Android: How to change icon+title when a certain tab gets selected?

Question

I have made a sliding tab layout and there is an icon and text on each tab , spanned using "SpannableStringBuilder" so now it shows the icon and title together like one object, Now when a certain tab gets selected i want to replace that icon with another. My code is as follows:

public class SectionsPagerAdapter extends FragmentPagerAdapter  {

    final int PAGE_COUNT = 4;
    private String tabTitles[] = new String[]{"Logs", "Rewards", "News", "Rank"};

    private int myImageList[] = new int[]{R.drawable.logs, R.drawable.rewards, R.drawable.news, R.drawable.ranking};

    private Context context;
    ArrayList<Fragment> fragments = new ArrayList<>();

    public SectionsPagerAdapter(FragmentManager fm, Context context) {
        super(fm);
        this.context = context;
        this.fragments.add(ActivityList.newInstance(""));
        this.fragments.add(OfferedRewardActivity.newInstance(""));
        this.fragments.add(NewsActivity.newInstance(""));
        this.fragments.add(RankActivity.newInstance(""));
    }

    @Override
    public int getCount() {
        return PAGE_COUNT;
    }


    @Override
    public Fragment getItem(int position) {
        return this.fragments.get(position);
    }

    public int getDrawableId(int position) {
        return myImageList[position];
    }

    Drawable myDrawable;
    String title;

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                myDrawable = getResources().getDrawable(R.drawable.logs);
                title = tabTitles[0];
                break;
            case 1:
                myDrawable = getResources().getDrawable(R.drawable.rewards);
                title = tabTitles[1];
                break;
            case 2:
                myDrawable = getResources().getDrawable(R.drawable.news);
                title = tabTitles[2];
                break;
            case 3:
                myDrawable = getResources().getDrawable(R.drawable.ranking);
                title = tabTitles[3];
                break;

            default:
                break;
        }
        SpannableStringBuilder sb = new SpannableStringBuilder("        "  +"   \n"+ title); // space added before text for convenience
        try {
            myDrawable.setBounds(1, 1, myDrawable.getIntrinsicWidth(), myDrawable.getIntrinsicHeight());
            ImageSpan span = new ImageSpan(myDrawable, DynamicDrawableSpan.ALIGN_BASELINE);
            sb.setSpan(span, 0, 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
        } catch (Exception e) {
            // TODO: handle exception
        }
        return sb;
    }
}

and the code for populatetabscript() is:

private void populateTabStrip() {
    final PagerAdapter adapter = mViewPager.getAdapter();
    final OnClickListener tabClickListener = new TabClickListener();

    for (int i = 0; i < adapter.getCount(); i++) {
        View tabView = null;
        TextView tabTitleView = null;

        if (mTabViewLayoutId != 0) {
            // If there is a custom tab view layout id set, try and inflate it
            tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, mTabStrip,
                    false);
            tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId);
        }

        if (tabView == null) {
            tabView = createDefaultTabView(getContext());
        }

        if (tabTitleView == null && TextView.class.isInstance(tabView)) {
            tabTitleView = (TextView) tabView;
        }

        if (mDistributeEvenly) {
            LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) tabView.getLayoutParams();
            lp.width = 0;
            lp.weight = 1;
        }

        tabTitleView.setText(adapter.getPageTitle(i));
        tabView.setOnClickListener(tabClickListener);
        String desc = mContentDescriptions.get(i, null);
        if (desc != null) {
            tabView.setContentDescription(desc);
        }

        mTabStrip.addView(tabView);
        if (i == mViewPager.getCurrentItem()) {
            tabView.setSelected(true);
        }
    }
}

I have Googled alot but didn't find anything or maybe I left something or misunderstood. What should i do to achieve this?