SingleFragmentActivity.java

package com.andrewpham.android.khanacademy_learnanything.controllers;

import android.app.ActionBar;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;

import com.andrewpham.android.khanacademy_learnanything.R;

/**
 * Created by Andrew on 19/08/2014.
 */
public abstract class SingleFragmentActivity extends FragmentActivity {

    private ActionBar mActionBar;

    protected abstract Fragment createFragment();

    protected int getLayoutResId() {
        return R.layout.activity_fragment;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mActionBar = getActionBar();
        mActionBar.setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.actionbar_background)));
        mActionBar.setDisplayShowTitleEnabled(false);
        setContentView(getLayoutResId());
        FragmentManager fm = getSupportFragmentManager();
        Fragment fragment = fm.findFragmentById(R.id.fragmentContainer);

        if (fragment == null) {
            fragment = createFragment();
            fm.beginTransaction()
                    .add(R.id.fragmentContainer, fragment)
                    .commit();
        }
    }

}