The article provides tips and tools for optimising Android apps, focusing on performance issues that impact user experience. It highlights the importance of optimisation, noting that 86% of users uninstall apps after a single use due to poor performance. It also notes that users expect apps to load quickly, with 40 out of the top 100 apps starting in under 2 seconds. The article provides a list of performance tips and debugging tools to help improve app performance.
Performance Tips:
- String vs StringBuilder: Using StringBuilder for multiple string appends is more efficient than direct string concatenation due to the immutability of strings.
- Correct Data Type: Choosing the right data structure (e.g., ArrayList vs. Vector, Set for unique objects) based on the use case can improve performance.
- Location Updates: Use Google Location Services API, request only the necessary location precision and update frequency, and stop updates when not needed.
- Network Requests: Batch network requests to minimise battery consumption and mobile data usage. Consider using GCM Network Manager for scheduling tasks.
- Reflection: Cache responses when using reflection for backward compatibility, as reflection can be slow.
- Autoboxing: Avoid autoboxing (converting primitive types to Object types) by using primitive types directly or specialised collections like SparseIntArray.
- OnDraw: Optimise the onDraw() function by avoiding object allocation and minimising drawing operations.
- ViewHolders: Use the ViewHolder design pattern to smooth scrolling lists by caching view lookups.
- Resizing Images: Resize images before displaying them to avoid memory issues, and consider using third-party libraries like Picasso, Universal Image Loader, Fresco, or Glide.
- Strict Mode: Use Strict Mode during development to detect network requests or disk accesses on the main thread, but disable it in production builds.
Debugging Tools:
- Android Monitor: Built-in tool in Android Studio that provides graphs for Network, CPU, GPU, and Memory usage.
- GPU Overdraw: Tool in Developer Options that shows overdraw areas with different colours, indicating how many times an area was overdrawn.
- GPU Rendering: Tool in Developer options that displays coloured bars on the screen, representing the time spent on different rendering phases.
- Hierarchy Viewer: Tool for getting an overview of view hierarchies and identifying useless views or performance bottlenecks.
The article emphasises that optimising Android apps is complex and requires understanding the trade-offs of different approaches. It recommends staying updated with the latest tools and learning from top developers and companies.
