ViewPager animation fade in/out instead of slide

Question

I got the FragmentBasics example from here. Is there a way make the ViewPager animation simply fade in and out when I swipe instead of sliding left and right? I've been trying some stuff with PageTransformer, but no success, I can still see it sliding. So I guess I need to somehow force its position to stay put, while sliding my finger only affects the alpha.

public class SecondActivity extends Activity {  SectionsPagerAdapter mSectionsPagerAdapter;  ViewPager mViewPager;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_second);      // Create the adapter that will return a fragment for each of the three     // primary sections of the activity.     mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());      // Set up the ViewPager with the sections adapter.     mViewPager = (ViewPager) findViewById(R.id.pager);     mViewPager.setPageTransformer(false, new FadePageTransformer());     mViewPager.setAdapter(mSectionsPagerAdapter); }  @Override public boolean onCreateOptionsMenu(Menu menu) {      // Inflate the menu; this adds items to the action bar if it is present.     getMenuInflater().inflate(R.menu.second, menu);     return true; }  @Override public boolean onOptionsItemSelected(MenuItem item) {     // Handle action bar item clicks here. The action bar will     // automatically handle clicks on the Home/Up button, so long     // as you specify a parent activity in AndroidManifest.xml.     int id = item.getItemId();     if (id == R.id.action_settings) {         return true;     }     return super.onOptionsItemSelected(item); }  public class SectionsPagerAdapter extends FragmentPagerAdapter {      public SectionsPagerAdapter(FragmentManager fm) {         super(fm);     }      @Override     public Fragment getItem(int position) {         // getItem is called to instantiate the fragment for the given page.         // Return a PlaceholderFragment (defined as a static inner class below).         return PlaceholderFragment.newInstance(position + 1);     }      @Override     public int getCount() {         // Show 3 total pages.         return 3;     }      @Override     public CharSequence getPageTitle(int position) {         Locale l = Locale.getDefault();         switch (position) {         case 0:             return getString(R.string.title_section1).toUpperCase(l);         case 1:             return getString(R.string.title_section2).toUpperCase(l);         case 2:             return getString(R.string.title_section3).toUpperCase(l);         }         return null;     } }  public static class PlaceholderFragment extends Fragment {     /**      * The fragment argument representing the section number for this fragment.      */     private static final String ARG_SECTION_NUMBER = "section_number";      /**      * Returns a new instance of this fragment for the given section number.      */     public static PlaceholderFragment newInstance(int sectionNumber) {         PlaceholderFragment fragment = new PlaceholderFragment();         Bundle args = new Bundle();         args.putInt(ARG_SECTION_NUMBER, sectionNumber);         fragment.setArguments(args);         return fragment;     }      public PlaceholderFragment() {     }      @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {         View rootView = inflater.inflate(R.layout.fragment_second, container, false);         TextView textView = (TextView) rootView.findViewById(R.id.section_label);         textView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));         return rootView;     } }  public class FadePageTransformer implements ViewPager.PageTransformer {         public void transformPage(View view, float position) {              if (position < -1 || position > 1) {                 view.setAlpha(0);             }             else if (position <= 0 || position <= 1) {                 // Calculate alpha. Position is decimal in [-1,0] or [0,1]                 float alpha = (position <= 0) ? position + 1 : 1 - position;                 view.setAlpha(alpha);             }             else if (position == 0) {                 view.setAlpha(1);             }         }     } 

Answer 1

This should work better for the fade in/out transform:

public void transformPage(View view, float position) {     view.setTranslationX(view.getWidth() * -position);             if(position <= -1.0F || position >= 1.0F) {         view.setAlpha(0.0F);     } else if( position == 0.0F ) {         view.setAlpha(1.0F);     } else {          // position is between -1.0F & 0.0F OR 0.0F & 1.0F         view.setAlpha(1.0F - Math.abs(position));     } }