Progress bar in Tab View

I have created a tab view. What i want is that when i switch between 2 views of my tab a progress bar is generated. How can i do so.....

Here is my code:

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tab);

        Resources res = getResources(); // Resource object to get Drawables
        TabHost tabHost = getTabHost();  // The activity TabHost
        TabHost.TabSpec s开发者_Python百科pec;  // Resusable TabSpec for each tab
        Intent intent;  // Reusable Intent for each tab
        TabWidget tabs = new TabWidget(this);
        tabs.setId(android.R.id.tabhost);
        // Create an Intent to launch an Activity for the tab (to be reused)
        intent = new Intent().setClass(this, ImageExercise.class);

        // Initialize a TabSpec for each tab and add it to the TabHost
        spec = tabHost.newTabSpec("images").setIndicator("Images",
                          res.getDrawable(R.drawable.imageicon))
                      .setContent(intent);
        tabHost.addTab(spec);

        // Do the same for the other tabs
        intent = new Intent().setClass(this, AudioPlay.class);
        spec = tabHost.newTabSpec("songs").setIndicator("Songs",
                          res.getDrawable(R.drawable.audioicon))
                      .setContent(intent);
        tabHost.addTab(spec);

        intent = new Intent().setClass(this, VideoActivity.class);
        spec = tabHost.newTabSpec("videos").setIndicator("Videos",
                          res.getDrawable(R.drawable.videoicon))
                      .setContent(intent);
        tabHost.addTab(spec);

        tabHost.setCurrentTab(2);
    }

}