How to select previous tab which we have selected already in action bar?

How to select previous tab which we have selected already in action bar?

here my problem ill explain. I have added tabs in action bar all tabs
working properly by selecting and replacing fragments but when i click the
tab which i have selected previous tab which ill give error. here my code.
public class MainActivity extends Activity {
public static Context appContext;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
appContext = getApplicationContext();
ActionBar actionbar = getActionBar();
actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab connectionTab = actionbar.newTab().setText("Connection");
ActionBar.Tab masterDataTab = actionbar.newTab().setText("Master Data");
Fragment connection = new AFragment();
Fragment masterData = new BFragment();
connectionTab.setTabListener(new MyTabsListener(connection));
masterDataTab.setTabListener(new MyTabsListener(masterData));
actionbar.addTab(connectionTab);
actionbar.addTab(masterDataTab);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()) {
}
return false;
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
}
}
class MyTabsListener implements ActionBar.TabListener { public Fragment
fragment;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
Toast.makeText(MainActivity.appContext, "Reselected!",
Toast.LENGTH_LONG).show();
// ft.replace(R.id.fragment_container, fragment); }
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.fragment_container, fragment);
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.remove(fragment);
}
}