Array List of objects via intent

Question

I know you can pass in an array list of String via intent, but what if it's an array list of some object that I defined? Say an array list of Bicyles, how do I do this?

Answer 1

You can make your objects implement Parcelable and use putParcelableArrayListExtra. Alternatively, you can serialize your objects in some way and put the byte array of your serialized objects.

Answer 2

This is an example. MainActivity sends list of persons to OtherActivity via Intent.

class Person implements Serializable {
    int id;
    String name;

    Person(int i, String s) {
        id = i;
        name = s;
    }
}

public class TestAndroidActivity extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        ArrayList<Person> list = new ArrayList<Person>();
        list.add(new Person(1, "Tom"));
        list.add(new Person(5, "John"));

        Intent intent = new Intent(this, OtherActitity.class);
        intent.putExtra("list", list);
        startActivity(intent);

OtherActivity.java

import java.util.ArrayList;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

public class OtherActitity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.other);

        Intent i = getIntent();
        ArrayList<Person> list = (ArrayList<Person>) i
                .getSerializableExtra("list");
        Toast.makeText(this, list.get(1).name, Toast.LENGTH_LONG).show();

    }
}