Passing enum or object through an intent (the best solution)

Question

I have an activity that when started needs access to two different ArrayLists. Both Lists are different Objects I have created myself.

Basically I need a way to pa

Answer 1

Most of the answers that are using Parcelable concept here are in Java code. It is easier to do it in Kotlin.

Just annotate your enum class with @Parcelize and implement Parcelable interface.

@Parcelize
enum class ViewTypes : Parcelable {
TITLE, PRICES, COLORS, SIZES
}

Answer 2

about Oderik's post:

You can make your enum implement Parcelable which is quite easy for enums:

public enum MyEnum implements Parcelable { ... } You can than use Intent.putExtra(String, Parcelable).

If you define a MyEnum variable myEnum, then do intent.putExtra("Parcelable1", myEnum), you will get a "The method putExtra(String, Parcelable) is ambiguous for the type Intent" error message. because there is also a Intent.putExtra(String, Parcelable) method, and original 'Enum' type itself implements the Serializable interface, so compiler does not know choose which method(intent.putExtra(String, Parcelable/or Serializable)).

Suggest that remove the Parcelable interface from MyEnum, and move the core code into wrap class' Parcelable implementation, like this(Father2 is a Parcelable and contain an enum field):

public class Father2 implements Parcelable {

AnotherEnum mAnotherEnum;
int mField;

public Father2(AnotherEnum myEnum, int field) {
    mAnotherEnum = myEnum;
    mField = field;
}

private Father2(Parcel in) {
    mField = in.readInt();
    mAnotherEnum = AnotherEnum.values()[in.readInt()];
}

public static final Parcelable.Creator<Father2> CREATOR = new Parcelable.Creator<Father2>() {

    public Father2 createFromParcel(Parcel in) {
        return new Father2(in);
    }

    @Override
    public Father2[] newArray(int size) {
        return new Father2[size];
    }

};

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeInt(mField);
    dest.writeInt(mAnotherEnum.ordinal());
}

}

then we can do:

AnotherEnum anotherEnum = AnotherEnum.Z;
intent.putExtra("Serializable2", AnotherEnum.X);   
intent.putExtra("Parcelable2", new Father2(AnotherEnum.X, 7));

Answer 3

I like simple.

• The Fred activity has two modes -- HAPPY and SAD.
• Create a static IntentFactory that creates your Intent for you. Pass it the Mode you want.
• The IntentFactory uses the name of the Mode class as the name of the extra.
• The IntentFactory converts the Mode to a String using name()
• Upon entry into onCreate use this info to convert back to a Mode.

• You could use ordinal() and Mode.values() as well. I like strings because I can see them in the debugger.

  public class Fred extends Activity {
  
      public static enum Mode {
          HAPPY,
          SAD,
          ;
      }
  
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.betting);
          Intent intent = getIntent();
          Mode mode = Mode.valueOf(getIntent().getStringExtra(Mode.class.getName()));
          Toast.makeText(this, "mode="+mode.toString(), Toast.LENGTH_LONG).show();
      }
  
      public static Intent IntentFactory(Context context, Mode mode){
          Intent intent = new Intent();
          intent.setClass(context,Fred.class);
          intent.putExtra(Mode.class.getName(),mode.name());
  
          return intent;
      }
  }