title: Acces inner fragment method from its parent class
body: <p>is it possible to acces inner class method?</p>
  
  <pre><code>public class MenuFragment extends Fragment {
  
      RelativeLayout fullLayout;
  
      ImageView imgSettings;
  
      public static ImageView imgTopZigzag, imgBottomZigzag;
  
      MyPagerAdapter myPagerAdapter;
  
      ProgressBar levelProgressBar;
      TextView txtLevel, txtXp;
  
      public static int screenWidth, screenHeight;
  
      public static ViewPager mViewPager;
  
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
      }
  
      @Nullable
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
          final View rootView = inflater.inflate(R.layout.menu_fragment, null);
  
          mViewPager = (ViewPager) rootView.findViewById(R.id.view_pager);
  
          myPagerAdapter = new MyPagerAdapter(getChildFragmentManager());
  
          mViewPager.setAdapter(myPagerAdapter);
  
          fullLayout = (RelativeLayout) rootView.findViewById(R.id.rl_menu);
  
          imgSettings = (ImageView) rootView.findViewById(R.id.img_settings);
          imgSettings.bringToFront();
          imgSettings.getLayoutParams().height = 100;
          imgSettings.getLayoutParams().width = imgSettings.getLayoutParams().height;
  
          imgTopZigzag = (ImageView) rootView.findViewById(R.id.img_top_zigzag);
          imgBottomZigzag = (ImageView) rootView.findViewById(R.id.img_bottom_zigzag);
  
          levelProgressBar = (ProgressBar) rootView.findViewById(R.id.progressLevel);
          txtLevel = (TextView) rootView.findViewById(R.id.txt_level);
          txtXp = (TextView) rootView.findViewById(R.id.txt_xp);
          txtLevel.setTypeface(((MainActivity) getActivity()).typeface);
          txtXp.setTypeface(((MainActivity) getActivity()).typeface);
  
          Display display = getActivity().getWindowManager().getDefaultDisplay();
          screenWidth = display.getWidth();
          screenHeight = display.getHeight();
  
          final Animation showMenu = new AlphaAnimation(0, 1);
          showMenu.setDuration(600);
          showMenu.setFillAfter(true);
  
          final TranslateAnimation centerUpBack = new TranslateAnimation(0, 0, -screenHeight/3, -screenHeight/3 + screenHeight/10);
          centerUpBack.setDuration(400);
          centerUpBack.setFillAfter(true);
  
          TranslateAnimation centerUp = new TranslateAnimation(0, 0, 0, -screenHeight/3);
          centerUp.setDuration(1000);
          centerUp.setFillAfter(true);
          centerUp.setAnimationListener(new Animation.AnimationListener() {
              @Override
              public void onAnimationStart(Animation arg0) {
              }
  
              @Override
              public void onAnimationRepeat(Animation arg0) {
              }
  
              @Override
              public void onAnimationEnd(Animation arg0) {
                  imgTopZigzag.startAnimation(centerUpBack);
                  mViewPager.setVisibility(View.VISIBLE);
                  mViewPager.startAnimation(showMenu);
  
              }
          });
  
          final TranslateAnimation centerDownBack = new TranslateAnimation(0, 0, screenHeight/3, screenHeight/3 - screenHeight/10);
          centerDownBack.setDuration(400);
          centerDownBack.setFillAfter(true);
  
          final TranslateAnimation centerDown = new TranslateAnimation(0, 0, 0, screenHeight/3);
          centerDown.setDuration(1000);
          centerDown.setFillAfter(true);
          centerDown.setAnimationListener(new Animation.AnimationListener() {
              @Override
              public void onAnimationStart(Animation arg0) {
              }
  
              @Override
              public void onAnimationRepeat(Animation arg0) {
              }
  
              @Override
              public void onAnimationEnd(Animation arg0) {
                  imgBottomZigzag.startAnimation(centerDownBack);
              }
          });
  
          imgTopZigzag.startAnimation(centerUp);
          imgBottomZigzag.startAnimation(centerDown);
  
          updateLevelBar();
  
          mViewPager.getLayoutParams().width = screenWidth;
          mViewPager.getLayoutParams().height = mViewPager.getLayoutParams().width*17/25;
  
          return rootView;
      }
  
      public void updateLevelBar() {
          levelProgressBar.setMax(((MainActivity) getActivity()).level * 150);
          levelProgressBar.setProgress(((MainActivity) getActivity()).xp);
          txtLevel.setText("Level " + ((MainActivity) getActivity()).level);
          txtXp.setText(((MainActivity) getActivity()).xp + " / " + ((MainActivity) getActivity()).level * 150 + " xp");
      }
  
      public static class FragmentMenu extends Fragment {
          LinearLayout innerMenuLayout;
  
          TextView classicHighscore, zenHighscore;
  
          ImageButton btnPlayLast, btnLeaderboard;
          @Override
          public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
              View rootView = inflater.inflate(R.layout.menu_tab, container, false);
  
              innerMenuLayout = (LinearLayout) rootView.findViewById(R.id.linearLayout);
              innerMenuLayout.getLayoutParams().width = screenWidth*17/25;
  
              btnPlayLast = (ImageButton) rootView.findViewById(R.id.btn_play_last);
              btnLeaderboard = (ImageButton) rootView.findViewById(R.id.btn_leaderboard);
  
              classicHighscore = (TextView) rootView.findViewById(R.id.txt_classic_highscore);
              zenHighscore = (TextView) rootView.findViewById(R.id.txt_zen_highscore);
              classicHighscore.setTypeface(((MainActivity) getActivity()).typeface);
              zenHighscore.setTypeface(((MainActivity) getActivity()).typeface);
  
              final TranslateAnimation openTopLeaderboard = new TranslateAnimation(0, 0, - screenHeight/3 + screenHeight/10, -screenHeight/2 - 50);
              openTopLeaderboard.setDuration(800);
              openTopLeaderboard.setFillAfter(true);
  
              final TranslateAnimation openBottomLeaderboard = new TranslateAnimation(0, 0, screenHeight/3 - screenHeight/10, screenHeight/2 + 50);
              openBottomLeaderboard.setDuration(800);
              openBottomLeaderboard.setFillAfter(true);
  
              final Animation leaderboard = new AlphaAnimation(1, 0);
              leaderboard.setDuration(800);
              leaderboard.setFillAfter(true);
              leaderboard.setAnimationListener(new Animation.AnimationListener() {
                  @Override
                  public void onAnimationStart(Animation animation) {
                      imgTopZigzag.startAnimation(openTopLeaderboard);
                      imgBottomZigzag.startAnimation(openBottomLeaderboard);
                  }
  
                  @Override
                  public void onAnimationRepeat(Animation animation) {
                  }
  
                  @Override
                  public void onAnimationEnd(Animation animation) {
                      ((MainActivity) getActivity()).startLeaderboard();
                      MenuFragment.FragmentMenuPlay fragment = (MenuFragment.FragmentMenuPlay) getChildFragmentManager().findFragmentById(R.id.fragmentView);
                      fragment.buttonsSetClickable();
                  }
              });
  
              btnLeaderboard.setOnClickListener(new View.OnClickListener() {
                  @Override
                  public void onClick(View v) {
                      mViewPager.startAnimation(leaderboard);
                      MenuFragment.FragmentMenuPlay fragment = (MenuFragment.FragmentMenuPlay) getChildFragmentManager().findFragmentById(R.id.fragmentView);
                      fragment.buttonsSetUnclickable();
                  }
              });
  
              updateHighscores();
  
              return rootView;
          }
  
          public void updateHighscores() {
              SharedPreferences prefs = getContext().getSharedPreferences("com.thematus.twinz", Context.MODE_PRIVATE);
              int classic_highscore = prefs.getInt("classic_highscore", 0);
              int zen_highscore = prefs.getInt("zen_highscore", 0);
              classicHighscore.setText(classic_highscore + "");
              zenHighscore.setText(zen_highscore + "");
          }
      }
  
      public static class FragmentMenuPlay extends Fragment {
          LinearLayout innerMenuLayout;
  
          ImageButton btnClassicMode, btnZenMode, btnLocalMulti;
          @Override
          public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
              View rootView = inflater.inflate(R.layout.menu_play_tab, container, false);
  
              innerMenuLayout = (LinearLayout) rootView.findViewById(R.id.linearLayout);
              innerMenuLayout.getLayoutParams().width = screenWidth*17/25;
  
              btnClassicMode = (ImageButton) rootView.findViewById(R.id.btn_classic_mode);
              btnZenMode = (ImageButton) rootView.findViewById(R.id.btn_zen_mode);
              btnLocalMulti = (ImageButton) rootView.findViewById(R.id.btn_local_multi);
  
              final TranslateAnimation closeMenuTop = new TranslateAnimation(0, 0, - screenHeight/3 + screenHeight/10, 0);
              closeMenuTop.setDuration(300);
              closeMenuTop.setFillAfter(true);
  
              final TranslateAnimation closeMenuBottom = new TranslateAnimation(0, 0, screenHeight/3 - screenHeight/10, 0);
              closeMenuBottom.setDuration(300);
              closeMenuBottom.setFillAfter(true);
  
              final Animation hideMenuClassic = new ScaleAnimation(1f, 0.2f, 1f, 0.2f, Animation.RELATIVE_TO_SELF, (float) 0.5, Animation.RELATIVE_TO_SELF, (float) 0.5);
              hideMenuClassic.setDuration(300);
              hideMenuClassic.setFillAfter(true);
              hideMenuClassic.setAnimationListener(new Animation.AnimationListener() {
                  @Override
                  public void onAnimationStart(Animation animation) {
                      imgTopZigzag.startAnimation(closeMenuTop);
                      imgBottomZigzag.startAnimation(closeMenuBottom);
                  }
  
                  @Override
                  public void onAnimationRepeat(Animation animation) {
                  }
  
                  @Override
                  public void onAnimationEnd(Animation animation) {
                      ((MainActivity) getActivity()).startClassicMode();
                      buttonsSetClickable();
                  }
              });
  
              btnClassicMode.setOnClickListener(new View.OnClickListener() {
                  @Override
                  public void onClick(View v) {
                      mViewPager.startAnimation(hideMenuClassic);
                      buttonsSetUnclickable();
  
                  }
              });
  
              final Animation hideMenuZen = new ScaleAnimation(1f, 0.2f, 1f, 0.2f, Animation.RELATIVE_TO_SELF, (float) 0.5, Animation.RELATIVE_TO_SELF, (float) 0.5);
              hideMenuZen.setDuration(300);
              hideMenuZen.setFillAfter(true);
              hideMenuZen.setAnimationListener(new Animation.AnimationListener() {
                  @Override
                  public void onAnimationStart(Animation animation) {
                      imgTopZigzag.startAnimation(closeMenuTop);
                      imgBottomZigzag.startAnimation(closeMenuBottom);
                  }
  
                  @Override
                  public void onAnimationRepeat(Animation animation) {
                  }
  
                  @Override
                  public void onAnimationEnd(Animation animation) {
                      ((MainActivity) getActivity()).startZenMode();
                      buttonsSetClickable();
                  }
              });
  
              btnZenMode.setOnClickListener(new View.OnClickListener() {
                  @Override
                  public void onClick(View v) {
                      mViewPager.startAnimation(hideMenuZen);
                      buttonsSetUnclickable();
                  }
              });
  
              final Animation hideMenuLocalMulti = new ScaleAnimation(1f, 0.2f, 1f, 0.2f, Animation.RELATIVE_TO_SELF, (float) 0.5, Animation.RELATIVE_TO_SELF, (float) 0.5);
              hideMenuLocalMulti.setDuration(300);
              hideMenuLocalMulti.setFillAfter(true);
              hideMenuLocalMulti.setAnimationListener(new Animation.AnimationListener() {
                  @Override
                  public void onAnimationStart(Animation animation) {
                      imgTopZigzag.startAnimation(closeMenuTop);
                      imgBottomZigzag.startAnimation(closeMenuBottom);
                  }
  
                  @Override
                  public void onAnimationRepeat(Animation animation) {
                  }
  
                  @Override
                  public void onAnimationEnd(Animation animation) {
                      ((MainActivity) getActivity()).startLocalMulti();
                      buttonsSetClickable();
                  }
              });
  
              btnLocalMulti.setOnClickListener(new View.OnClickListener() {
                  @Override
                  public void onClick(View v) {
                      mViewPager.startAnimation(hideMenuLocalMulti);
                      buttonsSetUnclickable();
                  }
              });
  
              return rootView;
          }
  
          public void buttonsSetClickable() {
              btnClassicMode.setClickable(true);
              btnZenMode.setClickable(true);
              btnLocalMulti.setClickable(true);
          }
  
          public void buttonsSetUnclickable() {
              btnClassicMode.setClickable(false);
              btnZenMode.setClickable(false);
              btnLocalMulti.setClickable(false);
          }
      }
  
      class MyPagerAdapter extends FragmentPagerAdapter {
  
          public MyPagerAdapter(FragmentManager fragmentManager){
              super(fragmentManager);
  
          }
          @Override
          public android.support.v4.app.Fragment getItem(int position) {
              switch(position){
                  case 0:
                      FragmentMenu fm = new FragmentMenu();
                      return fm;
                  case 1:
                      FragmentMenuPlay fmp = new FragmentMenuPlay();
                      return fmp;
              }
              return null;
          }
  
          @Override
          public int getCount() {
              return 2;
          }
      }
  }
  </code></pre>
  
  <p>Is there any way to do it? I tried calling it by </p>
  
  <pre><code>MenuFragment.FragmentMenu fragment = (MenuFragment.FragmentMenu) getChildFragmentManager()
                                       .findFragmentById(R.id.viewPager);
                                        fragment.method();
  </code></pre>
  
  <p>but this returns null pointer exception.</p>
  
  <p>Also the problem could be that I'm using a view pager with inner classes (fragments).</p>
  
  <p>Thanks for any reply!</p>