Passing data between Fragments in the same Activity

Question

Am working in a project with an Activity that host many fragments. Now I need to share some data (integers, strings, arraylist) between these fragments.

First time i use

Answer 1

I think the best solution for you is to have the variables inside the main activity and access them from fragments. I mean, if you have to do THE SAME in all fragments, you can write the code inside the activity and just call the method you need.

You need to use an interface for this purpose

public interface DataCommunication {
    public String getMyVariableX();
    public void setMyVariableX(String x);
    public int getMyVariableY();
    public void setMyVariableY(int y);
}

Then, implement it inside your activity

public class MainActivity extends Activity implements DataCommunication {

    private String x;
    private int y;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...   
    }

    ...

    @Override
    public String getMyVariableX(){
        return x;
    }

    @Override
    public void setMyVariableX(String x){
        //do whatever or just set
        this.x = x;
    }

    @Override
    public int getMyVariableY(){
        return y;
    }

    @Override
    public void setMyVariableY(int y){
        //do whatever or just set
        this.y = y;
    }

    ...

Then, attach the activity in ALL your fragments:

public class Fragment_1 extends Fragment{

    DataCommunication mCallback;

 @Override
    public void onAttach(Context context) {
        super.onAttach(context);

        // This makes sure that the container activity has implemented
        // the callback interface. If not, it throws an exception
        try {
            mCallback = (DataCommunication) context;
        } catch (ClassCastException e) {
            throw new ClassCastException(context.toString()
                    + " must implement DataCommunication");
        }
    }

    ...

And finally, when you need to use a variable inside a fragment, just use get and se methods you've created

https://developer.android.com/training/basics/fragments/communicating.html