Question

I have a Parcelable which contains another Parcelable, both have an id. For the contained Parcelable I write id 22 but it reads 20. Why?

I constructed a complete example

Parcelable1

public class Parcelable1 implements Parcelable {
public int id = 11;
public Parcelable2 parcelable2;

public Parcelable1() {
    parcelable2 = new Parcelable2(22);
}

@Override
public int describeContents() {
    return hashCode();
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeInt(id);
    dest.writeParcelable(parcelable2, flags);
}

public static final Creator<Parcelable1> CREATOR = new Parcelable.Creator<Parcelable1>() {
    public Parcelable1 createFromParcel(Parcel source) {
        return new Parcelable1(source);
    }
    public Parcelable1[] newArray(int size) {
        return new Parcelable1[size];
    }
};

public Parcelable1(Parcel source) {
    id = source.readInt();
    
    parcelable2 = Parcelable2.CREATOR.createFromParcel(source);
}
}

Parcelable2

public class Parcelable2 implements Parcelable {
public int id = 22;

public Parcelable2(int id) {
    this.id = id;
}

@Override
public int describeContents() {
    return hashCode();
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    Log.d("test", "WRITE Parcelable2 id:" + id);
    
    dest.writeInt(id);
}

public static final Creator<Parcelable2> CREATOR = new Parcelable.Creator<Parcelable2>() {
    public Parcelable2 createFromParcel(Parcel source) {
        return new Parcelable2(source);
    }
    public Parcelable2[] newArray(int size) {
        return new Parcelable2[size];
    }
};

public Parcelable2(Parcel source) {
    id = source.readInt();
    
    Log.d("test", "READ Parcelable2 id:" + id);
}
}

Activity which passes the Parselable:

public class ParcelableTestActivity1 extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    
    findViewById(R.id.btn).setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(ParcelableTestActivity1.this, ParcelableTestActivity2.class);
            i.putExtra("par", new Parcelable1());
            startActivity(i);
        }
    });
}
}

The receiving activity:

public class ParcelableTestActivity2 extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main2);

    Parcelable1 p = (Parcelable1)getIntent().getParcelableExtra("par");
    
    Log.d("test", "parcelable 1 is: " + p + "id: " + p.id + " p2: " + p.parcelable2 + " p2.id: "  + p.parcelable2.id);
    
    Toast.makeText(this, "parc1 id: " + p.id + " parc2 id: " + p.parcelable2.id, Toast.LENGTH_LONG).show();
}
}

The outputs:

06-25 17:45:29.440: D/test(4107): READ Parcelable2 id:0

06-25 17:45:29.440: D/test(4107): parcelable 1 is: com.test.Parcelable1@4052e430id: 11 p2: com.test.Parcelable2@4052e6e0 p2.id: 0

06-25 17:47:19.968: D/test(4247): WRITE Parcelable2 id:22

06-25 17:47:19.988: D/test(4247): READ Parcelable2 id:20

06-25 17:47:19.988: D/test(4247): parcelable 1 is: com.test.Parcelable1@4052e238id: 11 p2: com.test.Parcelable2@4052e250 p2.id: 20

Answer 1

parcelable2 = Parcelable2.CREATOR.createFromParcel(source);

That’s your problem.

source:

• 22
• Parcelable2

When you pass source into the constructor for Parcelable 2, 22 gets set as parcelable2’s id.

You need to do this:

id = source.readInt();
parcelable2 = source.readParcelable(Parcelable2.class.getClassLoader())