error: incompatible types: Object cannot be converted to MyClass

Question

I want to use @Parcel annotation instead of implementing Parcelable.
So my class is :

@Parcel
public class UserSkillSpec {
    private final String TAG = getClass().getSimpleName();

    private Skill skill;
    private int endorses = 0;
    private boolean endorsed = false;
    private List<User> endorsers = new LinkedList<>();
    private int proficiency = 0;
    private boolean verified = false;

    @ParcelConstructor
    public UserSkillSpec(Skill skill, int proficiency) {
        this.skill = skill;
        this.proficiency = proficiency;
    }

}

when I want to build project, this error will appears in MessageBox

Error:(62, 109) error: incompatible types: Object cannot be converted to User

and User source code is :

@Parcel
@RealmClass
public class User extends RealmObject {
    @PrimaryKey
    private String id;

    private String firstName;
    private String lastName;
    private String name;
   //and something else

    public User() {
    }
}

Apparently this issue related to List.
How can I fix my problem?
Thanks.

EDIT1: I changed User class as below code:

@Parcel(implementations = {UserRealmProxy.class},
        value = Parcel.Serialization.BEAN,
        analyze = {User.class})
@RealmClass
public class User implements RealmModel {
    @PrimaryKey
    private String id;

    private String firstName;
    private String lastName;
    private String name;
    //somethings else

    public User() {
    }
}

in automatically generated class UserSkillSpec$$Parcelable by Parceler library,the error happened in for section :

public static void write(UserSkillSpec userSkillSpec$$1, android.os.Parcel parcel$$1, int flags$$0, IdentityCollection identityMap$$0) {
        int identity$$0 = identityMap$$0 .getKey(userSkillSpec$$1);
        if (identity$$0 != -1) {
            parcel$$1 .writeInt(identity$$0);
        } else {
            parcel$$1 .writeInt(identityMap$$0 .put(userSkillSpec$$1));
            Skill$$Parcelable.write(InjectionUtil.getField(Skill.class, UserSkillSpec.class, userSkillSpec$$1, "skill"), parcel$$1, flags$$0, identityMap$$0);
            parcel$$1 .writeInt(InjectionUtil.getField(int.class, UserSkillSpec.class, userSkillSpec$$1, "proficiency"));
            if (InjectionUtil.getField(List.class, UserSkillSpec.class, userSkillSpec$$1, "endorsers") == null) {
                parcel$$1 .writeInt(-1);
            } else {
                parcel$$1 .writeInt(InjectionUtil.getField(List.class, UserSkillSpec.class, userSkillSpec$$1, "endorsers").size());
                for (User user$$0 : InjectionUtil.getField(List.class, UserSkillSpec.class, userSkillSpec$$1, "endorsers")) {
                    User$$Parcelable.write(user$$0, parcel$$1, flags$$0, identityMap$$0);
                }
            }
            parcel$$1 .writeInt((InjectionUtil.getField(boolean.class, UserSkillSpec.class, userSkillSpec$$1, "verified")? 1 : 0));
            parcel$$1 .writeInt(InjectionUtil.getField(int.class, UserSkillSpec.class, userSkillSpec$$1, "endorses"));
            parcel$$1 .writeString(InjectionUtil.getField(String.class, UserSkillSpec.class, userSkillSpec$$1, "TAG"));
            parcel$$1 .writeInt((InjectionUtil.getField(boolean.class, UserSkillSpec.class, userSkillSpec$$1, "endorsed")? 1 : 0));
        }
    }

`@Parcel()` - shouldn't it be a `@Parcel`? Also on which line does the error appear? — Vladyslav Matviienko, Jun 08 '17 at 07:31
RealmObject is parcelable ? And Why do you assume this issue is related to List do you have more information with this error ? — Timo, Jun 08 '17 at 07:34
@Timo ,I need to declare User as Parcelable. Because I pass it through intent.putExtra somewhere. — Mojtaba, Jun 08 '17 at 07:41
Yes but you can't if you extends or your parents class need to be parcelable too — Timo, Jun 08 '17 at 07:43
Which Line is located the error ? Could you paste more ot the stacktrace ? — Timo, Jun 08 '17 at 08:10

Timo · Answer 1 · 2017-06-08T08:15:23.137

0

You should probably use implements over extend for your user, because your parent class is not parcelable.

Tips

You should consider to implement your custom creator like this

edited Jun 08 '17 at 08:15

answered Jun 08 '17 at 07:38

Timo

497
10
21

I replaced extends by implementing, but I could not solve error. – Mojtaba Jun 08 '17 at 07:51
And the part where you parce your object and get it back – Timo Jun 08 '17 at 07:53

score 0 · Accepted Answer · answered Jun 08 '17 at 10:59

Finally I could solve my problem,and decide to share it.
Tips: 1. List must be as Generic.List<Item> not List
2. use @ParcelPropertyConverter(ItemListParcelConverter.class) in declaration of List<Item>

so my code is like below now:

@Parcel(implementations = {UserRealmProxy.class},
        value = Parcel.Serialization.BEAN,
        analyze = {User.class})
public class User extends RealmObject {
    @PrimaryKey
    private String id;

    private String firstName;
    private String lastName;
    private String name;}

and this one:

@Parcel
public class UserSkillSpec {
    private Skill skill;
    private int endorses = 0;
    private boolean endorsed = false;
    @ParcelPropertyConverter(ItemListParcelConverter.class)
    private List<User> endorsers = new LinkedList<>();
    private int proficiency = 0;
    private boolean verified = false;

    public UserSkillSpec() {
    }
}

and this is parcelConvertor class:

public class ItemListParcelConverter<T> extends ArrayListParcelConverter<T> {
    @Override
    public void itemToParcel(T item, Parcel parcel) {
        parcel.writeParcelable(Parcels.wrap(item), 0);
    }

    @Override
    public T itemFromParcel(Parcel parcel) {
        return Parcels.unwrap(parcel.readParcelable(getClass().getClassLoader()));
    }
}

score 0 · Answer 3 · answered Sep 02 '18 at 09:25

If you want to use RealmModel instead of RealmObject you can follow this to working with Parceler library.

Ex Class:

@Parcel(implementations = { CustomAreaRealmProxy.class },
        value = Parcel.Serialization.BEAN,
        analyze = { CustomArea.class })
@RealmClass
public class CustomArea implements RealmModel {
    ...
}

And for your proguard file;

# Parceler library
-keep interface org.parceler.Parcel
-keep @org.parceler.Parcel class * { *; }
-keep class **$$Parcelable { *; }
-keepnames public class * extends io.realm.RealmObject
-keepnames public class * implements io.realm.RealmModel  #<- This is the fix

error: incompatible types: Object cannot be converted to MyClass

3 Answers3