Passing an Object from an Activity to a Fragment

I have an Activity which uses a Fragment. I simply want to pass an object from this Activity to the Fragment.

How could I do it? All the tutorials I've seen so far where retrieving data from resources.

EDIT :

Let's be a bit more precise:

My Activity has a ListView on the left part. When you click on it, the idea is to load a Fragment on the right part.

When I enter this Activity, an Object Category is given through the Intent. This Object contains a List of other Objects Questions (which contains a List of String). These Questions objects are displayed on the ListView. When I click on one item from the ListView, I want to display the List of String into the Fragment (into a ListView).

To do that, I call the setContentView() from my Activity with a layout. In this layout is defined the Fragment with the correct class to call. When I call this setContentView(), the onCreateView() of my Fragment is called but at this time, the getArguments() returns null.

How could I manage to have it filled before the call of onCreateView() ? (tell me if I'm not clear enough)

Thanks

Create a static method in the Fragment and then get it using getArguments().

Example:

public class CommentsFragment extends Fragment {
  private static final String DESCRIBABLE_KEY = "describable_key";
  private Describable mDescribable;

  public static CommentsFragment newInstance(Describable describable) {
    CommentsFragment fragment = new CommentsFragment();
    Bundle bundle = new Bundle();
    bundle.putSerializable(DESCRIBABLE_KEY, describable);
    fragment.setArguments(bundle);

    return fragment;
  }

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

    mDescribable = (Describable) getArguments().getSerializable(
        DESCRIBABLE_KEY);

    // The rest of your code
}

You can afterwards call it from the Activity doing something like:

FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
Fragment fragment = CommentsFragment.newInstance(mDescribable);
ft.replace(R.id.comments_fragment, fragment);
ft.commit();

In your activity class:

public class BasicActivity extends Activity {

private ComplexObject co;

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

	co=new ComplexObject();
	getIntent().putExtra("complexObject", co);

	FragmentManager fragmentManager = getFragmentManager();
	Fragment1 f1 = new Fragment1();
	fragmentManager.beginTransaction()
			.replace(R.id.frameLayout, f1).commit();

}

Note: Your object should implement Serializable interface

Then in your fragment :

public class Fragment1 extends Fragment {

ComplexObject co;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
		Bundle savedInstanceState) {
	Intent i = getActivity().getIntent();
	
	co = (ComplexObject) i.getSerializableExtra("complexObject");

	View view = inflater.inflate(R.layout.test_page, container, false);
	TextView textView = (TextView) view.findViewById(R.id.DENEME);
	textView.setText(co.getName());

	return view;
}
}

You should create a method within your fragment that accepts the type of object you wish to pass into it. In this case i named it "setObject" (creative huh? :) ) That method can then perform whatever action you need with that object.

MyFragment fragment;

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

        if (getSupportFragmentManager().findFragmentById(android.R.id.content) == null) {
            fragment = new MyFragment();
            getSupportFragmentManager().beginTransaction().add(android.R.id.content, detailsFragment)
                    .commit();
        } else {
           fragment = (MyFragment) getSupportFragmentManager().findFragmentById(
                    android.R.id.content);
        }


        fragment.setObject(yourObject); //create a method like this in your class "MyFragment"
}

Note that i'm using the support library and calls to getSupportFragmentManager() might be just getFragmentManager() for you depending on what you're working with

Passing arguments by bundle is restricted to some data types. But you can transfer any data to your fragment this way:

In your fragment create a public method like this

public void passData(Context context, List<LexItem> list, int pos) {
    mContext = context;
    mLexItemList = list;
    mIndex = pos;
}

and in your activity call passData() with all your needed data types after instantiating the fragment

        WebViewFragment myFragment = new WebViewFragment();
        myFragment.passData(getApplicationContext(), mLexItemList, index);
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();
        ft.add(R.id.my_fragment_container, myFragment);
        ft.addToBackStack(null);
        ft.commit();

Remark: My fragment extends "android.support.v4.app.Fragment", therefore I have to use "getSupportFragmentManager()". Of course, this principle will work also with a fragment class extending "Fragment", but then you have to use "getFragmentManager()".

Get reference from the following example.

1. In fragment: Create a reference variable for the class whose object you want in the fragment. Simply create a setter method for the reference variable and call the setter before replacing fragment from the activity.

 MyEmployee myEmp;
 public void setEmployee(MyEmployee myEmp)
 {
     this.myEmp = myEmp;
 }

2. In activity:

   //we need to pass object myEmp to fragment myFragment

    MyEmployee myEmp = new MyEmployee();
    
    MyFragment myFragment = new MyFragment();
    
    myFragment.setEmployee(myEmp);
    
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.main_layout, myFragment);
    ft.commit();

To pass an object to a fragment, do the following:

First store the objects in Bundle, don't forget to put implements serializable in class.

            CategoryRowFragment fragment = new CategoryRowFragment();

            // pass arguments to fragment
            Bundle bundle = new Bundle();

            // event list we want to populate
            bundle.putSerializable("eventsList", eventsList);

            // the description of the row
            bundle.putSerializable("categoryRow", categoryRow);

            fragment.setArguments(bundle);
            

Then retrieve bundles in Fragment

       // events that will be populated in this row
        mEventsList = (ArrayList<Event>)getArguments().getSerializable("eventsList");

        // description of events to be populated in this row
        mCategoryRow = (CategoryRow)getArguments().getSerializable("categoryRow");

If the data should survive throughout the application lifecycle and shared among multiple fragments or activities, a Model class might come into consideration, which has got less serialization overhead.

Check this design example

This one worked for me:

In Activity:

User user;
public User getUser(){ return this.user;}

In Fragment's onCreateView method:

User user = ((MainActivity)getActivity()).getUser(); 

Replace the MainActivity with your Activity Name.