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![View.setTag(key,tag) - pre 4.0public static class MainActivity extends Activity { private final WeakHashMap<Parent, Parent.Child> mMap = new WeakHashMap<Parent, Parent.Child>(); @Override public void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); // If parents were collected OOM error wouldn't be thrown. But they aren't collected so we get OOM here. for (int i = 0; i < 1000; ++i) { final Parent parent = new Parent(); mMap.put( parent, parent.mChild ); } }}public static class Parent { public final Child mChild = new Child(); public class Child { private final byte[] mJunk = new byte[10*1024*1024]; }}](/image.pl?url=https%3a%2f%2fimage.slidesharecdn.com%2fmemoryanalyzertoolandmemoryoptimizationtipsin-121230065843-phpapp02%2f75%2fMemory-Analyzer-Tool-and-memory-optimization-tips-in-Android-26-2048.jpg&f=jpg&w=240)
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Александр Терещук - Memory Analyzer Tool and memory optimization tips in Android
The document discusses memory analysis and optimization tips for Android applications. It introduces the Eclipse Memory Analyzer tool, which can be used to analyze memory usage and find memory leaks. Some key points covered include the low RAM sizes on Android devices, how the garbage collector works, how to analyze an object's shallow size and retained size, finding memory dominators, and common memory leak pitfalls like non-static handlers and large bitmaps stored in static fields. The document encourages analyzing heap dumps in the Memory Analyzer tool to optimize memory usage and find leaks.
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Александр Терещук - Memory Analyzer Tool and memory optimization tips in Android
- 1.MEMORY ANALYZER TOOLANDMEMORY OPTIMIZATIONTIPS IN ANDROID Olexandr Tereshchuk
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- 3.ProblemLow RAM size – 256MB to 512MB on most of devices. Low CPU performance – harder to perform full GC. Each application works in it’s own process and VM instance. Large system library.
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- 5.Zygote – closerlook
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- 7.DEX – closerlook
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- 9.Garbage Collection:Concurrent Markand Sweep initial mark — stop-the-world. mark — Concurrent. preclean — Concurrent. remark — Stop-the-world. sweep — Concurrent.
- 10.Garbage Collection:Concurrent Markand Sweep
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- 12.Shallow sizeShallow sizeof an object is the amount of memoryallocated to store the object itself, not taking intoaccount the referenced objects == Sum of the size ofthe “object header” and the fields of an object
- 13.Retained size Retained set of X The set of objects that would be reclaimed, if we could delete Object X Retained size of X The Retained size of an object X is equal to the shallow size of the „Retained sets“ of X
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- 15.Dominator Tree X dominates Y, if all paths from a GC Root to Y go via X. “X is a Dominator of Y” The closest Dominator to Y is called “immediate Dominator”
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- 23.“Static” Drawableprivate staticDrawable sBackground; @Override protected void onCreate(final Bundle state) { super.onCreate(state); final TextView label = new TextView(this); label.setText("Leaks are bad"); if (sBackground == null) { sBackground = getDrawable(R.drawable.large_bitmap); } label.setBackground(sBackground); setContentView(label); }
- 24.Non-static Handler classpublicclass MyActivity extends Activity { Handler myhandler = new Handler() { ... }; }
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- 26.View.setTag(key,tag) - pre4.0public static class MainActivity extends Activity { private final WeakHashMap<Parent, Parent.Child> mMap = new WeakHashMap<Parent, Parent.Child>(); @Override public void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); // If parents were collected OOM error wouldn't be thrown. But they aren't collected so we get OOM here. for (int i = 0; i < 1000; ++i) { final Parent parent = new Parent(); mMap.put( parent, parent.mChild ); } }}public static class Parent { public final Child mChild = new Child(); public class Child { private final byte[] mJunk = new byte[10*1024*1024]; }}
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