Glitches in Mobile Development: Causes, Diagnosis, and Fixing Methods

What Is a Glitch in Mobile Development

Glitch is a short-term application malfunction where the app continues to function but behaves unexpectedly for the user. In mobile development, glitches occupy an intermediate position between lag and ANR: the app does not freeze or slow down, but displays an incorrect state.

Difference Between Glitch, Bug, and Lag

A bug is any code error that leads to unexpected behavior. Glitch is a type of bug that manifests as a temporary UI or logic distortion without complete functionality failure. A lag, in turn, is related to performance: the interface works slowly but correctly. Glitches affect correctness, not speed.

Typical Manifestations

The most common symptoms of glitches are flickering elements during list updates, incorrect data display after screen rotation, spontaneous button triggering, double invocation of an action, and UI state desynchronization with the data model. Each of these symptoms points to a specific class of logical errors.

Main Causes of Glitches in Apps

According to Firebase Crashlytics analytics, about 40% of non-fatal errors in mobile apps are related to race conditions and incorrect lifecycle handling. Let us examine the key sources of glitches.

Race Conditions in Multithreaded Code

When multiple threads simultaneously read and write the same data, the operation result becomes unpredictable. On Android, a typical scenario is updating UI from a background thread without synchronization, which leads to IllegalStateException or incorrect display. On iOS, a similar problem occurs when accessing shared mutable state from different Grand Central Dispatch queues.

Incorrect Lifecycle Handling

Mobile apps go through many states: foreground, background, screen rotation, Activity or ViewController recreation. If the code does not handle these transitions, glitches occur — for example, a Flow subscription leak after Activity destruction or animation launch on an invisible screen.

Data Binding Errors

When using Data Binding (Android) or Combine (iOS), incorrect configuration of reactive connections leads to UI desynchronization with the data model. Glitch manifests as a frozen value on the screen or, conversely, infinite component updates.

• Android — LiveData without LifecycleOwner, incorrect coroutine scope, ViewModelStore leak
• iOS — retain cycle in Combine closures, improper Cancellable management, strong reference in singletons
• Cross-platform — unhandled exceptions in async chains, context loss during reconfiguration

How to Diagnose Glitches on Android and iOS

Diagnosing glitches requires a combination of profiling tools, logging, and scenario reproduction. Let us examine the main approaches for each platform.

Diagnostic Tools on Android

Android Studio offers Layout Inspector for checking the UI hierarchy in real time — it shows which attributes are set for each View and whether there are discrepancies with expected values. Debug GPU Overdraw detects excessive redraws that often accompany visual glitches. Logcat with error tag filtering helps track the sequence of events that led to the failure.

Diagnostic Tools on iOS

Xcode provides View Debugger for UI layer inspection: you can see the CALayer hierarchy, check frames, constraints, and affine transforms. Time Profiler in Instruments shows which methods consume CPU time and whether there are main thread blockages. Main Thread Checker automatically detects UIKit calls from background threads — one of the main causes of glitches on iOS.

Log and Crash Report Analysis

Integrating Crashlytics (Firebase) or Sentry allows collecting stack traces of non-fatal errors and analyzing them across app versions, devices, and usage scenarios. For glitches that do not lead to crashes, it is useful to implement custom logging of key events: model state changes, network request calls, and screen transitions.

To add custom logging in an Android app, use the Log.w approach with a contextual tag:

class GlitchTracker {
    companion object {
        private const val TAG = "GlitchTracker"
    }

    fun trackStateMismatch(expectedState: String, actualState: String) {
        if (expectedState != actualState) {
            Log.w(TAG, "State mismatch: expected=$expectedState, actual=$actualState")
        }
    }
}

Methods for Eliminating Unstable Behavior

Eliminating glitches requires a systematic approach: from checking the data model state to architecture refactoring. Below are proven techniques for Android and iOS.

Reactive UI-to-Data Binding

The main cause of glitches is desynchronization between the app state and its display. Using reactive approaches (StateFlow on Android, @Published on iOS) ensures that the UI automatically updates when data changes. This eliminates a whole class of errors related to manual value setting.

Immutable Data Models

When a data model is mutable, any part of the code can change it at any time, leading to unpredictable states. Immutable data classes in Kotlin and structs in Swift guarantee that after object creation its state will not change, and all updates happen through creating a new copy. This radically reduces the likelihood of glitches related to data races.

UI Tests for Key Scenarios

Unit tests cover business logic but do not verify UI behavior. Espresso (Android) and XCUITest (iOS) allow automating the verification of key scenarios: button press, list update, screen rotation. Regression UI tests catch glitches at the CI stage before they reach production.

Example of an Android test with Espresso to verify correct text update after button press:

@Test
fun testButtonClickUpdatesText() {
    onView(withId(R.id.button_submit))
        .perform(click())

    onView(withId(R.id.text_result))
        .check(matches(withText("Submitted")))
}

Preventing Glitches During Development

The best way to fight glitches is to prevent them from appearing. Preventive measures cover architecture, code review, and static analysis tools.

Strict Typing and Sealed Classes

Using sealed class in Kotlin and enum with associated values in Swift allows modeling finite UI states: Loading, Success, Error. The compiler checks that all states are handled in when or switch, eliminating forgotten branches — a common source of glitches.

Unidirectional Data Flow

Architectures with unidirectional data flow (MVI on Android, TCA on iOS) ensure that data moves in one direction: from model through business logic to UI. Glitches in such architecture are practically impossible because there are no feedback loops that could change state in an unpredictable way.

Code Review with Checklist

Add items to the code review process: lifecycle handling check, data race protection, UI boundary state testing. Static analyzers Detekt (Android) or SwiftLint (iOS) automatically detect potentially dangerous patterns: force unwrap, incorrect background UI access, potential deadlocks.

• Android — Detekt, Android Lint, StrictMode during debugging
• iOS — SwiftLint, Xcode Analyze, Main Thread Checker
• Cross-platform — Danger with custom rules, SonarQube for metric accumulation