Mobile App Debugging

Debug mobile applications across iOS, Android, and cross-platform frameworks.

iOS Debugging (Xcode)

// Breakpoint with condition // Right-click breakpoint > Edit > Condition: userId == "123"

// LLDB commands po variable // Print object p expression // Evaluate expression bt // Backtrace

Memory Debugging

• Use Memory Graph Debugger to find retain cycles

• Enable Zombie Objects for use-after-free bugs

• Profile with Instruments > Leaks

Android Debugging (Android Studio)

// Logcat filtering Log.d("TAG", "Debug message") Log.e("TAG", "Error", exception)

// Filter: tag:MyApp level:error

Common Issues

• ANR: Check main thread blocking

• OOM: Profile with Memory Profiler

• Layout issues: Use Layout Inspector

React Native

// Remote debugging // Shake device > Debug JS Remotely

// Console logging console.log('Debug:', variable); console.warn('Warning'); console.error('Error');

// Performance Monitor // Shake > Show Perf Monitor // Target: 60 FPS, <16ms per frame

Network Debugging

// Intercept requests XMLHttpRequest.prototype._send = XMLHttpRequest.prototype.send; XMLHttpRequest.prototype.send = function() { console.log('Request:', this._url); this._send.apply(this, arguments); };

Debug Checklist

• Test on physical devices (not just simulators)

• Test on older device models

• Simulate slow 3G network

• Test offline mode

• Check memory under load

• Test rotation and safe areas

• Verify 60 FPS target

Performance Targets

Metric Target

Frame rate 60 FPS (16ms/frame)

Memory <100MB

App launch <2 seconds