How do I pass values from RecyclerView to AnotherA

问题:

I have a POJO class. It holds some Strings and I want to pass values from RecyclerView to an Activity. I tried something and failed. How do I do that?

Model

public class DetailModel {
    String title;

    public DetailModel() {
    }

    public DetailModel(String title) {
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

Adapter, onClick

holder.cardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                detailModel=new DetailModel();
                detailModels= new ArrayList<>();

                detailModel.setTitle(holder.headerText.getText().toString());

                Intent detailIntent = new Intent(context.getApplicationContext(), DetailActivity.class);

                context.startActivity(detailIntent);
            }
        });

Another Activity

DetailModel detailModel=new DetailModel();

        detailBody.setText(detailModel.getTitle());

回答1:

There is several ways to do that, but I will show you simplest one :

In your onBindViewHolder :

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder,final int position) {
    final MyView myHolder = (MyView) holder;
    myHolder.cardView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            detailModel.setTitle(holder.headerText.getText().toString());

            Intent detailIntent = new Intent(context, DetailActivity.class);
            //To pass your class:
            intent.putExtra("mypojo", details.get(position));
            context.startActivity(detailIntent);

        }
    });

}

In this way you must implement Serializable in your POJO class :

public class DetailModel implements Serializable{
String title;

public DetailModel() {
}

public DetailModel(String title) {
    this.title = title;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
    this.title = title;
}
}

And in second Activity use this code to get class :

getIntent().getExtras().getSerializable("mypojo");
//also you can cast extra 
DetailModel detailmodel=(Detailmodel) getIntent().getExtras().getSerializable("mypojo");
//if you implemented Parcelable
DetailModel detailmodel=(Detailmodel) getIntent().getExtras().getParcelable("mypojo");

This is the first way, in another and faster way is using Parcelable , checkout this answer but you must make some effort in Parcelable : how-to-send-an-object-from-one-android-activity-to-another-using-intent

I suggest you to use Parcelable maybe you need some time to learn it but you can feel speed difference in bigger classes.

Also if you have small amounts of Strings in your POJO, try to use intent extras instead of sending class like that :

intent.putExtra("model_name",pojo.getName());
//then get
getIntent().getExtras().getString("model_name");

回答2:

A recycler view by itself doesn't hold any data. That is the job of your adapter. The recyclerview' a job is to display that data and intercept touch events. So on your click listener get a hold of the data(POJO object) and pass that to your activity.