Question

Is my following Action bar Tab implementation method is efficient or not? Because whenever i switch between tabs the Tab content fragments are replaced and load again in frame layout.

I want to add fragments at first time itself and show the fragments smoothly(without reloading) when switch between tabs.

Note: i tried to add all fragments on onCreate method.But the fragments are overlapped with each other and display all fragments in frame layout at same time.

My Code:

public class ManageActivity extends SherlockFragmentActivity implements ActionBar.TabListener {

    private Activity mActivity;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_manage);

        getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        ActionBar.Tab tab1 = getSupportActionBar().newTab();
        tab1.setText("Tab1");
        tab1.setTabListener(this);
        getSupportActionBar().addTab(tab1);

        ActionBar.Tab tab2 = getSupportActionBar().newTab();
        tab2.setText("Tab2");
        tab2.setTabListener(this);
        getSupportActionBar().addTab(tab2);

        ActionBar.Tab tab3 = getSupportActionBar().newTab();
        tab3.setText("Tab3");
        tab3.setTabListener(this);
        getSupportActionBar().addTab(tab3);
    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        String selectedtab = tab.getText().toString();

        if(selectedtab.equalsIgnoreCase("Tab1"))
        {
            getSupportFragmentManager().beginTransaction().replace(R.id.tabfragment_container, new Tab1Fragment()).commit();
        }
        else if (selectedtab.equalsIgnoreCase("Tab2")) {
            getSupportFragmentManager().beginTransaction().replace(R.id.tabfragment_container, new Tab2Fragment()).commit();
        } 
        else if (selectedtab.equalsIgnoreCase("Tab3")){
            getSupportFragmentManager().beginTransaction().replace(R.id.tabfragment_container, new Tab3Fragment()).commit();
        }
    }

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub
    }
}

activity_manage.xml:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/tabfragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ManageActivity" >
</FrameLayout>

Note: My Tab contents are Listfragments which query data from Sqlite using loader manager.

Answer 1

I use a ViewPager that contains all my fragments. Every time a tab is selected I only switch the position in the Viewpager.

   @Override
   public void onTabSelected(Tab tab, FragmentTransaction ft) {
      int position = adapter.findItemPosition(this.id);
      ViewPager viewPager = (YourActivity)getActivity().getViewPager(); // Convenience method
      if (viewPager != null) {
         viewPager.setCurrentItem(position, this.shouldScroll);
      } else {
         Log.d(getClass().getSimpleName(), "No pager available");
      }
   }

To make this code working you need a Viewpager and have to add all tabs into the ViewPager through an instance of PagerAdapter. I use a FragmentPagerAdapter as there are not that many tabs most of the time.

This also enables your user to swipe through the tabs. If the user changes the selected tab through swiping you need to update the selected tab. I use ActionBarSherlock in all of my Apps. Therefore the next Snippet uses a supportActionBar. This code example is a simple listener that can be set on the ViewPager to update tab changes through swiping.

   private final class TabPageChangedListener extends ViewPager.SimpleOnPageChangeListener {

      @Override
      public void onPageSelected(int position) {
         ActionBar actionBar = getSupportActionBar();
         if (actionBar != null) {
            actionBar.setSelectedNavigationItem(position);
         } else {
            Log.e(getClass().getSimpleName(),
                  "No actionbar available to change selected tab.");
         }
      }
   }

There is also the possibility to disable swiping by overwriting the ViewPager and intercepting the swiping touch motions if you do not want the tabs to be swipeable.