Saving Fragment State/Data from Fragment to Fragment

Question

I'm trying to figure out how to save user inputted data on a fragment if they leave it and come back. I have one Activity that several Fragments work off of. All the examples I find are saving the state when leaving the Fragment and Activity. I'm never leaving the Activity; therefore onSaveInstanceState within the Fragment is never called. onPause is called, but I'm unable to figure out how to save the state within there.

This app displays a list of tickets. When the user taps a ticket, it grabs preliminary information from the local DB for read only fields and allows the user to input the ticket information before submitting. I'm trying to allow a user to tap on a ticket, enter data, leave and come back to that ticket without losing information entered.

Out of all the examples I've studied on this, it seems to me I can use Fragmenttransaction to save the Fragment's ID. Below is the main Activity that all fragments are attached to:

public class Activity_Main extends Activity 
implements  Fragment_OpenTickets.INT_OnOpenTicketSelectedListener,
            Fragment_SubTickets.INT_OnSubTicketSelectedListener,
            Fragment_Ticket.INT_SubmitNewTicket {
DBController dbc;
Fragment fr;
boolean gps_enabled = false;
boolean network_enabled = false;
HashMap<String, String> addInfo;
RadioButton btn_radio_open;
RadioButton btn_radio_submitted;
RadioButton btn_radio_settings;
String ticketDate, ticketTime;
int m, d, y, hr, min;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    btn_radio_open = (RadioButton)findViewById(R.id.radio_open);
    btn_radio_submitted = (RadioButton)findViewById(R.id.radio_submitted);
    btn_radio_settings = (RadioButton)findViewById(R.id.radio_settings);
    dbc = new DBController(this);
    if (dbc.checkCredentials() != null) {
        fr = new Fragment_OpenTickets();
    } else {
        fr = new Fragment_Settings();
        btn_radio_open.setChecked(false);
        btn_radio_submitted.setChecked(false);
        btn_radio_settings.setChecked(true);
    }
    FragmentManager fm = getFragmentManager();
    final FragmentTransaction ft = fm.beginTransaction();
    ft.add(R.id.fragment_place, fr);
    ft.addToBackStack(null); // For back button action.
    ft.commit();

    // Start scheduler service.
    this.startService(new Intent(this, Service_Send.class));
    // Start GPS service.
    startGPS();
}

/**
 * Top menu buttons.
 */
public void selectFrag(View view) {
    FragmentTransaction ft = getFragmentManager().beginTransaction();
    switch (view.getId()) {
        case R.id.radio_open:
            //fr = new Fragment_OpenTickets();
            ft.replace(R.id.fragment_place, new Fragment_OpenTickets());
            ft.addToBackStack(null);
            btn_radio_submitted.setChecked(false);
            btn_radio_settings.setChecked(false);
            ft.commit();
            break;
        case R.id.radio_submitted:
            //fr = new Fragment_SubTickets();
            ft.replace(R.id.fragment_place, new Fragment_SubTickets());
            ft.addToBackStack(null);
            btn_radio_open.setChecked(false);
            btn_radio_settings.setChecked(false);
            ft.commit();
            break;
        case R.id.radio_settings:
            //fr = new Fragment_Settings();
            ft.replace(R.id.fragment_place, new Fragment_Settings());
            ft.addToBackStack(null);
            btn_radio_open.setChecked(false);
            btn_radio_submitted.setChecked(false);
            ft.commit();
            break;
    }
}

/**
 * Open ticket selection action.
 */
public void onOpenTicketSelected(HashMap position) {
    // Create fragment and give it an argument for the selected ticket.
    fr = new Fragment_Ticket();
    Bundle args = new Bundle();
    args.putSerializable("HashMap", position);
    fr.setArguments(args);

    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.add(R.id.fragment_place, fr);
    ft.addToBackStack(null); // For back button action.
    ft.commit();
}

/**
 * Submitted ticket selection action.
 */
public void onSubTicketSelected(HashMap position) {
    // Create fragment and give it an argument for the selected ticket.
    fr = new Fragment_SubTicket();
    Bundle args = new Bundle();
    args.putSerializable("HashMap", position);
    fr.setArguments(args);

    FragmentManager fm = getFragmentManager();
    FragmentTransaction fragmentTransaction = fm.beginTransaction();
    fragmentTransaction.replace(R.id.fragment_place, fr);
    fragmentTransaction.addToBackStack(null); // For back button action.
    fragmentTransaction.commit();
}

Any help will be very appreciated. If I need to post more code then please let me know. Thank you!

score 0 · Accepted Answer · answered Jul 03 '15 at 02:06

0

I think you should store ticket info in your Activity when users leave the fragment and get the info back and display it when you come back.

In Activity_Main class, you create 2 methods:

public void saveTicketInfo(TicketInfo info) {
    // save info here
}

And:

public TicketInfo getTicketInfo() {
    // get info here
}

In your fragment:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
    ...
    // get ticket info and display it
    Activity_Main mainActivity = (Activity_Main)getActivity();
    TicketInfo info = mainActivity.getTicketInfo();
    if (info != null) {
        // handle display info here
    }
    ...
}

@Override
public void onDestroyView() {
    TicketInfo info = new TicketInfo();
    // get info from view and store in the object
    Activity_Main mainActivity = (Activity_Main)getActivity();
    mainActivity.saveTicketInfo(info)
    super.onDestroyView();
}

answered Jul 03 '15 at 02:06

Thanh Pham

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Thank you, Thanh. This is starting to give me the desired behavior. The issue I see now is if they select a different ticket from the last one it thinks it has that data stored and would populate the newly selected ticket with the wrong data. This is why I know I have to some how use unique ID's. All the tickets use the same Fragment, just with different data. – Chris C. Jul 03 '15 at 05:30
@Chris C., The posted answer is reasonable but problems may arise when a user hits the Back key, for one example, and the activity may not be accessible, and about to be destroyed. Read Google webpage @ http://developer.android.com/guide/components/fragments.html . There is a paragraph saying "...However, be careful to call getActivity() only when the fragment is attached to an activity..." – The Original Android Jul 03 '15 at 07:15
Yes, this answer is reasonable. Being able to save the inputted data on each ticket is a little more in depth. Thank you again everybody! – Chris C. Jul 03 '15 at 16:45

score 0 · Answer 2 · edited May 23 '17 at 11:51

0

I posted a lengthy detailed answer on SO @ Passing data between fragments contained in an activity. Search for my answer on it. This is a safe way to pass data from Fragment to Activity. And then you can easily pass that data from Activity to the Fragment's constructor or public method.

edited May 23 '17 at 11:51

Community

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1

answered Jul 03 '15 at 07:22

The Original Android

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Saving Fragment State/Data from Fragment to Fragment

2 Answers2