title: Android ViewPager and FragmentStatePagerAdapter - not started on first item
body: <p>I have a View containing a list of items. When I click on a particular listitem, it shows the details of that particular object in a new activity (and a new fragment). That all works fine. </p>
  
  <p>Now I wanted to add a function, that the user can swipe from selected in detail activity shown item to the next/previous item, so he doesn't have to go back to the list and choose another item. I tried using ViewPager and FragmentStatePagerAdapter and it works and really has nice effects.</p>
  
  <p>My Activity.java:</p>
  
  <pre><code>    @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_exercise);
  
          // Instantiate a ViewPager and a PagerAdapter.
          mPager = (ViewPager) findViewById(R.id.pager);
          mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
          mPager.setAdapter(mPagerAdapter);
  
      ...
      }
  
     private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
          public ScreenSlidePagerAdapter(FragmentManager fm) {
              super(fm);
          }
  
          @Override
          public Fragment getItem(int position) {
          // pos is the position of the object in the list    
              Fragment fragment = ExerciseFragment.newInstance(exercisesArray, pos+position);
              return fragment;
          }
  
          @Override
          public int getCount() {
              return exercisesArray.size();
          }
      }
  </code></pre>
  
  <p>My questions:</p>
  
  <ol>
  <li><p>Is ViewPager the right way for my intention? Ever time the user swipes to next item, a new fragment is instantiated. The list can contain about 100 items... so maybe 100 fragments are created? Can this be a problem?</p></li>
  <li><p>My implementation only works fine, if the first item is selected and swiped. For example: I have 5 items in a list and the first one is clicked. Now I can swipe to second item, to third item, back to second. BUT if the user clicks on third item of the list, I can't swipe left to second and first item! Anyone have an idea?</p></li>
  </ol>
  
  <p>Thanks a lot!</p>