How to pass an object from one activity to another on Android

I am trying to work on sending an object of my customer class from one Activity and display it in another Activity.

The code for the customer class:

public class Customer {

    private String firstName, lastName, Address;
    int Age;

    public Customer(String fname, String lname, int age, String address) {

        firstName = fname;
        lastName = lname;
        Age = age;
        Address = address;
    }

    public String printValues() {

        String data = null;

        data = "First Name :" + firstName + " Last Name :" + lastName
        + " Age : " + Age + " Address : " + Address;

        return data;
    }
}

I want to send its object from one Activity to another and then display the data on the other Activity.

How can I achieve that?

Solution 1:

One option could be letting your custom class implement the Serializable interface and then you can pass object instances in the intent extra using the putExtra(Serializable..) variant of the Intent#putExtra() method.

Pseudocode:

//To pass:
intent.putExtra("MyClass", obj);

// To retrieve object in second Activity
getIntent().getSerializableExtra("MyClass");

Note: Make sure each nested class of your main custom class has implemented Serializable interface to avoid any serialization exceptions. For example:

class MainClass implements Serializable {

    public MainClass() {}

    public static class ChildClass implements Serializable {

        public ChildClass() {}
    }
}

Solution 2:

Implement your class with Serializable. Let's suppose that this is your entity class:

import java.io.Serializable;

@SuppressWarnings("serial") //With this annotation we are going to hide compiler warnings
public class Deneme implements Serializable {

    public Deneme(double id, String name) {
        this.id = id;
        this.name = name;
    }

    public double getId() {
        return id;
    }

    public void setId(double id) {
        this.id = id;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    private double id;
    private String name;
}

We are sending the object called dene from X activity to Y activity. Somewhere in X activity;

Deneme dene = new Deneme(4,"Mustafa");
Intent i = new Intent(this, Y.class);
i.putExtra("sampleObject", dene);
startActivity(i);

In Y activity we are getting the object.

Intent i = getIntent();
Deneme dene = (Deneme)i.getSerializableExtra("sampleObject");

That's it.

Solution 3:

Use gson to convert your object to JSON and pass it through intent. In the new Activity convert the JSON to an object.

In your build.gradle, add this to your dependencies

implementation 'com.google.code.gson:gson:2.8.4'

In your Activity, convert the object to json-string:

Gson gson = new Gson();
String myJson = gson.toJson(vp);
intent.putExtra("myjson", myjson);

In your receiving Activity, convert the json-string back to the original object:

Gson gson = new Gson();
YourObject ob = gson.fromJson(getIntent().getStringExtra("myjson"), YourObject.class);

For Kotlin it's quite the same

Pass the data

val gson = Gson()
val intent = Intent(this, YourActivity::class.java)
intent.putExtra("identifier", gson.toJson(your_object))
startActivity(intent)

Receive the data

val gson = Gson()
val yourObject = gson.fromJson<YourObject>(intent.getStringExtra("identifier"), YourObject::class.java)

Solution 4:

• Using global static variables is not good software engineering practice.
• Converting an object's fields into primitive data types can be a hectic job.
• Using serializable is OK, but it's not performance-efficient on the Android platform.
• Parcelable is specifically designed for Android and you should use it. Here is a simple example: Passing custom objects between Android activities

You can generate Parcelable code for you class using this site.