Getting back object from child activiy in Android

Question

I have a main_activity that starts a child Activity via Intent.

I know about methods getStringExtra(string), or getBooleanExtra(string) etc. that we call in onActivityResult; But they all return a primitive data... How can I get an object from a user-defined class from the child activity?

Thanks, and this is my first question here! :) kinda too late...

xyz · Answer 1 · 2015-07-13T04:39:14.057

You're looking for Parcelable.

A simpler, though non optimal solution is Serializable.

Snippet:

 public class MyParcelable implements Parcelable {
     private int mData;

     public int describeContents() {
         return 0;
     }

     public void writeToParcel(Parcel out, int flags) {
         out.writeInt(mData);
     }

     public static final Parcelable.Creator<MyParcelable> CREATOR
             = new Parcelable.Creator<MyParcelable>() {
         public MyParcelable createFromParcel(Parcel in) {
             return new MyParcelable(in);
         }

         public MyParcelable[] newArray(int size) {
             return new MyParcelable[size];
         }
     };

     private MyParcelable(Parcel in) {
         mData = in.readInt();
     }
 }

Usage:

// Sender class
MyParcelable mp = new MyParcelable();
intent.putExtra("KEY_PARCEL", mp);

// Receiver class
Bundle data = getIntent().getExtras();
MyParcelable student = (Myparcelable)data.getParcelable("KEY_PARCEL");

Here's a working example.

EDIT: Here's how to do it with fragments.

// Receiver class
Bundle data = getIntent().getExtras();

public class MyFragment extends Fragment {

    public static MyFragment newInstance(int index, Bundle data) {
        MyFragment f = new MyFragment();
        data.putInt("index", index);
        f.setArguments(data);
        return f;
    }

}

// In the fragment
Bundle data = getArguments();

Just to make it clear for noobs like me, it should be getActivity().getIntent().getExtras() if used in fragments! — sorry_I_wont, Jul 13 '15 at 00:14
@Ashl7 that would work, but not a good design practice. I updated my answer. — xyz, Jul 13 '15 at 04:40

score 1 · Accepted Answer · answered Jun 28 '15 at 06:01

You can create Parcelable custom object.

like this

public class Student implements Parcelable{

add to intent like this

intent.putExtra("student", obj);

Then get That object like

Bundle data = getIntent().getExtras();
Student student = (Student) data.getParcelable("student");

score 0 · Answer 3 · answered Jul 12 '15 at 20:13

0

There is this website that makes Parselabel classes out of your custom class....swweeeeeet! http://www.parcelabler.com/

answered Jul 12 '15 at 20:13

sorry_I_wont

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Getting back object from child activiy in Android

3 Answers3