java - Android:存储用户点击的CardView

Question

我想创建一个用户点击过的 CardView 的列表。然后我想存储这些 CardView，然后通过电子邮件发送结果。下面是我的代码列表，如果您需要更多部分或有任何疑问，请在下面发布。谢谢。

回收 View 适配器:

    import android.content.Context;
    import android.support.v7.widget.RecyclerView;
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;


    import java.util.List;

    public class RecyclerViewAdapter extends 
    RecyclerView.Adapter<RecyclerViewHolders> {

private List<ItemObject> itemList;
private Context context;

public RecyclerViewAdapter(Context context, List<ItemObject> itemList) {
    this.itemList = itemList;
    this.context = context;
}

@Override
public RecyclerViewHolders onCreateViewHolder(ViewGroup parent, int viewType) {

    View layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_view_list, null);
    RecyclerViewHolders rcv = new RecyclerViewHolders(layoutView);
    return rcv;

}

@Override
public void onBindViewHolder(RecyclerViewHolders holder, int position) {
    //holder.countryName.setText(itemList.get(position).getName());
    holder.photo.setImageResource(itemList.get(position).getPhoto());
    holder.view = itemList.get(position).getView();


}

@Override
public int getItemCount() {

    Log.e("Test", "" + this.itemList.size());
    return this.itemList.size();

}


}

RecyclerViewHolder:

import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;


public class RecyclerViewHolders extends RecyclerView.ViewHolder implements View.OnTouchListener{

    //public TextView countryName;
    public ImageView photo;
    public ImageView fbumper;
    public View view;


    public RecyclerViewHolders(View itemView) {
        super(itemView);
        itemView.setOnTouchListener(this);
        photo = (ImageView)itemView.findViewById(R.id.cardview);
        //selected = false;
    }

    @Override
    public boolean onTouch(View view1, MotionEvent event) {
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                view.setVisibility(View.VISIBLE);

                break;

            case MotionEvent.ACTION_POINTER_UP:
                view.setVisibility(View.GONE);

                break;
        }

        return true;

    }
}

CarFrontFragment:(与 RecyclerView 结合使用的 fragment 示例)

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.text.Html;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageView;
import android.support.annotation.Nullable;
import java.util.List;
import java.util.ArrayList;

public class CarFrontFragment extends Fragment implements View.OnTouchListener {

    // Do not use static views.
    //Declaring variables/LayoutManager
    private LinearLayoutManager Layout;
    public ImageView bumper;
    public ImageView hood;

    @Nullable
    @Override
    //Making the fragment inflate (display) the view I need
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_car_front, container, false);
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        // Bind your views. (Setting my variables equal to what they need to be)
        RecyclerView list = (RecyclerView) view.findViewById(R.id.front_recyclerview);
        bumper = (ImageView) view.findViewById(R.id.fbumperselected);
        hood = (ImageView) view.findViewById(R.id.hoodselected);

        // Setting the onTouch to hide/show the bumper.
        view.setOnTouchListener(this);

        // Create your layout manager.
        Layout = new LinearLayoutManager(getContext());
        list.setLayoutManager(Layout);


        // Fetch your items.
        List<ItemObject> rowListItem = getAllItemList();


        // Set your adapter
        RecyclerViewAdapter adapter = new RecyclerViewAdapter(getContext(), rowListItem);
        list.setAdapter(adapter);

    }


    // Adding my items (CardViews) to the list to be displayed.
    private List<ItemObject> getAllItemList()
    {

        List<ItemObject> allItems = new ArrayList<ItemObject>();

        allItems.add(new ItemObject("Bumper", R.drawable.fbumper_card, bumper, false));

        allItems.add(new ItemObject("Hood", R.drawable.hood_card, hood, false));



        return allItems;
    }


    // Creating a new Fragment through newInstance.
    public static CarFrontFragment newInstance() {
        return new CarFrontFragment();
    }

    //Setting onTouch Events
    @Override
    public boolean onTouch(View view, MotionEvent event) {
        switch (event.getAction() & MotionEvent.ACTION_MASK)
        {
            case MotionEvent.ACTION_DOWN:
                break;

            case MotionEvent.ACTION_POINTER_UP:
                break;
        }

        return true;
    }

}

ItemObject:(对于 RecyclerView 中的每个项目)

import android.view.View;

public class ItemObject {

    private String name;
    private int photo;
    private View view;
    private Boolean selected;

    public ItemObject(String name, int photo, View view, boolean selected) {
        this.name = name;
        this.photo = photo;
        this.view = view;
        this.selected = selected;

    }

    public String getName() {
        return name;
    }

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

    public int getPhoto() {
        return photo;
    }

    public void setPhoto(int photo) {
        this.photo = photo;
    }

    public View getView() { return view; }

    public Boolean getSelected() {return selected;}


}

理想情况下，我希望列表只输出项目名称(如果为真)。希望我们能够让它发挥作用。再次感谢。

Answer 1

有几种不同的方法可以将该信息从 ViewHolder 传递到 Adapter。

查看this answer ，您可以看到一些选项，例如 EventBus 或使用 interface。

然而，为了让它更直接、更容易，我只是移动了一个类。如果您将 RecyclerViewHolders 移动到您的 RecyclerViewAdapter 类中，您将可以访问您的 itemList。

class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.RecyclerViewHolders> {

    private List<ItemObject> itemList;
    private Context context;

    public RecyclerViewAdapter(Context context, List<ItemObject> itemList) {
        this.itemList = itemList;
        this.context = context;
    }

    @Override
    public RecyclerViewHolders onCreateViewHolder(ViewGroup parent, int viewType) {
        View layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_view_list, null);
        RecyclerViewHolders rcv = new RecyclerViewHolders(layoutView);
        return rcv;

    }

    @Override
    public void onBindViewHolder(RecyclerViewHolders holder, int position) {
        holder.photo.setImageResource(itemList.get(position).getPhoto());
        holder.view = itemList.get(position).getView();
    }

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


    public class RecyclerViewHolders extends RecyclerView.ViewHolder implements View.OnTouchListener{

        ImageView photo;
        public View view;


        RecyclerViewHolders(View itemView) {
            super(itemView);
            itemView.setOnTouchListener(this);
            photo = itemView.findViewById(R.id.cardview);
        }

        @Override
        public boolean onTouch(View view1, MotionEvent event) {
            switch (event.getAction() & MotionEvent.ACTION_MASK) {
                case MotionEvent.ACTION_DOWN:
                    view.setVisibility(View.VISIBLE);
                    itemList.get(getAdapterPosition()).setSelected(true);
                    break;

                case MotionEvent.ACTION_POINTER_UP:
                    view.setVisibility(View.GONE);
                    itemList.get(getAdapterPosition()).setSelected(false);
                    break;
            }

            return true;
        }
    }
}

只要这些类不太复杂，这对您来说应该是一个非常简单的解决方案。如果这不起作用，我的下一个建议是使用 interface。