FragmentAdapter Example

FragmentAdapter.java

import java.util.ArrayList;
import java.util.List;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.ViewGroup;
import com.actionbarsherlock.app.ActionBar.Tab;
import com.actionbarsherlock.app.ActionBar.TabListener;
import com.actionbarsherlock.app.SherlockFragmentActivity;

public class FragmentAdapter extends FragmentPagerAdapter implements TabListener, ViewPager.OnPageChangeListener {
	public FragmentAdapter(SherlockFragmentActivity a, FragmentManager fm) {
		super(fm);
		this.mContext = a;
		this.mManager = fm;
		mPager = (ViewPager) a.findViewById(R.id.pager);
		mPager.setOnPageChangeListener(this);
		
	}
	SherlockFragmentActivity mContext;
	FragmentManager mManager;
	ViewPager mPager;
	
	static class FragmentInfo{
		public String fragment;
		public int stringId;
	}

	private List<FragmentInfo> fragments = new ArrayList<FragmentInfo>();

	@Override
	public Fragment getItem(int position) {
		return Fragment.instantiate(mContext, fragments.get(position).fragment);
	}
	
	public Fragment getCurrent(){
		return mManager.findFragmentByTag( makeFragmentName(mPager.getCurrentItem()) );
	}
	
	public void addFragment(Class<?> name, int string){
		FragmentInfo fi = new FragmentInfo();
		fi.fragment = name.getName();
		fi.stringId = string;
		fragments.add(fi);
		
		Tab tab = mContext.getSupportActionBar().newTab();
		tab.setText(string).setTabListener(this);
		mContext.getSupportActionBar().addTab(tab);
		
		notifyDataSetChanged();
	}

	@Override
	public int getCount() {
		return fragments.size();
	}
	
	private FragmentTransaction mCurTransaction;
	private Fragment mCurrentPrimaryItem;
	
    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        if (mCurTransaction == null) {
            mCurTransaction = mManager.beginTransaction();
        }
        mCurTransaction.detach((Fragment)object);
    }
	
	@Override
	public Object instantiateItem(ViewGroup container, int position) {
		if (mCurTransaction == null) {
			mCurTransaction = mManager.beginTransaction();
		}

		final long itemId = position;

		// Do we already have this fragment?
		String name = makeFragmentName(itemId);
		Fragment fragment = mManager.findFragmentByTag(name);
		if (fragment != null) {
			mCurTransaction.attach(fragment);
		} else {
			fragment = getItem(position);
			mCurTransaction.add(container.getId(), fragment,
					makeFragmentName(itemId));
		}
		
		if (mCurrentPrimaryItem != fragment) {
            fragment.setMenuVisibility(false);
            fragment.setUserVisibleHint(false);
        }

		return fragment;
	}
	
    @Override
    public void finishUpdate(ViewGroup container) {
        if (mCurTransaction != null) {
            mCurTransaction.commitAllowingStateLoss();
            mCurTransaction = null;
            mManager.executePendingTransactions();
        } else{
        	super.finishUpdate(container);
        }
    }
    
    @Override
    public void setPrimaryItem(ViewGroup container, int position, Object object) {
        Fragment fragment = (Fragment)object;
        if (fragment != mCurrentPrimaryItem) {
            if (mCurrentPrimaryItem != null) {
                mCurrentPrimaryItem.setMenuVisibility(false);
                mCurrentPrimaryItem.setUserVisibleHint(false);
            }
            if (fragment != null) {
                fragment.setMenuVisibility(true);
                fragment.setUserVisibleHint(true);
            }
            mCurrentPrimaryItem = fragment;
        }
    }

	private String makeFragmentName(long itemId) {
		return "page:" + itemId;
	}

	public void onTabSelected(Tab tab, FragmentTransaction ft) {
		mPager.setCurrentItem(tab.getPosition());
		mContext.invalidateOptionsMenu();
	}

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

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

	public void onPageScrollStateChanged(int arg0) {
		// TODO Auto-generated method stub
		
	}

	public void onPageScrolled(int arg0, float arg1, int arg2) {
		// TODO Auto-generated method stub
		
	}

	public void onPageSelected(int page) {
		mContext.getSupportActionBar().setSelectedNavigationItem(page);
		mContext.invalidateOptionsMenu();
	}

}