Debugging as a Skill - Speaker Deck

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Debugging as a Skill. D A A S @hi_man_shoe

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Debugging. - Need for debugging? - Understanding basic aspect for Debugging. - Leveraging Android Studio for our use case. - Debugging Compose Code. @hi_man_shoe

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What is debugging? @hi_man_shoe

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The process of isolating and removing defects in software code. “ “ @hi_man_shoe

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Debugging 101. fun testForPrintln() { val loggedInUser = getUser() println(loggedInUser) } @hi_man_shoe

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Debugging 101. fun testForPrintln() { val loggedInUser = getUser() println(loggedInUser) } fun testForPrintln() { val loggedInUser = getUser() println(loggedInUser) } @hi_man_shoe

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Debugging 101. fun testForPrintln() { val loggedInUser = getUser() println(loggedInUser) } fun testForPrintln() { val loggedInUser = getUser() println(loggedInUser) } Output @hi_man_shoe

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Debugging 102. fun testForLogger() { val loggedInUser = getUser() Log.d(TAG,loggedInUser.toString()) } @hi_man_shoe

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Debugging 102. fun testForLogger() { val loggedInUser = getUser() Log.d(TAG,loggedInUser.toString()) } fun testForLogger() { val loggedInUser = getUser() Log.d(TAG,loggedInUser.toString()) } Output

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Debugging 102. fun testForLogger() { val loggedInUser = getUser() Log.d(TAG,loggedInUser.toString()) } fun testForLogger() { val loggedInUser = getUser() Log.d(TAG,loggedInUser.toString()) }

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Debugging 102. fun testForLogger() { val loggedInUser = getUser() Log.d(TAG,loggedInUser.toString()) } fun testForLogger() { val loggedInUser = getUser() Log.d(TAG,loggedInUser.toString()) }

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Types. - Debug (Log.e) - Verbose (Log.v) - Info (Log.i) - Warn (Log.w) - Error (Log.e) - WTF! (Log.wtf) : What a Terrible Failure @hi_man_shoe

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Android Debugger : 201. - Debug the data loading/sequence in App - Can select the point to specifically check - Verify and move on! @hi_man_shoe

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Android Debugger : 201. @hi_man_shoe

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Android Debugger : 201. breakpoint @hi_man_shoe

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Android Debugger : 201.

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Android Debugger : 201. Re-run the app @hi_man_shoe

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Android Debugger : 201. Stop the debugging fl ow @hi_man_shoe

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Android Debugger : 201. Continue execution. @hi_man_shoe

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Android Debugger : 201. Step into next line from breakpoint @hi_man_shoe

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Android Debugger : 201. Step into the function @hi_man_shoe

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Android Debugger : 201. Step out of the function @hi_man_shoe

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Android Debugger : 201. Gives a list of all Breakpoints

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Android Debugger : 201. Mutes all the breakpoints

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Android Debugger : 201. @hi_man_shoe

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Android Debugger : 201. Running on Main threads @hi_man_shoe

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Android Debugger : 201.

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Android Debugger : 201. @hi_man_shoe

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Profiler : 202. - To improve performance issues on your app. - Helps us identify the issues. - Can help in CPU, memory, graphics, network, or the device battery. - Is natively available in Android Studio out of box! @hi_man_shoe

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Profiler : 202. View > Tool Window > Pro fi ler @hi_man_shoe

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Profiler : 202. The package @hi_man_shoe

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Profiler : 202. @hi_man_shoe

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Profiler : 202. CPU Usage of app in your device @hi_man_shoe

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Profiler : 202. Memory used by the app @hi_man_shoe

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Profiler : 202. @hi_man_shoe

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Profiler : 202. @hi_man_shoe

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Profiler : 202. Stats at any moment

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Profiler : 202. @hi_man_shoe

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Profiler : 202.

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Profiler : 202. @hi_man_shoe

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Going back to Memory Profiler @hi_man_shoe

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Profiler : 202. @hi_man_shoe

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Profiler : 202. @hi_man_shoe

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Profiler : 202. Java @hi_man_shoe

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Profiler : 202. Native @hi_man_shoe

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Profiler : 202. Graphics and so on! @hi_man_shoe

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Profiler : 202. Lets see Heap Dump? @hi_man_shoe

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Profiler : 202. Heap dump recording

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Profiler : 202. Classes in the code. @hi_man_shoe

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App Inspection : 301. View > Tool Window > App Inspection @hi_man_shoe

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App Inspection : 301. Lets you inspect Databases/Datastore @hi_man_shoe

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App Inspection : 301. Inspect API calls :D @hi_man_shoe

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App Inspection : 301. Inspect Workers! @hi_man_shoe

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Database Inspection : 401. src: https://developer.android.com @hi_man_shoe

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src: https://developer.android.com Write queries to test your DAO! Database Inspection : 401. @hi_man_shoe

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Network Inspection : 402. @hi_man_shoe

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Network Inspection : 402. Rules to manipulate response

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Background Tasks: 403. Inspect Workers! @hi_man_shoe

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UI Debugging : Compose. @hi_man_shoe

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Problem? @hi_man_shoe

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Problem? Rendering Performance Janks UI performance @hi_man_shoe

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I/Choreographer: Skipped 115 frames! The application may be doing too much work on its main thread. @hi_man_shoe

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UI Debugging : 501. - Help us build performant UI - Let us understanding places to improve/fix - Build global UI for 1000s of Phone and share best user experience. @hi_man_shoe

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Layout inspector Layout inspector: 502 @hi_man_shoe

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Layout inspector: 502 - Helps debug Layout - Gives count for Recomposition/Skips in Composable @hi_man_shoe

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Layout inspector: 502 @hi_man_shoe

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Layout inspector: 502 Recomposition count

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Layout inspector: 502 Recomposition Skip count

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Layout inspector: 502

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Profiling HWUI : 503. Settings > Developer Option > Monitoring > Pro fi le HWUI rendering. @hi_man_shoe

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Profiling HWUI : 503. - Each Screen has its own bar graph representing the UI changes. - vertical bar is a individual frame. - And height of it shows the time (ms) it took to render. @hi_man_shoe

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Profiling HWUI : 503. Consider it threshold (16.67 ms) @hi_man_shoe

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GPU Overdraw : 504. - The drawn pixels are not visible in the view displayed to the user - Can reduce performance. - More battery usage. - Bad user experience. @hi_man_shoe

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GPU Overdraw : 504. src: https://developer.android.com/topic/performance/rendering/inspect-gpu-rendering

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GPU Overdraw : 504. Settings > Developer Option > Hardware accelerated rendering > Debug GPU Overdraw. @hi_man_shoe

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Fixing GPU Overdraw : 504. - Reduce nested layouts - Use inline Composables like Rows and Columns - Optimizing backgrounds and backgroundColor - Less recompositions in Composable and persisting state values in scope of composable. @hi_man_shoe

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Strict Mode : 505. A developer too which detects things you might Be doing by accident and bring them to your attention so we can fi x. “ “ @hi_man_shoe

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Strict Mode : 505. override fun onCreate() { super.onCreate() if (BuildConfig.DEBUG) { StrictMode.setThreadPolicy( StrictMode.ThreadPolicy.Builder() .detectAll() .penaltyLog() .build() ) StrictMode.setVmPolicy( StrictMode.VmPolicy.Builder() .detectAll() .penaltyLog() .build() ) } } @hi_man_shoe

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Compose Compiler Report : 506. The compose compiler report generates report to determine which of you composable are skippable and which are not! @hi_man_shoe

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Compose Compiler Report : 506. subprojects { tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).con fi gureEach { kotlinOptions { if (project. fi ndProperty("composeCompilerReports") == "true") { freeCompilerArgs += [ "-P", "plugin:androidx.compose.compiler.plugins.kotlin:reportsDestination=" + project.buildDir.absolutePath + "/compose_compiler" ] } if (project. fi ndProperty("composeCompilerMetrics") == "true") { freeCompilerArgs += [ "-P", "plugin:androidx.compose.compiler.plugins.kotlin:metricsDestination=" + project.buildDir.absolutePath + "/compose_compiler" ] } } } }

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Compose Compiler Report : 506. ./gradlew assembleRelease -PcomposeCompilerReports=true @hi_man_shoe

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• module-class.txt : A report on the stability of classes in this • module-composables.txt : A report on how restartable and skippable the composables are. • module-composables.csv : A CSV Version of report. Compose Compiler Report : 506. @hi_man_shoe

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composables.txt restartable scheme("[androidx.compose.ui.UiComposable]") fun ServerList( stable index: Int unstable servers: List stable OnServerClick: Function1 stable modi fi er: Modi fi er? = @static Companion ) @hi_man_shoe

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Fix. @Immutable data class ServerCollection( val servers: List = emptyList(), ) @hi_man_shoe

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Or. @Immutable data class ComposeCollection(val data: List) @hi_man_shoe

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Pull Request Run the Compiler check Comment in PR Compose Compiler Report : 506. @hi_man_shoe

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Memory Leaks : 506. Cannot release the unused memory allocation from memory! “ “ @hi_man_shoe

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- Wrong Usage of Threads. - Context :D - Patterns like Singleton. - Deregistering callbacks? Memory Leaks : 506. @hi_man_shoe

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- Check for OutOfMemoryError :D - Start using LeakCanary (https://square.github.io/leakcanary/getting_started/) Memory Leaks : 506. @hi_man_shoe

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Thank you. @hi_man_shoe