Pass arraylist with bundle

Question

I have a class like this

class Message implements Serializable
{
    public String message, sender;
    public Message (String msg, String from)
    {
        // check here that msg and from are not null. If so, use a default value or throw an NullPointerException
        message = msg;
        sender = from;
    }
    // Just a utility method for printing out the Message to System.out
    public String toString () { return sender+":"+message; }
}

I am defining this variable in main activity

Hashtable<String, ArrayList<Message>> table = new Hashtable<String, ArrayList<Message>>();
table.get(room_name).add(new Message("Hi", "Sender"));
Bundle bundle = new Bundle();
bundle.putSerializable("messages", table.get(sendTo));

And in fragment I am getting this data with this code

ArrayList<Message> extractedMessages = (ArrayList<Message>)getArguments().getSerializable("messages");
System.out.println(extractedMessages.size());

But my app is crashing,I am getting java nullpointer exception for extractedMessages.size()

How can I fix this ?

Community · Accepted Answer · 2017-05-23 10:26:17Z

2

Solution is ::

Bundle.putParcelable/Bundle.getParcelable

Have a look at this answer.

Use those methods, putParcelable and getParcelable.

Also you can ::

Intent intent = new Intent(context, SecondActity.class);
intent.putIntegerArrayListExtra("arraylist",myArrayList);  //myArrayList is ArrayList<Integer>
startActivity(intent);

To get the arrayList in second Activity.

ArrayList arrayList<Integer> = getIntent().getIntegerArrayListExtra("myArrayList")

{Edit} ---- You can use newInstance to pass the data from fragment to fragment

This is one of the way to achieve it, i use constructor to pass the data

FragmentOne.java

int myData=12;
FragmentManager manager = getActivity().getSupportFragmentManager();
Fragment frgObj=FragmentTwo.newInstance(myData);
FragmentTransaction ft = manager.beginTransaction();
ft.replace(R.id.container, frgObj,"FragmentTwo");
ft.addToBackStack(null);
ft.commit();

FragmentTwo.java

int myData;
public static FragmentTwo newInstance(int _myData){
FragmentTwo fragment = new FragmentTwo();
myData=_myData
return  fragment;
}

{EDIT-3}

I have made a project for you download it from Here

Mount in in your editor and run it .... it has bunch of other stuffs .... don't bother about it
Check how i am starting a fragment from activity ----> then onClick of button how i am starting a fragment ---> there pass the data with the constructor as i shown in edit2

ALSO REFER -- this -- StackOVERFLOW POST

edited May 23, 2017 at 10:26

CommunityBot

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answered Aug 10, 2014 at 17:32

Devrath

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9 Comments

Tolgay Toklar Over a year ago

Can you give an example ?

Tolgay Toklar Over a year ago

But this is not a activity I am using fragments.

Devrath Over a year ago

You are using fragment ? .... ok .... check my edit .... i have passed the integer similarly you can pass arraylist too ... simple !

Devrath Over a year ago

@Tolgay Toklar .... download the project from my edit3 and learn how to use newInstance .... let me know if you are able to resolve it !

Tolgay Toklar Over a year ago

I think I can't do it.Is there another way to pass custom arraylist ?

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Pass arraylist with bundle

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{Edit} ---- You can use newInstance to pass the data from fragment to fragment

{EDIT-3}

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Collectives™ on Stack Overflow

1 Answer 1

{Edit} ---- You can use newInstance to pass the data from fragment to fragment

{EDIT-3}

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