Enrique Lopez Manas "Android High Performance"
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Android High Performance Enrique López Mañas Google Developer Expert & IT Consultor
Transcript of Enrique Lopez Manas "Android High Performance"
Android High Performance
Enrique López Mañas
Google Developer Expert & IT Consultor
How it did start?
Performance
"how well a person, machine, etc. does a piece of work or an activity"
Cambridge
But what is high performance?
• Strategies to create efficient software
Layout
Energy and battery
Security
Multithreading Programming patterns
Debugging techniques
Why is important?
• User Engagement
• Costs
• Maintenance
• Quality
3 Important Limits
0.1s 1s 10s
[Miller 1968; Card et al. 1991]:
What this means in Android?
ANR
ANR
• No response for input event in 5 seconds
• BroadCast receiver still executing after 10 seconds
How to avoid it?
Background operations? Show feedback!
How to avoid it?
Splash Screen?
How to avoid it?
Calculations? Worker thread!
How to avoid it?
Systrace! TraceView!
Debug
DDMS
Networking
Layouts
TV: 24fps(NTSC), 25fps(PAL)
New cam-coders / slow motion: 48fps+
Blur can occur!
Apps: 60fps!
every 16 ms!
Layouts
Layouts
Reusing layouts
Reusing layouts
Reusing layouts
ViewStub
ViewStub.inflate() View.setVisibility()
ViewStub
Hierarchy Viewer
Profile GPU Rendering
Profile GPU Rendering
• Blue: draw • Purple: prepare • Red: process • Orange: execute
Memory
“the ability to remember information, experiences, and people"
Cambridge
Memory - Enumerations
Memory - Enumerations
Memory - Enumerations
Memory - Enumerations
Memory - Enumerations @IntDef
Memory - Enumerations @IntDef
Memory - Enumerations Summary
• Unnecessary allocations • AVOID USING THEM • Change as much as possible with static final integer values
Memory - Constants
Constants in the code should be static and final to take advantage of memory savings and to avoid initialization in Java compiler
Memory - Strings
Memory - Strings
Memory - Strings
Memory Leaks
“a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations in such a way that memory which is no longer needed is not released.” Wikipedia
Memory Leaks - static fields
Memory Leaks - static fields
Memory Leaks - non-static inner classes
Memory Leaks - WeakReference
Threading
“Threading is a method of hair removal originating in Asia.”
Wikipedia
Threading
“is the smallest sequence of programmed instructions that can be managed independently by a scheduler”
Wikipedia
Threading
• AsyncTask • Loader • Threads…
Know your war!
Threading - AsyncTask
Communicate Worker Thread with UI
Does not need to communicate UI? Does not need to notify user? DOES NOT NEED ASYNCTASK!
If the AsyncTask has all parameters Void, you are only implementing doInBackground() and you do not need an AsyncTask
Threading - AsyncTaskLoader
Use it to fetch data
Same features as AsyncTask…
…plus the Activity life-cycle independency and data caching
Threading - AsyncTaskLoader
Threading - Services
• Not threads! • Executed in UI Thread by default • Never start a long running operation! • Lifecycle
Threading - IntentService
• Particular implementation of a Service • Execute sequential operations in background • Don’t need to handle the lifecycle
Networking
“process of communication between different terminal nodes to exchange data”
Me
Networking - best practices
Latency Gauging
Networking - best practices
Batch connections
• Wait, collect and send • (Analytics)
Networking - best practices
Pre-fetch
• Download as much as possible • (specially if idle connection)
Networking - best practices
Queuing connections
Networking - best practices
Caching responses
Networking - best practices
Last modified
Networking - best practices
Exponential back-off
