使用安全参数在片段抛出错误之间传递 arraylist of object

Question

I am working on an application where I need to pass the ArrayList model object to the next fragment but it is throwing an error. i tried many documents but nothing works please guide me why this is happening.I am retrieving data through firebase and want to set this ArrayList on my recyclerview adapter. how can I do that?? please guide me

CODE FROM FRAGMENT A

   ArrayList<RecyclerviewModel> mydatalist = new ArrayList<>();
                HomeFragmentDirections.ActionHomeToSearchDataFragment dr = HomeFragmentDirections.actionHomeToSearchDataFragment(mydatalist);
                Navigation.findNavController(view).navigate(dr);

CODE FROM FRAGMENT B(RECEIVING FRAGMENT)

 ArrayList<RecyclerviewModel> mylist;
    if (getArguments()!=null)
    {

        SearchDataFragmentArgs args = SearchDataFragmentArgs.fromBundle(getArguments());
        mylist = args.getMylist();
        adapter = new SearchRecycleAdapter(mylist, getContext());
        binding.searchDataRecyclerview.setAdapter(adapter);
        
    }

MODEL CLASS

public class RecyclerviewModel implements Parcelable {

String name;
String email;
String desc;
String book;
List<String> images;
String uid;
String searching;


public RecyclerviewModel() {
}

public RecyclerviewModel(String name, String email, String desc, String book, List<String> images, String uid,String searching) {
    this.name = name;
    this.email = email;
    this.desc = desc;
    this.book = book;
    this.images= images;
    this.uid = uid;
    this.searching = searching;
}

protected RecyclerviewModel(Parcel in) {
    name = in.readString();
    email = in.readString();
    desc = in.readString();
    book = in.readString();
    images = in.createStringArrayList();
    uid = in.readString();
    searching = in.readString();
}

public static final Creator<RecyclerviewModel> CREATOR = new Creator<RecyclerviewModel>() {
    @Override
    public RecyclerviewModel createFromParcel(Parcel in) {
        return new RecyclerviewModel(in);
    }

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

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public String getDesc() {
    return desc;
}

public void setDesc(String desc) {
    this.desc = desc;
}

public String getBook() {
    return book;
}

public void setBook(String book) {
    this.book = book;
}

public List<String> getImages() {
    return images;
}

public void setImages(List<String> images) {
    this.images = images;
}


public String getUid() {
    return uid;
}

public void setUid(String uid) {
    this.uid = uid;
}


public String getSearching() {
    return searching;
}

public void setSearching(String searching) {
    this.searching = searching;
}

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

@Override
public void writeToParcel(Parcel parcel, int i) {
    parcel.writeString(name);
    parcel.writeString(email);
    parcel.writeString(desc);
    parcel.writeString(book);
    parcel.writeStringList(images);
    parcel.writeString(uid);
    parcel.writeString(searching);
}

}

Navgraph ERROR IT IS THROWING

error: incompatible types: ArrayList<RecyclerviewModel> cannot be converted to RecyclerviewModel

Answer 1

You should create another empty class which extends ArrayList like this:

@Parcelize
public class RecyclerModels extends ArrayList<RecyclerViewModels> implements Parcelable

Then set the type of the navigation argument to this class.

<argument
  android:name="mylist"
  app:argType="your.package.RecyclerModels"/>

Your RecyclerViewModel should also be Parcelable

Answer 2

if you dont know, you are trying to do something like this somewhere:

ArrayList<RecyclerviewModel> arr=...;
RecyclerviewModel rm=arr;

so, check your code again.≈≈

you can use a class and interface to pass the data (its not the best way, but i use that)

public class Helper{
public static Sender sender;
interface Sender {
public void Send(Object object);
}
}

in fragment 2 (reciever):

Helper.sender = new Helper.Sender(){
public void Send(Object ob){
//What it should do on recieve ?
//e.g : RecyclerviewModel r=(RecyclerviewModel)ob;
}
}

in fragment 1 (sender):

//example:
Helper.sender.Send(RecyclerviewModel);

I hope this will help you:)