How to delete current action bar tab? - tabs

Question

I have created swiping tabs and have added a method to remove a given tab at a position . It works fine if I try to remove any tab other than current tab .In that case, the code throws IllegalStateException. PLease let me know what is my mistake .
Following is my code :
public class TabsAdapter extends FragmentPagerAdapter implements ActionBar.TabListener, ViewPager.OnPageChangeListener {
private final Context mContext;
private final ActionBar mActionBar;
private final ViewPager mViewPager;
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
private final String TAG = "TABS_ADAPTER";
final class TabInfo {
private final Class<?> clss;
private final Bundle args;
TabInfo(Class<?> _class, Bundle _args) {
clss = _class;
args = _args;
}
}
public TabsAdapter(FragmentActivity activity, ViewPager pager) {
super(activity.getSupportFragmentManager());
mContext = activity;
mActionBar = activity.getActionBar();
mViewPager = pager;
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
TabInfo info = new TabInfo(clss, args);
tab.setTag(info);
tab.setTabListener(this);
mTabs.add(info);
mActionBar.addTab(tab);
notifyDataSetChanged();
}
public int getCount() {
return mTabs.size();
}
public Fragment getItem(int position) {
TabInfo info = mTabs.get(position);
return Fragment.instantiate(mContext, info.clss.getName(), info.args);
}
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
public void onPageSelected(int position) {
mActionBar.setSelectedNavigationItem(position);
}
public void onPageScrollStateChanged(int state) {
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
mViewPager.setCurrentItem(tab.getPosition());
Log.v(TAG, "clicked");
Object tag = tab.getTag();
for (int i=0; i<mTabs.size(); i++) {
if (mTabs.get(i) == tag) {
mViewPager.setCurrentItem(i);
}
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {}
public void onTabReselected(Tab tab, FragmentTransaction ft) {}
public void onTabReselected(Tab tab, android.app.FragmentTransaction ft) {}
#Override
public void onTabSelected(Tab tab, android.app.FragmentTransaction ft) {
Object tag = tab.getTag();
for (int i=0; i<mTabs.size(); i++) {
if (mTabs.get(i) == tag) {
mViewPager.setCurrentItem(i);
}
}
}
public void onTabUnselected(Tab tab, android.app.FragmentTransaction ft) {}
public void removeTab(ActionBar.Tab tab) {
mTabs.remove(tab.getTag());
mActionBar.removeTab(tab);
//mTabs.remove(mViewPager.getCurrentItem());
//mActionBar.removeTabAt(mViewPager.getCurrentItem());
notifyDataSetChanged();
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
// TODO Auto-generated method stub
super.destroyItem(container, position, object);
FragmentManager manager = ((Fragment) object).getFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.remove((Fragment) object);
trans.commit();
}
}
Following is the logcat error :
06-26 15:57:00.149: E/AndroidRuntime(17064): FATAL EXCEPTION: main
06-26 15:57:00.149: E/AndroidRuntime(17064): java.lang.IllegalStateException: The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 3, found: 2 Pager id: com.sparktg.weather:id/pager Pager class: class android.support.v4.view.ViewPager Problematic adapter: class com.sparktg.weather.TabsAdapter

Answer 1

I figured my mistake. I was trying to delete the current tab without providing an alternate tab to be displayed . In that schema of things, a user could have well deleted all the tabs , which is not advisable . Hence , in my removeTab() method of the adapter , I just set the current view to some default tab before deleting the current / any other tab . However , In such a scenario , the user should not have an option to delete that default tab .
Following is my improved method :
public void removeTab(ArrayList<String> tabNames){
Log.v(TAG, "Inside removeTab method of TabsAdpater");
Log.v(TAG, "Current Tab is at position " + mViewPager.getCurrentItem());
mViewPager.setCurrentItem(0);
Log.v(TAG, "Current Item is now set at position " + mViewPager.getCurrentItem());
for (int i=1; i<mTabNames.size(); i++){
for (int j=0;j<tabNames.size();j++){
if(tabNames.get(j).equals(mTabList.get(i).getText().toString())){
Log.v(TAG, "Tabs to be removed are : " + tabNames.get(j));
mTabs.remove(mTabList.get(i).getTag());
mActionBar.removeTab(mTabList.get(i));
mTabNames.remove(mTabList.get(i).getText());
mTabList.remove(mTabList.get(i));
notifyDataSetChanged();
}
}
}
}