title: How to call a function after activity is loaded
body: <p>I have an activity in android with a RecyclerView. I am trying to call getChildAt(i) on the RecyclerView in OnCreate but it returns null. I tried the same thing inside a button click listener that I created for testing and it returns the item fine. This must be due to the fact that the RecyclerView has not loaded its children at this point in the OnCreate and I need to access its first child while the activity is loading. Is there any form of listener that I can use to check once the activity is loaded and the RecyclerView's children are created without a manual button press as the activity is loaded? I am unable to find a suitable listener for the activity or the RecyclerView.</p>
  
  <p>Here is my base code:</p>
  
  <pre><code>@Override
  protected void onCreate(Bundle savedInstanceState)
  {
      super.onCreate(savedInstanceState);
  
      mainRec = (RecyclerView) findViewById(R.id.cardList);
      mainRec.setHasFixedSize(true);
  
      lm = new LayoutManager(this);
  
      mainRec.setLayoutManager(lm);
      mainRecAdap = new HappyAdapter(db.getListData(), this);
      mainRec.setAdapter(mainRecAdap);
  
      //this is where I am trying to call getChildAt
  
  }
  
  @Override
  protected void onPause()
  {
      super.onPause();
      restoreState();
  }
  
  @Override
  protected void onResume()
  {
      super.onResume();
      restoreState();
  }
  
  @Override
  public boolean onCreateOptionsMenu(Menu menu)
  {
      getMenuInflater().inflate(R.menu.menu_list, menu);
      return true;
  }
  
  private void restoreState()
  {
      setToolbarColor(backgroundColour);
  }
  
  
  @Override
  public void onBackPressed()
  {
      super.onBackPressed();
      overridePendingTransition(R.anim.fade_forward, R.anim.right_slide_out);
  }
  
  @Override
  protected int getLayoutResource()
  {
      return R.layout.activity_list;
  }
  </code></pre>
  
  <p>Thanks</p>