ViewPager's fragment without activity context

Question

Functionality: I'm developing some sort of configuration wizard, which may have many steps. Each step has it's own configuration, in this case, isSkippable() whether if user can skip the step or not. And a callback method when user taps on menu item to go to next step, or indeed completed the wizard.

Issue: I don't have activity context, and my fields are also null when onStepCompleted is called from activity.

Activity which extends ActionBarActivity and doesn't implement any interface:

private WizardStepListener mStepListener;

private WizardPagerAdapter mPagerAdapter;
private ViewPager mViewPager;

public static Intent getIntent(final Context context) {
    final Intent intent = new Intent(context, WizardActivity.class);
    intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_CLEAR_TOP);
    return intent;
}

@Override
public boolean onOptionsItemSelected(final MenuItem item) {
    if (mStepListener == null) {
        return false;
    }

    switch (item.getItemId()) {
        case R.id.action_step_skip:
            moveToNextStep();

            break;

        case R.id.action_step_done:
        case R.id.action_step_next:

            final boolean stepCompleted = mStepListener.onStepCompleted();
            if (stepCompleted && !isLastStep() || !stepCompleted) {
                    break;
            }

            final Intent intent = LandingActivity.getIntent(this);
            WizardActivity.this.startActivity(intent);
            overridePendingTransition(R.anim.slide_in_right, R.anim.slide_out_right);
            WizardActivity.this.finish();

            break;

    }

    return true;
}

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

    final Resources resources = getResources();
    final PagerTabStrip pagerTabStrip = (PagerTabStrip) findViewById(R.id.pager_tab_strip);
    pagerTabStrip.setDrawFullUnderline(false);
    pagerTabStrip.setBackgroundColor(resources.getColor(R.color.tabs_categories_background));
    pagerTabStrip.setTextColor(Color.WHITE);
    pagerTabStrip.setTabIndicatorColor(Color.WHITE);

    mPagerAdapter = new WizardPagerAdapter(getSupportFragmentManager());
    mViewPager = (ViewPager) findViewById(R.id.wizard_pager);
    mViewPager.setAdapter(mPagerAdapter);
    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {

        @Override
        public void onPageSelected(final int position) {
            setupView(position);
        }

    });

    setupView(0);
}

private void setupView(final int position) {
    final Fragment fragment = mPagerAdapter.getActiveFragment(mViewPager, position);

    mStepListener =
            fragment instanceof WizardStepListener ? (WizardStepListener) fragment : null;

    supportInvalidateOptionsMenu();
}

private boolean isLastStep() { ... }

private boolean moveToNextStep() { ... }

}

Fragment which extends Fragment and implements LoaderManager.LoaderCallbacks>, WizardStepListener:

private CategoriesExpandableAdapter mCatAdapter;
private ViewFlipper mViewFlipper;

/**
 * @return A new instance of fragment WizardCategories.
 */
public static WizardCategories newInstance() {
    return new WizardCategories();
}

@Override
public boolean isSkippable() {
    return false;
}

@Override
public boolean onStepCompleted() {
    if (!isAdded()) {
        return false;
    }

    if (mCatAdapter == null || !mCatAdapter.hasCheckedCategories()) {

        FeedbackToast.getInstance(
                getActivity(),
                "Debes seleccionar al menos una categoría",
                FeedbackToast.NEGATIVE
        ).show();

        return false;
    }

    ...

    return true;
}

The PagerAdapter which extends FragmentPagerAdapter:

private final FragmentManager mFragmentManager;

public WizardPagerAdapter(final FragmentManager fm) {
    super(fm);
    mFragmentManager = fm;
}

@Override
public Fragment getItem(final int position) {
    final Fragment fragment;
    switch (position) {
        case 0:
            fragment = WizardCategories.newInstance();

            break;

        default:
            fragment = new Fragment();

            break;
    }

    return fragment;
}

public Fragment getActiveFragment(final ViewPager container, final int position) {
    final String name = makeFragmentName(container.getId(), position);
    final Fragment fragment = mFragmentManager.findFragmentByTag(name);
    return  fragment != null ? fragment : getItem(position);
}

private static String makeFragmentName(final int viewId, final int index) {
    return "android:switcher:" + viewId + ":" + index;
}

What I've tried:

• Changing PagerAdapter extends to FragmentStatePagerAdapter with no luck.
• Retrieving fragment from FragmentManager by using getActiveFragment seen in another maybe related posts.

Additional comments:

• Fragment's isAdded() always returns false.
• Calling getActivity() on fragment's onStepCompleted always returns null.

Answer 1

You should be able to use getActivity() to get the Activity and store the context in your fragment in onCreate, the main thing to remember is you need to call this after onAttach has been called which links the fragment to the activity.

I currently use the Activity's context in onCreate() in my app without issue.

Alternatively you can override onAttach and get a reference to the Activity directly and store it there:

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
}

Reference: Using context in a fragment

Answer 2

How about turning the table and letting the Wizard fragments hold the MenuItems themselves? Then they could call directly to the activity such as ((YourActivity)getActivity()).moveToNextPage().

This approach could be done for one general WizardFragment and then let all wizard pages extend from that.