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POAccessing fragment method from async task
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  1. POAccessing fragment method from async task
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    copied!<p>First off, is this a good practice, accessing a fragment's method from an asynchronous task?</p> <p>I have an async task which generates a list of LatLng which is use in my fragment to draw a polyline. However, if i try to use a getter method to get the list.</p> <pre><code> public List&lt;LatLng&gt; getList() { return this.list; } </code></pre> <p>I get <code>nullpointerexceptions</code> so i have to perform this inside the fragment,</p> <pre><code>while(list == null) { // FIXME delay because of this list = getRoute.getList(); } </code></pre> <p>Which defeats the purpose of having a background task.</p> <p>Is there a way I can call the method from within the async task's post execute method?</p> <pre><code> @Override protected void onPostExecute(OTPResponseUI otpResponse) { Fragment.fragmentsMethod(getList()); mDialog.dismiss(); } </code></pre> <p>This way i can correctly show the process dialog and not leave the user hanging while it loads the list.</p> <p><strong>UPDATE</strong> I tried invoking a callback like <a href="http://blog.evoxmusic.fr/content/how-implement-callback-asynctask" rel="nofollow">this</a> but the callback function in my fragment is not executed.</p> <p><strong>UPDATE2</strong> Ok i just passed the fragment instance to the async task to be able to call the fragment method. As per your advice:</p> <blockquote> <p>Create the list object in your custom AsyncTask class, and then return it back to the Fragment in the postExecute() method. You can do this by directly calling a method on the Fragment instance (that you'll get either via the constructor. It works, thanks!</p> </blockquote>
 

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