getArguments return null

Question

I need to transfer arraylist from one fragment to another. I looked at a few articles with the same problem, but not one of the options could not solve my problem....
From BakeFragment

OrderFragment orderFragment = new OrderFragment();
                   Bundle bundle = new Bundle();
                   bundle.putStringArrayList(ORDER_KEY, orderList);
                    orderFragment.setArguments(bundle);

I need to get this arraylist in OrderFragment. How i try to do it

First version

Bundle mBundle = this.getArguments();
orderArrayList = mBundle.getStringArrayList(ORDER_KEY);

Error :

java.lang.NullPointerException
        at com.zhisheng.navdrawer.model.OrderFragment.onCreateView(OrderFragment.java:38)
        at android.app.Fragment.performCreateView(Fragment.java:1699)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:885)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1057)
        at android.app.BackStackRecord.run(BackStackRecord.java:682)
        at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435)
        at android.app.FragmentManagerImpl$1.run(FragmentManager.java:441)
        at android.os.Handler.handleCallback(Handler.java:730)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5137)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:756)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:572)
        at miui.dexspy.DexspyInstaller.main(DexspyInstaller.java:171)
        at dalvik.system.NativeStart.main(Native Method)

Second version

if(getArguments()!=null){
        orderArrayList = this.getArguments().getStringArrayList("key");
    }

Don't get an error, but nothing happens.

public class MainActivity extends AppCompatActivity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;

// nav drawer title
private CharSequence mDrawerTitle;

// used to store app title
private CharSequence mTitle;

// slide menu items
private String[] navMenuTitles;
private TypedArray navMenuIcons;

private ArrayList<NavDrawerItem> navDrawerItems;
private NavDrawerListAdapter adapter;

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

    mTitle = mDrawerTitle = getTitle();

    // load slide menu items
    navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);

    // nav drawer icons from resources
    navMenuIcons = getResources()
            .obtainTypedArray(R.array.nav_drawer_icons);

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    mDrawerList = (ListView) findViewById(R.id.list_slidermenu);

    navDrawerItems = new ArrayList<NavDrawerItem>();



    // adding nav drawer items to array
    // Home
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
    // Find People
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
    // Photos
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
    // Communities, Will add a counter here
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));
    // Pages
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
    // What's hot, We  will add a counter here
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[6], navMenuIcons.getResourceId(6, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[7], navMenuIcons.getResourceId(7, -1)));
    // Find People
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[8], navMenuIcons.getResourceId(8, -1)));
    // Photos
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[9], navMenuIcons.getResourceId(9, -1)));
    // Communities, Will add a counter here
    navDrawerItems.add(new NavDrawerItem(navMenuTitles[10], navMenuIcons.getResourceId(10, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[11], navMenuIcons.getResourceId(11, -1)));


    // Recycle the typed array
    navMenuIcons.recycle();

    mDrawerList.setOnItemClickListener(new SlideMenuClickListener());

    // setting the nav drawer list adapter
    adapter = new NavDrawerListAdapter(getApplicationContext(),
            navDrawerItems);
    mDrawerList.setAdapter(adapter);

    // enabling action bar app icon and behaving it as toggle button
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setHomeButtonEnabled(true);

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.string.navigation_drawer_open, R.string.navigation_drawer_close) {
        public void onDrawerClosed(View view) {
            getSupportActionBar().setTitle(mTitle);
            // calling onPrepareOptionsMenu() to show action bar icons
            invalidateOptionsMenu();

        }

        public void onDrawerOpened(View drawerView) {
            getSupportActionBar().setTitle(mDrawerTitle);
            // calling onPrepareOptionsMenu() to hide action bar icons
            invalidateOptionsMenu();
        }
    };
    mDrawerLayout.setDrawerListener(mDrawerToggle);

    if (savedInstanceState == null) {


        displayView(11);
    }

}

/**
 * Slide menu item click listener
 */
private class SlideMenuClickListener implements
        ListView.OnItemClickListener {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
                            long id) {
        // display view for selected nav drawer item
        displayView(position);
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // toggle nav drawer on selecting action bar app icon/title
    if (mDrawerToggle.onOptionsItemSelected(item)) {
        return true;
    }
    // Handle action bar actions click
    switch (item.getItemId()) {
        case R.id.action_settings:
          return true;
        default:
          displayView(11);

            //Toast.makeText(getApplicationContext(), "RasRas", Toast.LENGTH_LONG).show();
            return true;
    }
}

/* *
 * Called when invalidateOptionsMenu() is triggered
 */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
    // if nav drawer is opened, hide the action items
    boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
    menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
    return super.onPrepareOptionsMenu(menu);
}

/**
 * Diplaying fragment view for selected nav drawer list item
 */
private void displayView(int position) {
    // update the main content by replacing fragments
    Fragment fragment = null;
    switch (position) {
        case 0:
            fragment = new BakeFragment();
            break;
        case 1:
            fragment = new GarnishFragment();
            break;
        case 2:
            fragment = new HotDishesFragment();
            break;
        case 3:
            fragment = new DesertsFragment();
            break;
        case 4:
            fragment = new HomeFragment();
            break;
        case 5:
            fragment = new SnacksFragment();
            break;
        case 6:
            fragment = new DrinkFragment();
            break;
        case 7:
            fragment = new PizzaFragment();
            break;
        case 8:
            fragment = new SaladFragment();
            break;
        case 9:
            fragment = new ConfectionFragment();
            break;
        case 10:
            fragment = new SoupFragment();
            break;
        case 11:
            fragment = new OrderFragment();
        default:
            break;
    }

    if (fragment != null) {
        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction()
                .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");
    }
}

@Override
public void setTitle(CharSequence title) {
    mTitle = title;
    getSupportActionBar().setTitle(mTitle);
}

/**
 * When using the ActionBarDrawerToggle, you must call it during
 * onPostCreate() and onConfigurationChanged()...
 */

@Override
protected void onPostCreate(Bundle savedInstanceState) {
    super.onPostCreate(savedInstanceState);
    // Sync the toggle state after onRestoreInstanceState has occurred.
    mDrawerToggle.syncState();
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    // Pass any configuration change to the drawer toggls
    mDrawerToggle.onConfigurationChanged(newConfig);
}

BakeFragment

public class BakeFragment extends Fragment {

final static String ORDER_KEY="key";

String myString;

ListView listView;
ArrayList<MenuItem> arrayList;
CustomAdapter customAdapter;
MenuItem menuItem;

ArrayList<String>  orderList;

View rootView = null;


Integer[] quantity = {
  1, 2, 3, 4, 5, 6, 7, 8, 9, 10
};

String[] bakeList = new String[]{
        "Булочка с кунжутом", "Ватрушка с творогом", "Качори с чечевицей", "Лепешка \"Пападам\"",
        "Лепешка \"Паратха\"", "Лепешка \"Чапати\"", "Лепешка с сыром", "Пирожное \"Корзиночка\"",
        "Пирожок с капустой", "Пирожок с картофелем", "Пряник кокосовый экадашный" , "Самоса с вишней",
        "Самоса с клубникой", "Самоса с малиной","Самоса с овощами и паниром", "Самоса с сухофруктами (печеная)",  "Самоса с творогом", "Самоса с черной смородиной",
        "Самоса с яблоком в карамели"
};


Integer[] imagesOfBakeList = new Integer[]{
        R.drawable.bake1, R.drawable.bake2, R.drawable.bake3, R.drawable.bake4, R.drawable.bake5,
        R.drawable.bake6, R.drawable.bake7, R.drawable.bake8, R.drawable.bake9, R.drawable.bake10,
        R.drawable.bake11, R.drawable.bake12, R.drawable.bake13, R.drawable.bake14, R.drawable.bake15,
        R.drawable.bake16, R.drawable.bake17, R.drawable.bake18, R.drawable.bake19


};

String[] priceOfBakeList = new String[]{
        "30", "60", "60", "30", "70", "30", "70", "90", "60", "60", "60", "60", "60", "60", "60", "60",
        "60", "60", "60"
};



@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

     rootView = inflater.inflate(R.layout.list_item, container, false);

    listView = (ListView)rootView.findViewById(R.id.list_of_menu_item);
    orderList = new ArrayList<String>();
    arrayList = new ArrayList<MenuItem>();
    for(int i = 0; i < bakeList.length; i++) {
        menuItem = new MenuItem(imagesOfBakeList[i], bakeList[i], priceOfBakeList[i]);
        arrayList.add(menuItem);
    }
    customAdapter = new CustomAdapter(getActivity().getApplicationContext(), arrayList);
    listView.setAdapter(customAdapter);

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        View v = null;


        @Override
        public void onItemClick(AdapterView<?> parent, final View view, int position, long id) {
            //Toast.makeText(getActivity().getApplicationContext(), "Вы заказали " + customAdapter.getItem(position), Toast.LENGTH_SHORT).show();
            LayoutInflater layoutInflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            v = layoutInflater.inflate(R.layout.view, null);
            String dishForOrderList;
            final int s = customAdapter.getPrice(position);
            final String dish = customAdapter.getItem(position).toString();
            final String allstr;
            Spinner spinner = (Spinner) v.findViewById(R.id.spinView);
            final TextView orderText = (TextView) v.findViewById(R.id.order_text);
            ArrayAdapter<CharSequence> spinnerAdapter = ArrayAdapter.createFromResource(getActivity(), R.array.option, android.R.layout.simple_spinner_item);
            spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            spinner.setAdapter(spinnerAdapter);
            spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                @Override
                public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                    String selected = parent.getSelectedItem().toString();
                    int t = Integer.parseInt(selected);
                    myString = dish + " x" + t + "     " + (s * t);
                    String abc = dish+" x"+t+"     !";
                    orderText.setText(myString);
                     Toast.makeText(getActivity(), myString, Toast.LENGTH_LONG).show();

                }

                @Override
                public void onNothingSelected(AdapterView<?> parent) {

                }
            });

            AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());


            builder.setView(v);
            builder.setTitle("Сколько порций " + dish + " вы хотите заказать?");
            builder.setCancelable(false);

            builder.setNegativeButton("Заказать", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {

                    orderList.add(myString);

                  Toast.makeText(getActivity(), orderList+"", Toast.LENGTH_LONG).show();
                   OrderFragment orderFragment = new OrderFragment();
                   Bundle bundle = new Bundle();
                   bundle.putStringArrayList(ORDER_KEY, orderList);
                    orderFragment.setArguments(bundle);
                    dialog.cancel();
                }
            });
            builder.setPositiveButton("Отмена", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            });
            AlertDialog alertDialog = builder.create();
            alertDialog.show();

        }
    });

    return rootView;

}

}

OrderFragment

public class OrderFragment extends Fragment {

View rootView = null;
ListView orderListView;
ArrayList<String> orderArrayList;
ArrayAdapter<String> stringArrayAdapter;

final static String ORDER_KEY="key";


@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    rootView = inflater.inflate(R.layout.order_list, container, false);
    orderArrayList = new ArrayList<String>();

   Bundle mBundle = this.getArguments();
   orderArrayList = mBundle.getStringArrayList(ORDER_KEY);

 /*   if(getArguments()!=null){
        orderArrayList = this.getArguments().getStringArrayList("key");
    }*/
   // orderArrayList = this.getArguments()!=null? getArguments().getStringArrayList("array") : null;
    //Toast.makeText(getActivity(), "d = "+orderArrayList, Toast.LENGTH_LONG).show();
//        orderArrayList = bundle.getStringArrayList("key");
  orderListView = (ListView)rootView.findViewById(R.id.order_list_view);
    stringArrayAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, orderArrayList);
    orderListView.setAdapter(stringArrayAdapter);

    return rootView;
}}

Answer 1

I think your problem can be traced to this block of code:

public void onClick(DialogInterface dialog, int which) {

    orderList.add(myString);

    Toast.makeText(getActivity(), orderList+"", Toast.LENGTH_LONG).show();
    OrderFragment orderFragment = new OrderFragment();
    Bundle bundle = new Bundle();
    bundle.putStringArrayList(ORDER_KEY, orderList);
    orderFragment.setArguments(bundle);
    dialog.cancel();
}

You are trying to create an OrderFragment as a result of the dialog button being clicked. However, since you are not attaching this instance to the activity, the arguments are never set. In the displayView() method you have this:

case 11:
    fragment = new OrderFragment();

Basically, the fragment that you have doesn't have any arguments set - this is why you can't see them afterwards.

To deal with this, I can suggest you take a couple of steps:

1. Implement a proper fragment - fragment communication. Bear in mind that fragments should never communicate directly to one another (except if they are nested, but this is not your case). It would be better if you organize this through the activity - BakeFragment gets the orders, sends them to the activity and the activity sets them as arguments of the OrderFragment. You can get a nice example and more info on this approach here: http://developer.android.com/training/basics/fragments/communicating.html

2. Reorganize your displayView() method. Currently, you are going to force the creation of a new instance of the desired fragment each time you invoke this method. This can lead to undesired behavior - poor performance, strange state of the back stack, etc. Further more, you won't be able to benefit from the automatic saving of fragment parameters when fragments get recreated. I suggest you make use of tags and firstly check if the fragment, you want to show, is already there.

   FragmentManager fm = getSupportFragmentManager();
   Fragment fragment = fm.findByTag(THE_FRAGMENT_TAG);
   if (fragment == null) {
       // logic to create a fragment instance
   } 
   // logic to show the fragment
   

Answer 2

The only time I see your OrderFragment used in a FragmentTransaction is when it is created in your MainActivity displayView method. There, it has no arguments set on it.

Your BakeFragment does create an OrderFragment and set its arguments, but it is never added through a FragmentTransaction and goes out of scope as soon as your onClick(DialogInterface dialog, int which) method is done executing. Therefore the OrderFragment with arguments set is never used.

Did you mean to show this fragment to the user through the use of a FragmentTransaction? If so, you could have BakeFragment define an interface with a method that indicates to the listener that the user either decided to create an order or cancelled. Have MainActivity implement this interface and register itself as a listener on your BakeFragment.

PS: Why is your logic seemingly reversed with your AlertDialog negative and positive button click handlers?