How to send an object from one Android Activity to another using Intents?

Question

How can I pass an object of a custom type from one Activity to another using the putExtra() method of the class Intent?

Answer 1

I use Gson with its so powerful and simple api to send objects between activities,

Example

// This is the object to be sent, can be any object
public class AndroidPacket {

    public String CustomerName;

   //constructor
   public AndroidPacket(String cName){
       CustomerName = cName;
   }   
   // other fields ....


    // You can add those functions as LiveTemplate !
    public String toJson() {
        Gson gson = new Gson();
        return gson.toJson(this);
    }

    public static AndroidPacket fromJson(String json) {
        Gson gson = new Gson();
        return gson.fromJson(json, AndroidPacket.class);
    }
}

2 functions you add them to the objects that you want to send

Usage

Send Object From A to B

    // Convert the object to string using Gson
    AndroidPacket androidPacket = new AndroidPacket("Ahmad");
    String objAsJson = androidPacket.toJson();

    Intent intent = new Intent(A.this, B.class);
    intent.putExtra("my_obj", objAsJson);
    startActivity(intent);

Receive In B

@Override
protected void onCreate(Bundle savedInstanceState) {        
    Bundle bundle = getIntent().getExtras();
    String objAsJson = bundle.getString("my_obj");
    AndroidPacket androidPacket = AndroidPacket.fromJson(objAsJson);

    // Here you can use your Object
    Log.d("Gson", androidPacket.CustomerName);
}

I use it almost in every project i do and I have no performance issues.

Answer 2

I struggled with the same problem. I solved it by using a static class, storing any data I want in a HashMap. On top I use an extension of the standard Activity class where I have overriden the methods onCreate an onDestroy to do the data transport and data clearing hidden. Some ridiculous settings have to be changed e.g. orientation-handling.

Annotation: Not providing general objects to be passed to another Activity is pain in the ass. It's like shooting oneself in the knee and hoping to win a 100 metres. "Parcable" is not a sufficient substitute. It makes me laugh... I don't want to implement this interface to my technology-free API, as less I want to introduce a new Layer... How could it be, that we are in mobile programming so far away from modern paradigm...

Answer 3

in your class model (Object) implement Serializable, for Example:

public class MensajesProveedor implements Serializable {

    private int idProveedor;


    public MensajesProveedor() {
    }

    public int getIdProveedor() {
        return idProveedor;
    }

    public void setIdProveedor(int idProveedor) {
        this.idProveedor = idProveedor;
    }


}

and your first Activity

MensajeProveedor mp = new MensajeProveedor();
Intent i = new Intent(getApplicationContext(), NewActivity.class);
                i.putExtra("mensajes",mp);
                startActivity(i);

and your second Activity (NewActivity)

        MensajesProveedor  mensajes = (MensajesProveedor)getIntent().getExtras().getSerializable("mensajes");

good luck!!

Answer 4

By far the easiest way IMHO to parcel objects. You just add an annotation tag above the object you wish to make parcelable.

An example from the library is below https://github.com/johncarl81/parceler

@Parcel
public class Example {
    String name;
    int age;

    public Example(){ /*Required empty bean constructor*/ }

    public Example(int age, String name) {
        this.age = age;
        this.name = name;
    }

    public String getName() { return name; }

    public int getAge() { return age; }
}

Answer 5

you can use putExtra(Serializable..) and getSerializableExtra() methods to pass and retrieve objects of your class type; you will have to mark your class Serializable and make sure that all your member variables are serializable too...

Answer 6

You can use android BUNDLE to do this.

Create a Bundle from your class like:

public Bundle toBundle() {
    Bundle b = new Bundle();
    b.putString("SomeKey", "SomeValue");

    return b;
}

Then pass this bundle with INTENT. Now you can recreate your class object by passing bundle like

public CustomClass(Context _context, Bundle b) {
    context = _context;
    classMember = b.getString("SomeKey");
}

Declare this in your Custom class and use.