try adding image on tab bar and then change the url of image on tab
change.
Like:
Image[] images = new Image[n];
images[0] = new Image();
img1.setURL("active.png");
tabBar.addTab(img1);
images[1] = new Image();
images[1].setURL("inactive.png");
tabBar.addTab(images[1]);
and so on for rest of the tab.
and then on tabChange:
public void onTabSelected(SourcesTabEvents bar, int index) {
images[index].setURL("active.png");
//set url of other images to 'inactive.png'
}
-Bakul