Jetpack Compose Mechanisms Course (original) (raw)

• Introduction
• Preface
• Who This Course Is For
• What This Course Covers
• How to Use This Course
• Course Structure
• Practical Questions
• Quizzes and Exercises
• Earning Your Certificate
• Staying Current
• Issue Report
• How to Study Compose Mechanisms
• Build the Mental Model in Layers
• Read Code Actively, Not Passively
• Go to the Source When You Want More
• Use the Assessments as Diagnostics
• Pace Yourself by Depth, Not Page Count
• [Chapter 1] Compiler Fundamentals
• Chapter Overview
• @Composable: From Annotation to Code Transformation
• The Code You Write Is Not the Code That Runs
• From Annotation to Type
• The Practical Consequences of Type Level Composability
• suspend vs @Composable: Two Sides of the Same Coin
• How @Composable Changes the Type System
• The @Composable Annotation Declaration
• The Constraints the Compiler Enforces
• Composable Call Checking: The Type System Enforcement
• Composable Type Inference: How Lambdas Become Composable
• K2’s Approach: Composable as a First Class Type Kind
• Summary
• Practical Questions
• Stability Inference: How the Compiler Classifies Parameters
• Why Stability Exists
• The Stability Sealed Class
• Tracing Stability Analysis Through a Concrete Example
• What Makes a Type Stable
• ClassStabilityTransformer: Encoding Stability in Metadata
• How Stability Feeds into Skip Decisions
• Strong Skipping Mode
• In Practice: Fixing Common Stability Issues
• 💡 Pro Tips for Mastery: What are you really promising when you annotate a class with @Immutable?
• Summary
• Practical Questions
• Lambda Memoization: Preventing Unnecessary Recomposition
• The Problem: New Objects on Every Recomposition
• Composable Lambda Wrapping
• Composable Lambda with Captures
• Non Composable Lambda Memoization
• IntrinsicRemember Optimization
• Why IntrinsicRemember Matters at Scale
• Summary
• Practical Questions
• Feature Flags and Compiler Optimizations
• StrongSkipping (Opt In Since Compose Compiler 1.5.4, Default Since Kotlin 2.0.20)
• IntrinsicRemember (Default: true)
• OptimizeNonSkippingGroups (Default: true)
• PausableComposition (Default: true)
• The Interplay Between Flags
• In Practice: Choosing the Right Compiler Flags
• Summary
• Practical Questions
• Reading Compose Compiler Reports
• Enabling Compiler Reports
• The Module Summary: module.json
• The Composables Report: composables.txt
• The Classes Report: classes.txt
• Interpreting the Scheme Annotation
• What to Look For: Common Red Flags
• Using Reports in CI
• 💡 Pro Tips for Mastery: Why “skippable: false” on an image composable is usually a false alarm
• 💡 Pro Tips for Mastery: Why teams commit a stability dump into source control
• Summary
• Practical Questions
• Stability Configuration: Controlling Inference for External Types
• The Problem with External Types
• Creating the Configuration File
• Configuring the Build
• How the Compiler Uses the Configuration
• Comparing with Alternatives
• From CLI Flag to Matcher: The Plugin Pipeline
• Practical Patterns for the Configuration File
• When Not to Use the Configuration File
• Verifying the Configuration with Compiler Reports
• Configuration and Multi-Module Builds
• 💡 Pro Tips for Mastery: Two opposite-looking ways to make a model stable, and why both are correct
• Summary
• Practical Questions
• Debugging Recomposition with Composition Tracing
• The Recomposition Debugging Workflow
• Layout Inspector Recomposition Counts
• Composition Trace Markers
• What the Trace Markers Show
• How Trace Markers Work Under the Hood
• Connecting Reports to Runtime Behavior
• Adding Custom Trace Sections
• What Trace Markers Cannot Show
• Summary
• Practical Questions
• Chapter 1 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] Compiler Fundamentals

• Exercise: Compose Compiler Fundamentals

• Quiz: Compiler Fundamentals Concepts

3 attempts allowed

• [Advanced Quiz] Compiler Fundamentals

• Advanced Quiz: Compiler Fundamentals Mastery

3 attempts allowed

• [Chapter 2] Compiler Internals
• Chapter Overview
• The Compose Compiler Plugin Architecture
• Why a Compiler Plugin
• K1 vs K2 Frontend Support
• ComposeIrGenerationExtension: The Core Hook
• The Orchestration of Lowering Passes
• Summary
• Practical Questions
• The IR Transformation Pipeline
• Pass 1: ComposableLambdaAnnotator (K2 Only)
• Pass 2: ClassStabilityTransformer
• Pass 3: LiveLiteralTransformer
• Pass 4: ComposableFunInterfaceLowering
• Pass 5: DurableFunctionKeyTransformer
• Pass 6: ComposableDefaultParamLowering
• Pass 7: ComposerLambdaMemoization
• Pass 8: ComposerParamTransformer
• Pass 9: ComposableTargetAnnotationsTransformer
• Pass 10: ComposerIntrinsicTransformer
• Pass 11: ComposableFunctionBodyTransformer
• Summary
• Practical Questions
• Composer Parameter Injection
• The Basic Transformation
• How the Transformer Works
• Call Site Rewriting
• Function Type Transformation
• Why Nullable Composer?
• Summary
• Practical Questions
• The $changed Bitmask: Tracking Parameter Mutations
• Bit Encoding Scheme
• Multiple $changed Parameters
• How the Caller Populates $changed
• How the Callee Uses $changed
• Tracing the Bits Through a Call Chain
• In Practice: How Stable Parameters Enable O(1) Skip Checks
• Summary
• Practical Questions
• Composable Function Body Transformation
• The Restart Group Wrapper
• A Multi Parameter Example
• Phase 1: The startRestartGroup Call
• Phase 2: The Dirty Bits Calculation
• Phase 3: The Conditional Execution
• Phase 4: The Update Scope
• Handling Non Restartable Functions
• Read Only Composable Optimization
• Control Flow: Replace Groups for Conditionals
• Control Flow: Replace Groups for Loops
• Nested Control Flow
• When Expressions and Early Returns
• The Companion Annotations
• @NonRestartableComposable
• @NonSkippableComposable
• @ReadOnlyComposable
• @ExplicitGroupsComposable
• @DisallowComposableCalls
• Summary
• Practical Questions
• Durable Function Keys
• Why Keys Must Be Durable
• Key Generation Algorithm
• Key Collisions
• Keys and the Slot Table
• Source Information for Tooling
• Durable Keys Across Incremental Compilation
• Keys for Composable Calls Inside Expressions
• Key Stability Across Multiplatform Targets
• Summary
• Practical Questions
• Live Literals: How the Compiler Enables Literal Hot Swap
• The Developer Experience
• How LiveLiteralTransformer Works
• Multiple Literals in a Single Function
• Durable Keys for Literal Identification
• Why Live Literals Only Works for Constants
• The Transformation in Context
• Production Builds
• Numeric and Boolean Literals
• Limitations and Practical Considerations
• Live Literals and the Broader Compiler Pipeline
• Beyond Live Edit: Compose Hot Reload
• Summary
• Practical Questions
• The Complete Picture: Tracing a Composable Through All Passes
• The Source Function
• Pass by Pass
• The Final Output
• Summary
• Practical Questions
• Chapter 2 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] Compiler Internals

• Exercise: Compose Compiler Internals

• Quiz: Compiler Internals Concepts

3 attempts allowed

• [Advanced Quiz] Compiler Internals

• Advanced Quiz: Compiler Internals Mastery

3 attempts allowed

• [Chapter 3] Runtime State and Effects
• Chapter Overview
• Remember and Caching
• Caching in Production Code
• What the Compiler Does With remember
• The Cache Function
• The RememberObserver Lifecycle
• How Keys Invalidate Cached Values
• remember, rememberSaveable, and retain: Three Memory Tiers
• Inside retain: Stores, Observers, and Keys
• Summary
• Practical Questions
• State Management: mutableStateOf and the State Record System
• The SnapshotMutableStateImpl Implementation
• Thread Safety Through Snapshot Isolation
• SnapshotStateList and SnapshotStateMap
• Summary
• Practical Questions
• Derived State: Lazy Computation With Dependency Tracking
• How Dependency Tracking Works
• Why This Is More Efficient Than remember
• When to Use Derived State
• The ResultRecord Structure
• In Practice: When derivedStateOf Saves Real Frames
• Summary
• Practical Questions
• Effects: Side Effects in a Declarative World
• SideEffect: After Every Successful Composition
• DisposableEffect: Lifecycle Aware Side Effects
• LaunchedEffect: Coroutine Scoped Side Effects
• When a Keyed Effect Does Not Need a Coroutine
• The Common Pattern
• Effect Ordering Guarantees
• 💡 Pro Tips for Mastery: What rememberUpdatedState actually is, and why it stops effects from restarting
• Summary
• Practical Questions
• CompositionLocal: Implicit Data Passing Through the Tree
• Two Variants: Static and Dynamic
• Providing Values
• ValueHolder Types
• How Consumption Works
• The Auxiliary Data Slot
• Provider Invalidation Strategies
• 💡 Pro Tips for Mastery: When does staticCompositionLocalOf recompose your whole subtree?
• Summary
• Practical Questions
• Bridging State and Flow: snapshotFlow, collectAsState, and produceState
• collectAsState: From Flow to Snapshot State
• collectAsStateWithLifecycle: The Android Lifecycle Aware Variant
• produceState: The General Purpose Bridge
• snapshotFlow: From Snapshot State to Flow
• The Circular Bridge
• When to Use Each
• 💡 Pro Tips for Mastery: produceState is a LaunchedEffect with DisposableEffect-style cleanup
• 💡 Pro Tips for Mastery: derivedStateOf and snapshotFlow are the same idea wearing two hats
• Summary
• Practical Questions
• Recomposition Scope: What Actually Gets Re-Executed
• Restart Groups Define the Boundary
• What Makes a Composable Restartable
• Narrowing the Scope With State Reads
• 💡 Pro Tips for Mastery: How Compose Itself Defers Reads, From State Objects to Lambdas
• How the Runtime Tracks Which Scope Reads Which State
• The Skip Mechanism Inside Restart Groups
• Tracing Recomposition in Practice
• Lambdas and Non Restartable Composables
• Practical Guidelines
• Summary
• Practical Questions
• Common State Pitfalls: Why the Runtime Behaves the Way It Does
• Pitfall 1: Plain var vs mutableStateOf
• Pitfall 2: Reacting to State Changes Inside LaunchedEffect
• Pitfall 3: Moving a remember Call Inside an if
• Pitfall 4: Object Allocation in Parameters
• Pitfall 5: derivedStateOf Without remember
• Summary
• Practical Questions
• Chapter 3 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] Runtime State and Effects

• Exercise: Runtime State and Effects Fundamentals

• Quiz: Runtime State and Effects Concepts

3 attempts allowed

• [Advanced Quiz] Runtime State and Effects

• Advanced Quiz: Runtime State and Effects Mastery

3 attempts allowed

• [Chapter 4] Runtime Internals
• Chapter Overview
• The Composer: Orchestrating Composition
• The Compiler Facing API
• The Implementation: GapComposer and LinkComposer
• Two Phase Composition: Record and Apply
• How a Composable Function Interacts with the Composer
• Summary
• Practical Questions
• The SlotTable: A Gap Buffer for UI State
• Group Encoding: Five Integers per Group
• The Gap Buffer Pattern
• Address, Anchor, and Index
• Why a Gap Buffer?
• SlotReader and SlotWriter
• Slot Table Operations in Practice
• In Practice: What the Slot Table Means for Your Code
• From Gap Buffer to Link-List: The Evolution of the Slot Table
• Summary
• Practical Questions
• Groups: The Building Blocks of Composition
• Group Types and Their Purposes
• How Groups Form a Tree in a Flat Array
• Group Keys and Identity Tracking
• Navigating Groups During Recomposition
• Summary
• Practical Questions
• The Snapshot System: Isolation Through MVCC
• The Snapshot Hierarchy
• Thread Local Snapshots and snapshot.enter { }
• How Reads and Writes Work
• SnapshotStateObserver: From State Change to Recomposition
• How Invalidations Propagate
• The SnapshotIdSet: Efficient Set Operations
• The State Record System
• In Practice: Snapshot Aware Debugging
• Summary
• Practical Questions
• The Recomposer: Scheduling and Executing Recomposition
• State Machine
• The Invalidation Pipeline
• InvalidationResult
• The MonotonicFrameClock
• The Main Loop
• How Recomposition Targets Specific Scopes
• Summary
• Practical Questions
• The Applier: Bridging Runtime and Trees
• Navigation: down and up
• Two Phase Insertion
• ComposeNode: The Bridge Composable
• Enabling Multiple Targets
• The AbstractApplier Base Class
• How Changes Reach the Applier
• Summary
• Practical Questions
• MovableContent: Preserving State Across Tree Moves
• How Movement Works
• The Data Structures
• Invalidation Forwarding
• Use Cases
• The Movement Protocol in Detail
• Summary
• Practical Questions
• Testing with Snapshots: Controlling Time and State in Tests
• The Test Frame Clock
• composeTestRule and the Idle Loop
• Atomic State Setup with withMutableSnapshot
• Testing Effects and Time Dependent Behavior
• Testing Derived State and Recomposition Counts
• The Underlying Mechanism
• Summary
• Practical Questions
• Chapter 4 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] Runtime Internals

• Exercise: Compose Runtime Internals

• Quiz: Runtime Internals Concepts

3 attempts allowed

• [Advanced Quiz] Runtime Internals

• Advanced Quiz: Runtime Internals Mastery

3 attempts allowed

• [Chapter 5] UI Layout System
• Chapter Overview
• Modifier Order: Why Sequence Changes Everything
• Two Snippets, Two Results
• Summary
• Practical Questions
• LayoutNode: The Central Element of the UI Tree
• Tree Structure and Parent Child Relationships
• Virtual Nodes: Transparent Composition Grouping
• Key Properties That Define Behavior
• Connecting to the Compose Runtime Through ComposeUiNode
• The Applier: Creating and Inserting LayoutNodes
• Summary
• Practical Questions
• The Modifier System: From Modifier to Modifier.Node
• The Modifier Interface: Composition Through Folding
• From Modifier.Element to Modifier.Node
• Rebuilding the Example as a Node
• NodeChain: Managing the Modifier Chain
• Structural Diffing with Myers Diff
• The DelegatableNode Contract and Delegation
• Node Lifecycle: Attach, Detach, and Reset
• NodeKind: Bit Based Classification for Efficient Dispatch
• Core Node Interfaces
• In Practice: Debugging Modifier Chains
• Summary
• Practical Questions
• Creating Custom Modifier.Node Implementations
• The Modern Pattern: ModifierNodeElement
• Implementing a DrawModifierNode
• Exposing the Modifier as an API
• Implementing a LayoutModifierNode
• The Old Pattern Versus the New Pattern
• Node Lifecycle Hooks
• Combining Multiple Node Interfaces
• Summary
• Practical Questions
• The Coordinator Chain: Measure and Layout Delegation
• NodeCoordinator: The Abstract Base
• The Coordinator Chain Architecture
• InnerNodeCoordinator: The Innermost Wrapper
• LayoutModifierNodeCoordinator: Custom Layout Modifiers
• Position Transformation
• How the Coordinator Chain Processes Measurement
• Summary
• Practical Questions
• The Measurement and Layout Pipeline
• MeasureAndLayoutDelegate: The Orchestrator
• LayoutState: Tracking the Current Phase
• The Three Pass Architecture
• MeasurePassDelegate: Performing Actual Measurement
• Place Ordering and Depth Sorting
• Alignment Line Calculations
• The Constraint System: How Constraints Propagate
• Intrinsic Measurements: Pre Measurement Queries
• 💡 Pro Tips for Mastery: Why Modifier.offset { } skips two whole phases that Modifier.offset() does not
• Summary
• Practical Questions
• Building Custom Layouts with the Layout Composable
• The Layout Composable: Creating a LayoutNode
• MeasurePolicy: The Core Contract
• Building a Vertical Flow Layout
• How Layout Connects to the Node Tree
• Intrinsic Measurements: Playing Well with Parents
• ParentData: Communication from Child to Layout
• When to Use Layout Versus SubcomposeLayout
• Summary
• Practical Questions
• SubcomposeLayout: Dynamic Composition During Measurement
• Why SubcomposeLayout Is Needed
• SubcomposeLayoutState: Managing Subcompositions
• A Composition Inside a Composition
• The Thread Back to the Parent
• Pausable Composition
• PrecomposedSlotHandle: Cached Composition
• State Machine
• Integration with the Lookahead System
• In Practice: Performance Implications of SubcomposeLayout
• Summary
• Practical Questions
• Lazy Layouts: How LazyColumn Builds on SubcomposeLayout
• LazyLayout: The Foundation Primitive
• Three Tiers of Item Lifecycle
• How Measurement Drives Composition
• Prefetch Scheduling
• Item Animations
• Why LazyColumn Is Faster Than a Large Column
• Content Types and Reuse Optimization
• In Practice: Performance Pitfalls
• Connecting the Pieces
• Summary
• Practical Questions
• Chapter 5 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] UI Layout System

• Exercise: UI Layout System Fundamentals

• Quiz: UI Layout System Concepts

3 attempts allowed

• [Advanced Quiz] UI Layout System

• Advanced Quiz: UI Layout System Mastery

3 attempts allowed

• [Chapter 6] UI Rendering and Interaction
• Chapter Overview
• The Rendering Pipeline: From Draw Calls to Pixels
• The Draw Pass Flow
• LayoutNodeDrawScope: The Reused Drawing Context
• Graphics Layers: Hardware Accelerated Rendering
• Layer Recording and Invalidation
• Mapping to the Android Rendering Pipeline
• 💡 Pro Tips for Mastery: How a graphicsLayer { } lambda animates without ever recomposing
• 💡 Pro Tips for Mastery: Why a fade-out gradient needs a graphicsLayer(alpha = 0.99f) in front of it
• Summary
• Practical Questions
• Input and Gesture Handling: From Touch to Composable
• PointerInputEventProcessor: The Entry Point
• The Hit Testing Pipeline
• Recursive Hit Testing Through the Tree
• Touch Target Expansion: Minimum Touch Targets
• HitPathTracker: Maintaining the Hit Path Tree
• Event Dispatch: Three Pass Processing
• One Modifier on Top of the Whole Pipeline
• Summary
• Practical Questions
• Nested Scrolling: How Scroll Events Flow Through the Modifier Chain
• NestedScrollConnection: The Four Callbacks
• The Four Phase Dispatch
• NestedScrollSource: Where the Scroll Came From
• A Practical Example: Collapsible Toolbar
• How Dispatch Flows Through the Modifier Chain
• Nested Scrolling with View Interop
• Connection to the Input System
• In Practice: Debugging Nested Scroll Issues
• Summary
• Practical Questions
• Focus Management: Keyboard Navigation and Focus Traversal
• Focus Hierarchy
• Focus Search Algorithms
• Focus Event Flow
• Android View Focus Integration
• Summary
• Practical Questions
• Semantics and Accessibility: Making Compose Accessible
• SemanticsOwner: Managing the Semantics Tree
• SemanticsNode: Wrapping LayoutNode with Semantic Data
• SemanticsModifierNode: The Provider Interface
• Android Accessibility Integration
• 💡 Pro Tips for Mastery: Why a hand-drawn Canvas is invisible to screen readers until you clearAndSetSemantics
• Summary
• Practical Questions
• The Lookahead System: Predictive Measurement for Animation
• Two Pass Measurement Architecture
• The Approach Phase: Animating Toward Targets
• LookaheadScope: Defining the Lookahead Boundary
• Detached Lookahead for SubcomposeLayout
• Enabling Shared Element Transitions
• Summary
• Practical Questions
• Shared Element Transitions: From LookaheadScope to SharedTransitionScope
• SharedTransitionLayout: The Container
• Marking Elements as Shared
• Integration with Navigation
• The Four Phase Transition
• How the Approach Node Drives the Animation
• sharedBounds Versus sharedElement
• ResizeMode: Performance Tradeoffs
• Connection to the Lookahead System
• Debugging Shared Element Transitions
• The Shared Element API: Small Surface, Large Machine
• What Runs Underneath
• The One Idea That Makes It Composable: A Key Registry
• Why the Surface Has Exactly the Parameters It Has
• Built From Parts You Already Met
• Summary
• Practical Questions
• Android Integration: AndroidComposeView and the Platform Bridge
• AndroidComposeView: The Root of Everything
• Composition Lifecycle Management
• Input Event Routing
• Text Input Integration
• Coordinating with Android View Measurement
• OwnerSnapshotObserver: Watching State for Invalidation
• Embedding Compose Within Traditional Android Views
• Graphics Context Management
• Summary
• Practical Questions
• Building Your Own Compose UI: The Runtime, Your Tree
• The One Fact That Makes This Possible
• Step 1: The Node, Which Is Your LayoutNode
• Step 2: The Applier, Which Is Your UiApplier
• Step 3: Composable Primitives via ComposeNode
• Step 4: Driving It, Which Is Your setContent Plus Recomposer
• Step 5: Measure, Layout, and Draw, the Part the Runtime Does Not Do
• Step 6: Watching Recomposition Actually Happen
• What You Just Skipped, and Where the Real Toolkit Adds It
• Summary
• Practical Questions
• Chapter 6 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] UI Rendering and Interaction

• Exercise: UI Rendering and Interaction Fundamentals

• Quiz: UI Rendering and Interaction Concepts

3 attempts allowed

• [Advanced Quiz] UI Rendering and Interaction

• Advanced Quiz: UI Rendering and Interaction Mastery

3 attempts allowed

• [Chapter 7] Performance Foundations
• Chapter Overview
• Three Rendering Phases: Where Performance Costs Live
• The Composition Phase
• The Layout Phase
• The Drawing Phase
• Phase Independence and Cost Hierarchy
• Recomposition Cascades
• Summary
• Practical Questions
• Stability Inference: The 12 Phase Algorithm
• Algorithm Overview
• Type Level Analysis: Phases 1 Through 4
• Class Level Analysis: Phases 5 Through 12
• Expression Level Stability
• Putting It All Together: Tracing ChatMessage
• Summary
• Practical Questions
• The Skip Decision: From Stability to Execution
• ParamState: The Five States of a Parameter
• The Dirty Bits Calculation in Detail
• Default Parameters and Skipping
• The Skip Condition
• Strong Skipping: Generated Code Comparison
• When Strong Skipping Does Not Help
• End to End Trace: UserProfile Recomposition
• The Interaction Between Parameters and State
• Summary
• Practical Questions
• Stability Patterns: Making Your Types Skip Friendly
• Data Classes with Stable Fields
• Immutable Collections
• The Stability Configuration File
• Multi Module Stability Concerns
• @Stable vs @Immutable: Choosing the Right Annotation
• @Stable on Functions, Not Just Types
• Decision Tree: Which Approach to Use
• Verifying Stability Changes
• When Stability Is Redundant
• Summary
• Practical Questions
• State Reads: Where You Read Determines What Recomposes
• Recomposition Scope Boundaries
• Deferred State Reads with Lambda
• derivedStateOf: Reducing Invalidation Frequency
• 💡 Pro Tips for Mastery: The remember that makes the copy-pasted isScrollingUp() helper actually work
• State Hoisting and Read Placement
• Summary
• Practical Questions
• Chapter 7 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] Performance Foundations

• Exercise: Performance Foundations Fundamentals

• Quiz: Performance Foundations Concepts

3 attempts allowed

• [Advanced Quiz] Performance Foundations

• Advanced Quiz: Performance Foundations Mastery

3 attempts allowed

• [Chapter 8] Performance in Practice
• Chapter Overview
• Lambda Recomposition: When Event Handlers Trigger Rebuilds
• When Lambdas Cause Recomposition
• Strong Skipping Memoization
• The Fun Interface Pattern
• Practical Lambda Guidelines
• Summary
• Practical Questions
• Measuring Performance: From Compiler Reports to CI Validation
• The Investigation Workflow
• Compiler Reports for Performance Investigation
• Composition Tracing at Runtime
• Layout Inspector Recomposition Counts
• Compose Stability Analyzer: IDE Plugin and Gradle Integration
• IDE Plugin: Real Time Stability Feedback
• Gradle Plugin: Runtime Tracing with @TraceRecomposition
• Stability Validation: CI Regression Prevention
• How the IDE Plugin Computes Stability Before You Build
• Performance Benchmarking with Macrobenchmark
• Hero Benchmarks: Measuring Whole User Journeys
• Common Debugging Scenarios
• Summary
• Practical Questions
• Anti Patterns: Six Ways to Accidentally Slow Down Compose
• Anti Pattern 1: Creating Objects in Composition
• Anti Pattern 2: Reading State in the Wrong Scope
• Anti Pattern 3: Unstable ViewModel References
• Anti Pattern 4: Missing Keys in Lazy Layouts
• Anti Pattern 5: Nested Lazy Layouts Along the Same Axis
• Anti Pattern 6: Animation State Reads During Composition
• Summary
• Practical Questions
• Advanced Techniques: When Stability Is Not Enough
• When Recomposition Is Not the Bottleneck
• Modifier.Node for Custom Modifier Performance
• graphicsLayer for Isolated Rendering
• Lazy Layout Optimization
• 💡 Pro Tips for Mastery: Why production list apps pass fadeInSpec = null to Modifier.animateItem()
• SubcomposeLayout Performance Considerations
• Reducing Allocation Pressure
• 💡 Pro Tips for Mastery: How a MutableState silently boxes on every frame
• Baseline Profiles for Startup Performance
• Summary
• Practical Questions
• Case Study: Optimizing a Chat Message List
• The Original Problem
• Step 1: Fix Stability
• Step 2: Add Keys and Content Types
• Step 3: Restructure State Reads
• Step 4: Stabilize Lambdas
• The Result
• Measuring the Improvement
• Applying the Pattern to Other Screens
• Summary
• Practical Questions
• Chapter 8 Recap
• Chapter Summary
• Key Terms
• Important Concepts
• What to Remember
• [Quiz] Performance in Practice

• Exercise: Performance in Practice Fundamentals

• Quiz: Performance in Practice Concepts

3 attempts allowed

• [Advanced Quiz] Performance in Practice

• Advanced Quiz: Performance in Practice Mastery

3 attempts allowed

• Final Words
• Glossary
• The Compose Compiler
• The Compose Runtime
• Compose UI
• Performance