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POAndroid PagerAdapter not calling instantiateItem
 

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  1. POAndroid PagerAdapter not calling instantiateItem
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    <p>I'm trying to implement ViewPager with PagerAdapter in my app. I'm mainly working off <a href="http://blog.stylingandroid.com/archives/537" rel="noreferrer">this example</a>.</p> <p>My <code>PagerAdapter</code> is called DataPagerAdapter and uses the following constructor and <code>instantiateItem</code>, where I inflate a view from <code>data_list_view.xml</code>:</p> <pre><code>public class DataPagerAdapter extends PagerAdapter implements TitleProvider { private LayoutInflater mInflater; private static String[] titles = new String[] { "Page 1", "Page 2", "Page 3" }; private final Context context; public DataPagerAdapter( Context context ) { this.context = context; } @Override public String getTitle( int position ) { return titles[ position ]; } @Override public int getCount() { return titles.length; } @Override public Object instantiateItem( View pager, int position ) { ListView v = (ListView) mInflater.inflate(R.layout.data_list_view, null); ((ViewPager)pager).addView( v, 0 ); return v; } @Override public void destroyItem( View pager, int position, Object view ) { ((ViewPager)pager).removeView( (ListView)view ); } @Override public boolean isViewFromObject( View view, Object object ) { return view.equals( object ); } @Override public void finishUpdate( View view ) {} @Override public void restoreState( Parcelable p, ClassLoader c ) {} @Override public Parcelable saveState() { return null; } @Override public void startUpdate( View view ) {} } </code></pre> <p>And in my activity I get my adapter:</p> <pre><code>DataPagerAdapter adapter = new DataPagerAdapter( this ); </code></pre> <p>And then later I want to refer to my dataListView in code:</p> <pre><code>dataListView = (ListView) findViewById(R.id.listViewData); </code></pre> <p>Problem is, the <code>dataListView</code> is returned as null by the <code>findViewById</code> call since the <code>instantiateItem</code> is never processed. </p> <p>When is <code>instantiateItem</code> called and is this done automatically (as the example seems to suggest) or do I have to force it somehow? </p>
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    1. COYou need to make sure you are filling out all of the methods in the PagerAdapter, such as getCount(), isViewFromObject(), etc. Could you add a bit more code to your question?
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    2. COI added the full code of the DataPagerAdapter. I basically tweaked the code used in the example from the link I provided.
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