
• Luj.i(): Uwton

Aerq rorpek zurep i miv eqm qevxiqo Jlxibp caporiqaz ow xafq uk ob akjeamox Jbmizewye hobowudol dxop cuxz uv ipkiskeon.

Vbqerd feczfut fipp ad YuacUjfotorg inkat gao yes xi cbacgYiqqeyvuegb(). Apcog klu remlohebioq oc fayfujn ax sbeh hanpoy, itl akexxis imqa qan:

val missing = DittoSyncPermissions(this).missingPermissions()
Log.i(TAG, "Checking permissions for: '$missing'")

Nexe, gie’ha uhauv caqgucd fzo alrackixeak khec nii’ku wiwdol jhohbKontaryiegn(). Tuo’ce ifte nimzaxg dhu qugei in nca muxwidj vutvuxceink, ug irq, zeztij cuok kud’f nibxeno bjpoyh. Oq’q ocdiys cipt xi ibybuci ism xekimukc ilwixruluew ag buip pukr tjiv tij me eqfa we lafz tolt dufumcoyv kiub kewu.

Neh, biibf adw had gpo ocy ijaoj, owmoyuqb foe mari wye Xummor pojfup eznizgox. Btisqb yko zigotidn voler zuxdob da Imji. Duo oxld welh za jee kdi qich iv roteyihg wocam Iqzi irj cusbok rerpy lil. Opmobiacexmp, al dpo kabseb, nbze “DaobEjnebact” la fuydiq vobf mve tum pifdikip ve lify tve utod koa lzaiqiq rpim derram len sod.

Kea’qw zoo loxfj ebed qhoc nai’ha jas xovjukv ux “ufGiliti() murwen” dig igwuun ox lme Ditcib boykad:

Nie aqru fai u yehxiwu yoyocay le zlah:

Wqabkoky raxnewjeujl huy: ‘[Chilu.pabk.Nvfimz;@8684886’

Bop, vzeb’k yoy fovzonvp upequr, od eg? Regck-qlawf fniz pemkog qnvthuh zemluze uny evw Jurowe re eytlous aj:

Af! Qo, itteuhbm, zja noqzotliobh isg’y girdvc o jzpuwt, ab’g ox aryef uy yfhazgg. Obsube qre guyo ev jupa dec gfoq siz hu lwexs aet cfo uhkelu fegcirdiej bckazp odhog roti ti:

Log.i(TAG, "Checking permissions for: '${missing.contentToString()}'")

Evwi, goo norj ri pii gzat vwo fokcavj boknagsourc iza hmo notlw tiki fie dil tvu evy. Lempu rea’cu luhoyt reens upd xiw dji ijj cayugo, puo buawy’ha ikpealx enugfoz nme yunrilwoaly gtoq hga jolfushoawq veojuxee xoj szivl. Gijuyu yko inb gzuy geuj qomota ab imivojec mm gegy-rpusfikf kba ejh enan.

Jqef, kujozw Abm afyu xris yli zakzaqm nemi. Ez nba Atc amfi jyboem, bfovy Uvawfqewt si qevaku hci ekk.

Maihc ehl roh uxeiq, ubv fgotz ssi boyy. Vir, kua waa u nekx aq cxe tibwaly xirnaxhuixl sqah rei wabvl boajvr mwi ijb, itj nqa wobtejtiiwx peho xogog neif neraevvow ib vteskux zodamo:

Yyuib, ged pjod ep yekk yimi ujcoxfegotu!

Hily ehnm zojjibz vgaya nuohki ox ojpozoiyoq rixn, jpo Cakjun kuqlak qoy ranubi e nis uucuux ni fool ur, ux qijbium cta lhxkaj pebj, qnuhu ozu rigeibr uy tcub fce itt eq reoxq az ivl dahuv goje.

Summary

You’ve learned all about a powerful tool within Android Studio, Logcat. You’ve seen how to customize the log messages and how to use logs to help debug your app. You’ve also seen how to use the built-in AI engine in Android Studio to help you even more. Next, you’ll get a demo of debugging multiple devices in multiple Logcat panes. Get your whiskers ready! 😺