Help passing an ArrayList of Objects to a new Activity

Question

I have an arraylist of objects. ie ArrayList.

I want to pass this to a new Activity. I tried to use putParcelableArrayList but it has issues with the object. I remov

Answer 1

You have two options:

• Objects in the ArrayList put implement Parceable as required by the method putParcelableArrayList ()

• Or the objects can implement Serializable and use the method putSerializable() to add the ArrayList, ie bundle.putSerializable("arraylist", arraylist);

Android passes Object in Bundle by serializing and deserializing (via Serializable or Parcelable). So all of your Objects you want to pass in a Bundle must implement one of those two interfaces.

Most Object serialize easily with Serializable and it is much simpler to implement Serializable and add a static UID to the class than to write all the methods/classes required for Parcelable.

Answer 2

Your object class should implement parcelable. The code below should get you started.

    public class ObjectName implements Parcelable {

    // Your existing code

        public ObjectName(Parcel in) {
            super(); 
            readFromParcel(in);
        }

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

            public ObjectName[] newArray(int size) {

                return new ObjectName[size];
            }

        };

        public void readFromParcel(Parcel in) {
          Value1 = in.readInt();
          Value2 = in.readInt();
          Value3 = in.readInt();

        }
        public int describeContents() {
            return 0;
        }

        public void writeToParcel(Parcel dest, int flags) {
            dest.writeInt(Value1);
            dest.writeInt(Value2);  
            dest.writeInt(Value3);
       }
    }

To use the above do this:

In 'sending' activity use:

ArrayList<ObjectName> arraylist = new Arraylist<ObjectName>();  
Bundle bundle = new Bundle();  
bundle.putParcelableArrayList("arraylist", arraylist);

In 'receiving' activity use:

Bundle extras = getIntent().getExtras();  
ArrayList<ObjectName> arraylist  = extras.getParcelableArrayList("arraylist");  
ObjectName object1 = arrayList[0];

and so on.

Answer 3

You can use a public static field in some of your classes.

See here for more advices.

Answer 4

You can pass your arraylist using Serializable interface. (Serialization is the process of converting an object into a stream of bytes in order to store the object or transmit it to memory, a database, or a file.)

public class ObjectName implements Serializable{
    private int Value1;
    private int Value2;
    private int Value3;

    public ObjectName (int pValue1, int pValue2, int Value3) {
        Value1 = pValue1;
        Value2 = pValue2;
        Value3 = pValue3;
    }

    // Get Statements for each value below
    public int getValue1() {
        return Value1;
    } 
    // etc
}

Now in your current activity

// here is the arrayList of yours
ArrayList<ObjectName> objNamesList = new ArrayList<>();
objNamesList.add(new ObjectName(1,1,1)); 
objNamesList.add(new ObjectName(2,2,2)); 
//intialize bundle instance
Bundle b = new Bundle();
//adding data into the bundle 
//key => objNames referece for the arrayList
//value => objNamesList , name of the arrayList 
//cast the arraylist into Serializable 
b.putSerializable("objNames", (Serializable) objNamesList);
//init the intent
Intent i = new Intent(CurrentActivity.this, NextActivity.class);
i.putExtras(b);
startActivity(i);

at next activity you will need to do as follows to get the arraylist

public class NextActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_next_activity);
        // get the bundle
        Bundle b = getIntent().getExtras();
        ArrayList<ObjectName> q = (ArrayList<ObjectName>) b.getSerializable("objNames");
    }
}