protected void setCacheTitleBar(@NonNull final Geocache cache) {
        setTitle(TextUtils.coloredCacheText(this, cache, cache.getName() + " (" + cache.getShortGeocode() + ")"));
        final ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.setDisplayShowHomeEnabled(true);
            actionBar.setIcon(MapMarkerUtils.getCacheMarker(getResources(), cache, CacheListType.OFFLINE, Settings.getIconScaleEverywhere()).getDrawable());
        }
    }
change the titlebar icon and text to show the current geocache
main/src/main/java/cgeo/geocaching/activity/AbstractActivity.java