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POProper onDestroy() / How to avoid memory leaks
 

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  1. POProper onDestroy() / How to avoid memory leaks
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    <p>I read a number of articles on how to avoid memory-leaks in Android, but i'm still not quite sure if I got it right.</p> <ol> <li>My Application consists of a single <code>Activity</code>.</li> <li>I don't have any private or static members in that Activity, all code is started from within <code>onCreate()</code>.</li> <li>In have some self-contained static classes whose static instances sometimes hold references to a <code>Context</code> or <code>View</code>s. In my <code>onDestroy()</code> method, I set all of these instances to null.</li> <li>I recycle all of my <code>Bitmap</code>s.</li> </ol> <p><strong>Q1</strong>: Is that enough? </p> <p>What confuses me is the classic example of a no-go you can find on the net (<a href="http://www.curious-creature.org/2008/12/18/avoid-memory-leaks-on-android/" rel="noreferrer">http://www.curious-creature.org/2008/12/18/avoid-memory-leaks-on-android/</a>):</p> <pre><code>@Override protected void onCreate(Bundle state) { super.onCreate(state); TextView label = new TextView(this); label.setText("Leaks are bad"); setContentView(label); } </code></pre> <p>I thought that, as soon as <code>onCreate</code> finishes, <code>label</code> goes out of scope and is GCed. </p> <p><strong>Q2</strong>: How can this create a memory-leak?</p> <p>My Activity basically looks like this:</p> <pre><code>@Override public void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); /* Statics */ AssetUtils.initIndex(this); BitmapLoader.startInstance(this); /* frame */ ViewGroup frame = (ViewGroup) getLayoutInflater().inflate(R.layout.frame, null); this.setContentView(frame); /* create controller */ Controller controller = new Controller(frame, getLayoutInflater()); /* START */ controller.start(); } @Override public void onDestroy() { super.onStop(); /* Statics */ AssetUtils.destroyInstance(); BitmapLoader.destroyInstance(); } </code></pre> <p>Inside <code>Controller</code> I occasionally retrieve a <code>Context</code> using <code>View#getContext()</code> to pass it to manually created <code>View</code>s and the like. It's never stored statically somewhere, only in member-variables of classes which all go back to <code>Controller</code>. </p> <p><strong>Q3</strong>: Is there something I overlooked?</p>
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    1. COQ2: Have you observed a memory leak within your Activity?
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    2. CONot yet, though i don't know how I would observe one. I haven't got any error-messages and I haven't profiled my application yet. It's landscape-only (customer demand) so it won't be destroyed upon rotation.
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    3. COBut Q2 refers to this article: http://www.curious-creature.org/2008/12/18/avoid-memory-leaks-on-android/ which says "This means that views have a reference to the entire activity and therefore to anything your activity is holding onto; usually the entire View hierarchy and all its resources." But doesn't every View have a reference to a Context?
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