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    <p>I've also stumbled upon this and found a few advantages to using the arguments <code>Bundle</code> over instance fields:</p> <ul> <li><p>If it's in a <code>Bundle</code> the Android system knows about it and can create and destroy your <code>Fragment</code> (using the mandatory parameterless/default constructor and usual lifecycle methods), and just pass in the arguments bundle again. This way no arguments get lost on a low memory killing spree or the eventual orientation changes (this often hits me on first deploy to a real device after development in the less-rotating emulator).</p></li> <li><p>You can just pass the extras <code>Bundle</code> of an <code>Activity</code> as-is to a <code>Fragment</code> embedded in the layout; e.g. I often use this when I have an <code>Activity</code> that displays a <code>Fragment</code> "fullscreen" and needs some ID (or <code>ContentProvider</code> URI) to know what to display/do. I sometimes even add more stuff to a <code>Bundle</code> (or a copy) before I pass it on, e.g.</p> <pre><code>@Override protected void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (savedInstanceState == null) { // not a re-creation final Bundle args = new Bundle(getIntent().getExtras()); args.putInt(CoverImageFragment.BACKGROUND_RESOURCE, android.R.color.black); final Fragment fragment = CoverImageFragment.newInstance(args); getSupportFragmentManager() .beginTransaction() .add(android.R.id.content, fragment) .commit(); } } </code></pre></li> <li><p>It keeps the way of developing a <code>Fragment</code> close to that of an <code>Activity</code>, i.e. <code>Bundle</code> as "input parameters, no exceptions".</p></li> </ul> <p>As for the downsides you mentioned:</p> <ul> <li><p>I think the overhead is minimal because you most likely won't be querying the <code>Bundle</code> in a tight loop, so getting your argument data out once in <code>onCreate()</code>, <code>onViewCreate()</code>, etc. isn't that bad.</p></li> <li><p>For type-safety, <code>Bundle</code> has all the different <code>getXXXX()</code> methods, and even overloads to provide a default value if a something is missing/optional :)</p></li> </ul> <p>As for the <code>newInstance()</code> methods, I think of them as an easy way to encapsulate the <code>new</code> and <code>setArguments()</code> calls for my <code>Fragment</code>; I sometimes provide an additional <code>MyFragment newInstance(String singleIdOfWhatToDisplay)</code> that creates both the <code>Bundle</code> and <code>Fragment</code> in one go and returns a ready-to-go <code>Fragment</code> instance.</p>
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    1. POMember variables vs setArguments in Fragments
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    1. USPhilipp Reichart
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    1. COWhat does a newInstance method achieve what a constructor would not achieve? I can call `setArguments` from a constructor.
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      1. USMatthias
    2. CO@Matthias I think it's just better style to create factory methods in these situations...
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      1. USAlex Lockwood
    3. COnewInstance is not a factory method (as in the factory method pattern if that's what you mean--see http://en.wikipedia.org/wiki/Factory_method_pattern); it's static and hence cannot be overridden, nor is it generic with respect to the type it returns. From what I can tell it bears no advantage over using a constructor directly other than personal preference. However, I vaguely remember that Fragments need a default constructor? Perhaps the idea here is to not having to define 2 ctors, one taking the bundle arguments and one that's empty. Best guess.
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