Recyclerview适配器与kotlin

在适配器中可以通过两种方式实现项目点击监听器。

第一种方法是使用界面

在你的活动课上:

class YourActivity : AppCompatActivity(), TestAdapter.ClickListener {
...
override fun itemClicked() {

}
...
}

在适配器类中:

class MyAdapter : RecyclerView.Adapter<MyAdapter.MyViewHolder> {
...
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
     holder.textView1.setOnClickListener { 
        clickListener.itemClicked(position) 
     }
}
...
interface ClickListener {
     fun itemClicked(position : Int)
}
...
}

第二种方法是使用callBack调用

在适配器类中:

class MyAdapter(val callBack: (pos:Int) -> Unit) : RecyclerView.Adapter<MyAdapter.MyViewHolder> {
...
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
     holder.textView1.setOnClickListener { 
        callBack(position)
     }
}
}

在你的活动课上:

class YourActivity : AppCompatActivity() {
...
val testAdapter = TestAdapter(
            callBack = { index ->
               
            })
binding.recyclerView.layoutManager = LinearLayoutManager(this)
binding.recyclerView.adapter = testAdapter
...
}

这对我来说很难在活动中有一个项目点击监听器，也有一个项目的单一视图的点击监听器，不会触发项目点击监听器。在玩了Jacob Tabak的回答后，我尊重他的回答，如果项目内没有其他触摸操作，就点击项目。

我有一个自定义OnClickListener接口，有一个项目点击事件，它持有从适配器点击的项目的视图和项目的位置。我在构造函数(或者它可以是setter)中呈现它的一个实例，并将它附加到视图持有者容器click listener。

我也有其他的点击监听器在适配器(可以在视图持有人)，这将处理当前的视图点击从容器。

 public class MyRecyclerAdapter extends RecyclerView.Adapter<MyViewHolder> {

private ArrayList<String> mData;
private OnItemClickListener mOnItemClickListener;

public interface OnItemClickListener {
    public void onItemClick(View view, int position);
}

public MyRecyclerAdapter(ArrayList<String> itemsData,
        OnItemClickListener onItemClickListener) {
    mOnItemClickListener = onItemClickListener;
    this.mData = itemsData;
}

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

    View layoutView = LayoutInflater.from(mContext).inflate(
            R.layout.list_item, parent, false);

    final MyViewHolder viewHolder = new MyViewHolder(layoutView);

    viewHolder.container.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            mOnItemClickListener.onItemClick(v, viewHolder.getAdapterPosition());
        }
    });

    viewHоlder.button.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            //do button click work here with
            // mData.get( viewHolder.getAdapterPosition() );
        }
    });

    return viewHolder;
}

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

在活动中，您需要通过传递OnItemClickListener实例来初始化适配器

public class FeedActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    ...

    RecyclerView recyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);

    .....

    MyRecyclerAdapter adapter = new MyRecyclerAdapter(new ArrayList<String>(), new OnItemClickListener() {

        @Override
        public void onItemClick(View view, int position) {

            ///list item was clicked
        }
    });

    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    recyclerView.setAdapter(mFeedsAdapter);
}

还有我的ViewHolder

public class MyViewHolder extends RecyclerView.ViewHolder {

public Button button;
public View container;

public MyViewHolder(View itemLayoutView) {
    super(itemLayoutView);

    container = itemLayoutView;
    button = (Button) itemLayoutView.findViewById(R.id.button);
}}

RecyclerView没有OnClickListener，必须自己实现它。

我喜欢在适配器中添加OnItemClickListener接口，当您从ViewHolder中单击项目视图时调用onClick方法。因此，管理项目点击的职责不在ViewHolder和Adapter的范围内。将决定做什么的活动或片段

为监听器和监听器对象添加接口。

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

  ...

  private static OnItemClickListener onItemClickListener;

  ...

  public static interface OnItemClickListener {
      public void onItemClick(View view, int position);
  }

  ...
}

我们捕获项目根视图的单击，以及当回调触发时适配器上的onClick侦听器调用。

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

  ...

  private static OnItemClickListener onItemClickListener;

  ...

  public static interface OnItemClickListener {
      public void onItemClick(View view, int position);
  }

  ...

  public static class ViewHolder extends RecyclerView.ViewHolder {
      public ImageView imageView;

      public ViewHolder(View itemRootView) {
          super(itemRootView);
          imageView = (ImageView) itemRootView.findViewById(R.id.itemImage);

          itemRootView.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
                  int position  = ViewHolder.super.getAdapterPosition();
                  onItemClickListener.onItemClick(view,position);
              }
          });
      }
  }
}

由于活动或片段，片段在我们的情况下，我们分配一个监听器到适配器和onClick回调，我们将获得选定的项目的位置和打开一个详细的活动项目。

public class ItemsFragment extends Fragment {
    ...
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
       ...    
        ((ItemsAdapter) adapter).setOnItemClickListener(new ItemsAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                //Do something when an item has been clicked
            }
        });
        ...
    }
...
}

这里有一个更好的和不那么紧密耦合的方式来实现一个OnClickListener的RecyclerView。

用法片段:

RecyclerView recyclerView = findViewById(R.id.recycler);
recyclerView.addOnItemTouchListener(
    new RecyclerItemClickListener(context, recyclerView ,new RecyclerItemClickListener.OnItemClickListener() {
      @Override public void onItemClick(View view, int position) {
        // do whatever
      }

      @Override public void onLongItemClick(View view, int position) {
        // do whatever
      }
    })
);

RecyclerItemClickListener实现:

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;


public class RecyclerItemClickListener implements RecyclerView.OnItemTouchListener {
  private OnItemClickListener mListener;

  public interface OnItemClickListener {
    public void onItemClick(View view, int position);

    public void onLongItemClick(View view, int position);
  }

  GestureDetector mGestureDetector;

  public RecyclerItemClickListener(Context context, final RecyclerView recyclerView, OnItemClickListener listener) {
    mListener = listener;
    mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            return true;
        }

        @Override
        public void onLongPress(MotionEvent e) {
            View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
            if (child != null && mListener != null) {
                mListener.onLongItemClick(child, recyclerView.getChildAdapterPosition(child));
            }
        }
    });
}

  @Override public boolean onInterceptTouchEvent(RecyclerView view, MotionEvent e) {
    View childView = view.findChildViewUnder(e.getX(), e.getY());
    if (childView != null && mListener != null && mGestureDetector.onTouchEvent(e)) {
      mListener.onItemClick(childView, view.getChildAdapterPosition(childView));
      return true;
    }
    return false;
  }

  @Override public void onTouchEvent(RecyclerView view, MotionEvent motionEvent) { }

  @Override
  public void onRequestDisallowInterceptTouchEvent (boolean disallowIntercept){}
}

这是我所做的阅读更多和下载要点在这里

在这里添加相同的内容

CustomItemClickListener.java

public interface CustomItemClickListener {
 public void onItemClick(View v, int position);
}

ItemsListAdapter.java

public class ItemsListAdapter extends RecyclerView.Adapter<ItemsListAdapter.ViewHolder> {
ArrayList<ItemListSingleItem> data;

Context mContext;
CustomItemClickListener listener;

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View mView = LayoutInflater.from(parent.getContext()).inflate(R.layout.items_list_single_item, parent, false);
    final ViewHolder mViewHolder = new ViewHolder(mView);
    mView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            listener.onItemClick(v, mViewHolder.getAdapterPosition());
        }
    });
    return mViewHolder;
}

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    holder.itemTitle.setText(Html.fromHtml(data.get(position).getTitle()));
    if (!TextUtils.isEmpty(data.get(position).getThumbnailURL())) {
      // I Love picasso library :) http://square.github.io/picasso/
        Picasso.with(mContext).load(data.get(position).getThumbnailURL()).error(R.drawable.ic_no_image).
                placeholder(R.drawable.ic_no_image).
                transform(new RoundedCornersTransformation(5, 0)).
                into(holder.thumbnailImage);
    } else {
        holder.thumbnailImage.setImageResource(R.drawable.ic_no_image);
    }
}


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

public ItemsListAdapter(Context mContext, ArrayList<ItemsListSingleItem> data, CustomItemClickListener listener) {
    this.data = data;
    this.mContext = mContext;
    this.listener = listener;
}

public static class ViewHolder extends RecyclerView.ViewHolder {
    public TextView itemTitle;
    public ImageView thumbnailImage;

    ViewHolder(View v) {
        super(v);
        itemTitle = (TextView) v
                .findViewById(R.id.post_title);
        thumbnailImage = (ImageView) v.findViewById(R.id.post_thumb_image);
    }
 }
}

我是这样做的，没有不必要的类、检测器等。适配器中的简单代码。特别是针对longClick的更好解决方案。

public class PasswordAdapter extends RecyclerView.Adapter<PasswordAdapter.ViewHolder> {
    private final ClickListener clickListener;

    public PasswordAdapter(ClickListener clickListener) {
         this.clickListener = clickListener;
    }

    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
        TextView name;

        public ViewHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(this);
            itemView.setOnLongClickListener(this);
            name = (TextView) itemView.findViewById(R.id.card_name);
        }

        @Override
        public void onClick(View v) {
            int position = getBindingAdapterPosition();
            if (position >= 0) {
                clickListener.onItemClick(position, v);
            }
        }

        @Override
        public boolean onLongClick(View v) {
            int position = getBindingAdapterPosition();
            if (position >= 0) { 
                clickListener.onItemLongClick(position, v);
                return true;
            }
            return false;
        }
    }

    public interface ClickListener {
        void onItemClick(int position, View v);
        void onItemLongClick(int position, View v);
    }
}

然后在片段或活动中，点击:

PasswordAdapter mAdapter = new PasswordAdapter(
    new PasswordAdapter.ClickListener() {
        @Override
        public void onItemClick(int position, View v) {
            Log.d(TAG, "onItemClick position: " + position);
        }

        @Override
        public void onItemLongClick(int position, View v) {
            Log.d(TAG, "onItemLongClick pos = " + position);
        }
    }
);