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POWhy would an AsyncTask's postExecute method not run in the UI thread?
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  1. POWhy would an AsyncTask's postExecute method not run in the UI thread?
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    copied!<p>I have a nested inner class that extends AsyncTask to run a db query in the background. In the post execute method I am calling a parent's method to update the view something like this</p> <pre><code>private class QueryRunner extends AsyncTask&lt;Void,Void,Cursor&gt; { @Override protected Cursor doInBackground(Void... voids) { return getContentResolver().query(LeadContentProvider.buildUri(app.getEntityId()),new String[]{LeadContentProvider._ID},null,null,LeadContentProvider.LEAD_STATUS_DATETIME +" desc"); } @Override protected void onPostExecute(Cursor c) { onCursorLoaded(c); } } </code></pre> <p>The onCursorLoaded method looks like:</p> <pre><code>private void onCursorLoaded(Cursor c) { mPagerAdapter = new LeadDetailsFragmentPagerAdaper(getSupportFragmentManager()); mPager.setAdapter(mPagerAdapter); mPager.setCurrentItem(iIndex, false); } </code></pre> <p>Most of the time this works fine - but some users have crashes with this stack trace:</p> <pre><code>java.lang.IllegalStateException: Must be called from main thread of process at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1392) at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:431) at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:139) at android.support.v4.view.ViewPager.populate(ViewPager.java:804) at android.support.v4.view.ViewPager.setAdapter(ViewPager.java:344) at com.servicemagic.pros.activities.LeadDetails.onCursorLoaded(LeadDetails.java:205) at com.servicemagic.pros.activities.LeadDetails.access$200(LeadDetails.java:25) at com.servicemagic.pros.activities.LeadDetails$QueryRunner.onPostExecute(LeadDetails.java:196) at com.servicemagic.pros.activities.LeadDetails$QueryRunner.onPostExecute(LeadDetails.java:170) at android.os.AsyncTask.finish(AsyncTask.java:417) at android.os.AsyncTask.access$300(AsyncTask.java:127) at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:150) at android.os.HandlerThread.run(HandlerThread.java:60) </code></pre> <p>So - why is the postExecute() method not called on the MainThread?</p>
 

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