android - Implementing a TabListener using the Support Library

Question

I am trying to implement Tab Navigation, but I want to make sure people that have older versions of Android can still use my application.

The app in mind ATM is fairly simple, I just want to be able to understand how to implement the layout and then I'll add the missing bits.

Anyhow, I have a Container Activity that extends Fragment Activity (to ensure compatibility), and this Activity creates a TabView using an ActionBar (I believe my problem resides here). The app will try to create three tabs and add them to the ActionBar, and I want to make sure the user can scroll back and forth using lateral navigation.

Here is TabListener I am trying to implement:

public static class TabListener<T extends Fragment> implements ActionBar.TabListener {

    private Fragment mFragment;
    private final Activity mActivity;
    private final String mTag;
    private final Class<T> mClass;

    public TabListener(Activity activity, String tag, Class<T> clz) {
        mActivity = activity;
        mTag = tag;
        mClass = clz;
    }

    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        if (mFragment == null) {
            mFragment = Fragment.instantiate(mActivity, mClass.getName());
            ft.add(android.R.id.content, mFragment, mTag);
        } else {
            ft.attach(mFragment);
        }
    }

    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        if (mFragment != null) {
            ft.detach(mFragment);
        }
    }

    public void onTabReselected(Tab tab, FragmentTransaction ft) {
    }
}

Here are my imports, because I wanted to make sure I was using the support library:

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.view.Menu;

However, Eclipse is giving me issues with the TabListener methods. It is telling me the following: "The type LayoutContainer.TabListener must implement the inherited abstract method ActionBar.TabListener.onTabSelected(ActionBar.Tab, FragmentTransaction)"

When I select Add unimplemented methods Eclipse basically adds the OnTabSelected OnTabReselected and OnTabUnselected methods, but this time, passing the non-support version of the Fragment (android..app.Fragment) as a parameter.

Any ideas on how to make another implementation of lateral navigation through the support library to ensure compatibility?

Answer 1

hmmm. while Malek's works it doesn't directly answer the question..

You can simply ignore the fragment transaction you get in the callback and use your own:

android.support.v4.app.FragmentTransaction fft = mActivity.getSupportFragmentManager().beginTransaction();

Just make sure that your activity is a FragmentActivity and you'll be able to start a new fragment transaction.

Also the replace() method in the fragmentTransaction is much more convenient than add() and remove()