Question

This is a wierd problem.

This will be a terrible question because I have little to no information.

About two days ago I had the ViewPagerAdapter working just fine. I could swipe and it would switch between views as defined by the adapter.

However, all of a sudden (not by itself, I’m sure I did something) the TitlePagerIndicator doesn’t snap to the headings and doesn’t display any content. By not snapping I mean that if I drag to the left, the title will sit at 3/4 of the screen instead of snapping to the side and displaying the next page (screenshot below).

I have debugged and instantiate item is called and a proper view is returned.

However, when I open the app I’m getting a lot of warnings like these:
VFY: unable to resolve virtual method 3015: Landroid/widget/LinearLayout;.getAlpha ()F
VFY: unable to resolve direct method 3011: Landroid/widget/LinearLayout;. (Landroid/content/Context;Landroid/util/AttributeSet;I)V
VFY: unable to resolve virtual method 2965: Landroid/widget/FrameLayout;.setAlpha (F)V

I’m assuming this is a problem with my imports, but everything compiles just fine, I have the ViewPagerIndicator as a library project, as well as Sherlock.

Here’s my adapter code:

public class ViewPagerAdapter extends PagerAdapter implements TitleProvider {

private static String[] titles = new String[] { 
    "My Klinks", 
    "Received Klinks"
    };

private final Context context;

public ViewPagerAdapter(Context context) {
    this.context = context;
}

public String getTitle(int position) {
    return titles[position];
}

@Override
public int getCount() {
    return titles.length;
}

@Override
public Object instantiateItem(View pager, int position) {
    TextView t = new TextView(context);
    t.setText("WheeeE");
    return t;
}

@Override
public void destroyItem(View pager, int position, Object view) {
    ((ViewPager) pager).removeView((TextView) 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) {
}
}

And here is my activity code:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.main );

    // set up the slidey tabs
    ViewPagerAdapter adapter = new ViewPagerAdapter( this );
    ViewPager pager = (ViewPager)findViewById( R.id.viewpager );
    TitlePageIndicator indicator = (TitlePageIndicator)findViewById( R.id.indicator );
    pager.setAdapter( adapter );
    indicator.setViewPager( pager );

    // set up the action bar
    final ActionBar ab = getSupportActionBar();

    ab.setBackgroundDrawable(getResources().getDrawable(R.drawable.ad_action_bar_gradient_bak));
}

Answer 1

If someone else gets the same problem:

In instantiateView: don’t forget to attach your new View to the ViewPager:

@Override
public Object instantiateItem(View pager, int position) {
    TextView t = new TextView(context);
    t.setText("WheeeE");
    ((ViewPager)pager).addView(t);
    return t;
}

The current version of instantiateItem gets a ViewGroup instead of a View, the solution should be the same.