Improve Android App Performance

最新推荐文章于 2025-12-25 12:00:31 发布

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#android #性能 #app

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本文详细介绍了改善Android应用性能的10种关键策略，包括内存泄漏管理、使用UI线程、利用现有库、优化大型JSON解析、避免系统滥用、了解废弃API、自定义手套版本、架构设计和理解APK细节。这些方法旨在提高应用的流畅性和稳定性。

According to Droidcon NYC 2015 : 10 ways to improve your Android app performance
Boris Farber | YouTube | SlideShare

Attention: If you have a small app forget this article.

1.Memory Leaks

a.Listener’s Leak

public class LeakActivity extends Activity{
//...
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    NastyManager.getInstance().addListener(this);
  }
}

a.Fix Listener’s Leak

@Override
public void OnDestroy(){
  super.onDestroy();
  NastyManager.getInstance().removeListener(this);
}

b.Activity Leaks

public class MainActivity extends Activity {
  //...
  Handler handler;
  @Override
  protected void onCreate(Bundle savedInstacneState) {
    super.onCreate(savedInstanceState);
    //...
    handler = new Handler() {
      @Override
      public void handleMessage(Message msg){
        //...
      }
    }
    //What happens if handler.postDelayed(...)
  }
}

b.Fix Activity’s Leaks

private static class FixedHandler extends Handler {
  private final WeakReference<MainActivity> mActivity;
  //...
  public FixedHandler(MainActivity activity) {
    mActivity = new WeakReference<MainActivity>(activity);
    //...
  }
  @Override
  public void handlerMessage(Message msg) {}
  //...
}

c Static References
- Activities/Fragments etc - they have a life cycle
- Activity will not be GC-ed
- Static references - become dangling “pointers”
- m_staticActivity = staticFragment.getActivity();
c.Fix Prefer static to non static inner classes
- Non static Handler –> Activity leak
- Both classes have a different lifetime
d.what you can do Activity Leaks -1
- Remove away static references
- Use event bus
- Unregister listeners
- Prefer static inner classes to non static ones
d.what you can do Activity Leaks -2
- Do code reviews
- Understand your app structure
- Use tools
- Print logs on callbacks

2.Use UI Thread only for UI

Symptons

Scrolling

Not on UI thread

Images
Networking
JSON (next bullet) (Use libraries)
Database access (Use Loaders)

3.Use libraries

Use libraries

Already solve the problem
Requires specialization (easy to make mistake)
- Threading
- Memory
- Networking
- Images
Don’t lose focus
Develop your solution for a good reason
Common Async Http
- Volley
- OkHttp
- Retrofit
Image Loading
- Glide
- Picasso
- Fresco
- UIL
Pick 3rd party lib checklist
- Solves your problem
- Plays nicely with your current dependencies
- Dex method count
- Dependencies
- Maintenance
- Runtime permissions

4.Large JSONs

Large json

Parsing has a performance effect
Converted to class with getters and setters

JSON

Small JSONs - GSON is the best
Large JSONs -
- FastJson
- Jackson
- GSON + immutables type adapters

So.Scrolling
+ Keep UI thread only for UI
+ Understand concurrency APIs
+ Use libraries (memory, caching, json…)
+ Use loaders

5.System abuse

System Abuse

Don’t call private APIs by reflection
Don’t call private native methods (NDK/C level)
Don’t use Runtime.exex
“adb shell am” to communicate with other process is not something we want to support
Don’t abuse the System
Know and use APIs