Activity.onServiceConnected之前的片段重新创建给了我NPE

Question

One of my fragments have a listview that gets his adapter from my service at beggining of the fragment lifecycle. On normal lifecycle it goes without problems, but when i rotate the device, the fragment that was showing is recreated even before activity recreation, thus my service instance on activity is not ready, it is only ready after onServiceConnected(). Even if i try to recover and set this adapter in fragment.onResume(), there are no guarantees the service is already binded. In my code, i handle to add the fragments after orientation change (after onServiceConnected()) but the fragment lifecycle dont respects this order. Why the fragment is recreated before activity?

What should i do?

Activity:

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_layout);

    actionBar = getSupportActionBar();
    drawerlayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawerlayout.setDrawerShadow(R.drawable.drawer_shadow,
            GravityCompat.END);

    Intent it = new Intent(this, MyService.class);

    if (!MyService.RUNNING) {

        startService(it);
    }

    bindService(it, this, 0);

}

@Override
public void onServiceConnected(ComponentName name, IBinder binderservice) {
    Crashlytics.log(Log.INFO, TAG_ACTIVITY_LIFECYCLE,
            "Activity onServiceConnected");
    LocalBinder binder = (LocalBinder) binderservice;
    this.service = binder.getService();

    //load a fragment with a radio player
    carregaRadio(); 

    if (!service.isIRCConnected()) {

    // load a fragment to login on a chat
        carregaLogin();

    } else {

   // load fragments according to the chat
   // variables on the service when service was already
   // running before activity creation.

   carregaChatdoService(); 


    }

    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

}

Answer 1

Fragment instances are kept or saved even if the activity is destroyed. This is how I solved a similar problem by adding a OnGlobalLayoutListener in my activity onCreate . Your problem might be a little different so you could bind the service in onGlobalLayout and when onServiceConnected is called, your fragments should be ready to use.

viewPager.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {

            Log.d("Activity", "onGlobalLayout");

            if ( musicService != null)
                tabPagerAdapter.getPlaylistFragment().loadPlaylist(musicService.getPlaylist());

            viewPager.getViewTreeObserver().removeOnGlobalLayoutListener(this);
        }
    } );