Question

我正在制作一个Android应用，其中我使用MongoDB和NodeJs作为后端服务。我在MongoDb上保存了一些帖子，并在回收器视图中检索它们。单击回收器视图时我有一个按钮，我想要获取项目的对象ID。

我已成功在回收站视图中获取所有文档，但问题是当我单击特定项目的按钮时，它们显示的是最近插入的文档的对象ID，而没有显示正确的项目对象ID。

这是我到目前为止所做的：

MyPostBookAdapter.java

public class MyPostedBookAdapter extends RecyclerView.Adapter<MyPostedBookAdapter.ViewHolder> {

List<PostedModel> listItem;
Activity context;
String id;

public MyPostedBookAdapter(List<PostedModel> listItem, Activity context){

    this.listItem = listItem;
    this.context = context;
}

@NonNull
@Override
public MyPostedBookAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {

    View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.posted_book,viewGroup,false);


    return new ViewHolder(v);
}

@Override
public void onBindViewHolder(@NonNull final MyPostedBookAdapter.ViewHolder viewHolder, final int i) {

    final PostedModel model =  listItem.get(i);

    //Object Id of post
    id = model.getPostId();

    viewHolder.userBookName.setText(model.getPurchaseBookName());

    RequestOptions requestOptions = new RequestOptions();
    requestOptions.placeholder(R.drawable.openbook);

    Glide.with(context).load(model.getPurchaseImage()).apply(requestOptions).into(viewHolder.userPostBook);

    viewHolder.delete.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {

            Toast.makeText(context,id,Toast.LENGTH_SHORT).show();

          }
    });
}

@Override
public int getItemCount() {
    return listItem.size();
}

public class ViewHolder extends RecyclerView.ViewHolder {

    ImageView userPostBook;
    TextView userBookName;
    Button delete;

    public ViewHolder(@NonNull View itemView) {
        super(itemView);

        userPostBook = (itemView).findViewById(R.id.userPostBook);
        userBookName = (itemView).findViewById(R.id.userBookName);
        delete = (itemView).findViewById(R.id.delete);
    }
  }
 }

PostedModel.java

public class PostedModel {

String purchaseImage,purchaseBookName,postId;

public PostedModel(){

}

public PostedModel(String purchaseImage, String purchaseBookName,String postId){

    this.purchaseBookName = purchaseBookName;
    this.purchaseImage = purchaseImage;
    this.postId = postId;
}

public String getPurchaseImage() {
    return purchaseImage;
}

public void setPurchaseImage(String purchaseImage) {
    this.purchaseImage = purchaseImage;
}

public String getPurchaseBookName() {
    return purchaseBookName;
}

public void setPurchaseBookName(String purchaseBookName) {
    this.purchaseBookName = purchaseBookName;
}

public String getPostId() {
    return postId;
}

public void setPostId(String postId) {
    this.postId = postId;
 }
}

请让我知道如何获取对应于正确项目的ObjectId。任何帮助将不胜感激。

谢谢

Answer 1

问题是

Recycler视图加载每个给定对象的对象，因此变量id具有最后一个对象的值。因此，您需要从选定的视图中获取ID。

解决方法是

@Override
public void onBindViewHolder(@NonNull final MyPostedBookAdapter.ViewHolder viewHolder, final int i) {

final PostedModel model =  listItem.get(i);

//Object Id of post
id = model.getPostId();

// You need to set this id to viewHolder.
viewHolder.userBookName.setId(id);

viewHolder.userBookName.setText(model.getPurchaseBookName());

RequestOptions requestOptions = new RequestOptions();
requestOptions.placeholder(R.drawable.openbook);

Glide.with(context).load(model.getPurchaseImage()).apply(requestOptions).into(viewHolder.userPostBook);

viewHolder.delete.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {

        //Here you can extract the id which we set at binding
        int idOfView = v.userBookName.getId();

        Toast.makeText(context,idOfView,Toast.LENGTH_SHORT).show();

      }
});

}

希望这会对您有所帮助。

无法使用mongoDb NodeJs作为后端在android中获取发布的对象ID

1 个答案: