将片段状态保存在导航抽屉中

Question

i am using navigation drawer in my android app..
Each of fragment contains async task which getting data from internet and displaying in custom list.

Here is code for selecting fragment:

     private void displayView(int position) {

    // update the main content by replacing fragments

    Fragment fragment = null;

    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction ft = fragmentManager.beginTransaction();
    String TAG=null;
    switch (position) {
    case 0:
        fragment = new HomeFragment();
        TAG=new String("Home");
        break;
    case 1:
        // fragment = new BlogsFragment();
        fragment = new BlogsFragment();
        break;
    case 2:

        // fragment = new NewsFragment();
        fragment = new NewsFragment();
        break;
    case 3:

        fragment = new TransferFragment();
        break;
    case 4:
        fragment = new FixturesFragment();
        break;

    case 5:

        fragment = new FeedFragment();
        break;
    case 6:

        // fragment = new TwitterFragment();
        fragment = new TwitterFragment();
        break;
    case 7:

        // fragment = new FacebookFragment();
        fragment = new FacebookFragment();
        break;
    case 8:

        // fragment = new BookmarkFragment();
        fragment = new BookmarkFragment();
        break;
    default:
        break;
    }
    if (fragment != null) {

        ft.replace(R.id.frame_container, fragment).commit();

        // update selected item and title, then close the drawer
        mDrawerList.setItemChecked(position, true);
        mDrawerList.setSelection(position);
        setTitle(navMenuTitles[position]);
        mDrawerLayout.closeDrawer(mDrawerList);

    }

    else {
        // error in creating fragment
        Log.e("MainActivity", "Error in creating fragment");
    }

}

But when i am switching between fragments an async task started loading data again..
So how to save state of fragment

I tried all the possible solution on stackoverflow

please help me

Answer 1

You can only save the state when your configuration changes or any other conditions. In your case each time you are loading the new fragment due to which it again resumes its life-cycle. Check this

Answer 2

I think you need to cache/store the server response (async task result) for every visited fragment. If its JSON you could store it as string in SharedPrefs and then just take it back from there. This also assumes some expiration time for cashed responses to refresh it.
Since you do

ft.replace(R.id.frame_container, fragment).commit();

you destroy previously shown fragment completely. You could also play with addToBackStack() instead of replace or with retainInstance state.