我正在探索RecyclerView,我很惊讶地看到,RecyclerView没有onItemClickListener()。

我有两个问题。

主要问题

我想知道为什么谷歌删除onItemClickListener()?

是否存在性能问题或其他问题?

次要的问题

我解决了我的问题写onClick在我的RecyclerView。适配器:

public static class ViewHolder extends RecyclerView.ViewHolder implements OnClickListener {

    public TextView txtViewTitle;
    public ImageView imgViewIcon;

    public ViewHolder(View itemLayoutView) {
        super(itemLayoutView);
        txtViewTitle = (TextView) itemLayoutView.findViewById(R.id.item_title);
        imgViewIcon = (ImageView) itemLayoutView.findViewById(R.id.item_icon);
    }

    @Override
    public void onClick(View v) {

    }
}

这样可以吗/有更好的办法吗?


当前回答

使用RxJava和PublishSubject为点击公开一个Observable。

public class ReactiveAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
    String[] mDataset = { "Data", "In", "Adapter" };

    private final PublishSubject<String> onClickSubject = PublishSubject.create();

    @Override 
    public void onBindViewHolder(final ViewHolder holder, int position) {
        final String element = mDataset[position];

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               onClickSubject.onNext(element);
            }
        });
    }

    public Observable<String> getPositionClicks(){
        return onClickSubject.asObservable();
    }
}

原来的帖子:

自从ListView的引入,onItemClickListener就一直存在问题。当你有一个内部元素的点击监听器时,回调不会被触发,但它没有被通知或良好的记录(如果有的话),所以有很多困惑和so问题。

考虑到RecyclerView更进一步,没有行/列的概念,而是任意布局的子节点数量,他们将onClick委托给每个子节点,或者委托给程序员实现。

不要认为Recyclerview是ListView的1:1替代品,而是一个更灵活的组件,用于复杂的用例。正如你所说,你的解决方案是谷歌对你的期望。现在您有了一个适配器,它可以将onClick委托给传递给构造函数的接口,这对于ListView和Recyclerview来说都是正确的模式。

public static class ViewHolder extends RecyclerView.ViewHolder implements OnClickListener {

    public TextView txtViewTitle;
    public ImageView imgViewIcon;
    public IMyViewHolderClicks mListener;

    public ViewHolder(View itemLayoutView, IMyViewHolderClicks listener) {
        super(itemLayoutView);
        mListener = listener;
        txtViewTitle = (TextView) itemLayoutView.findViewById(R.id.item_title);
        imgViewIcon = (ImageView) itemLayoutView.findViewById(R.id.item_icon);
        imgViewIcon.setOnClickListener(this);
        itemLayoutView.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (v instanceof ImageView){
           mListener.onTomato((ImageView)v);
        } else {
           mListener.onPotato(v);
        }
    }

    public static interface IMyViewHolderClicks {
        public void onPotato(View caller);
        public void onTomato(ImageView callerImage);
    }

}

然后在适配器上

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

   String[] mDataset = { "Data" };

   @Override
   public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
       View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.my_layout, parent, false);

       MyAdapter.ViewHolder vh = new ViewHolder(v, new MyAdapter.ViewHolder.IMyViewHolderClicks() { 
           public void onPotato(View caller) { Log.d("VEGETABLES", "Poh-tah-tos"); };
           public void onTomato(ImageView callerImage) { Log.d("VEGETABLES", "To-m8-tohs"); }
        });
        return vh;
    }

    // Replace the contents of a view (invoked by the layout manager) 
    @Override 
    public void onBindViewHolder(ViewHolder holder, int position) {
        // Get element from your dataset at this position 
        // Replace the contents of the view with that element 
        // Clear the ones that won't be used
        holder.txtViewTitle.setText(mDataset[position]);
    } 

    // Return the size of your dataset (invoked by the layout manager) 
    @Override 
    public int getItemCount() { 
        return mDataset.length;
    } 
  ...

Now look into that last piece of code: onCreateViewHolder(ViewGroup parent, int viewType) the signature already suggest different view types. For each one of them you'll require a different viewholder too, and subsequently each one of them can have a different set of clicks. Or you can just create a generic viewholder that takes any view and one onClickListener and applies accordingly. Or delegate up one level to the orchestrator so several fragments/activities have the same list with different click behaviour. Again, all flexibility is on your side.

它是一个非常需要的组件,非常接近我们的内部实现和到目前为止对ListView的改进。谷歌终于承认了这一点,这很好。

其他回答

看看我的方法:

首先像这样声明一个接口:

/**
 * Interface used for delegating item click events in a {@link android.support.v7.widget.RecyclerView}
 * Created by Alex on 11/28/2015.
 */
  public interface OnRecyclerItemClickListener<T> {

     /**
      * Called when a click occurred inside a recyclerView item view
      * @param view that was clicked
      * @param position of the clicked view
      * @param item the concrete data that is displayed through the clicked view
      */
      void onItemClick(View view, int position, T item);
   }

然后创建适配器:

public class CustomRecyclerAdapter extends RecyclerView.Adapter {      

    private class InternalClickListener implements View.OnClickListener{

      @Override
      public void onClick(View v) {
        if(mRecyclerView != null && mItemClickListener != null){
            // find the position of the item that was clicked
            int position = mRecyclerView.getChildAdapterPosition(v);
            Data data = getItem(position);
            // notify the main listener
            mItemClickListener.onItemClick(v, position, data);
        }
    }
}

private final OnRecyclerItemClickListener mItemClickListener;
private RecyclerView mRecyclerView;    
private InternalClickListener mInternalClickListener;


/**
 *
 * @param itemClickListener used to trigger an item click event
 */
public PlayerListRecyclerAdapter(OnRecyclerItemClickListener itemClickListener){        
    mItemClickListener = itemClickListener;
    mInternalClickListener = new InternalClickListener();
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
   View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item, parent, false);

    v.setOnClickListener(mInternalClickListener);

    ViewHolder viewHolder = new ViewHolder(v);
    return viewHolder;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    // do your binding here
}

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

@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    super.onAttachedToRecyclerView(recyclerView);

    mRecyclerView = recyclerView;
}

@Override
public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
    super.onDetachedFromRecyclerView(recyclerView);

    mRecyclerView = null;
}

public Data getItem(int position){
    return mDataset.get(position);
}
}

现在让我们看看如何从一个片段中整合这个:

public class TestFragment extends Fragment implements OnRecyclerItemClickListener<Data>{
   private RecyclerView mRecyclerView;

   @Override
   public void onItemClick(View view, int position, Data item) {
     // do something
   }

   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
      return inflater.inflate(R.layout.test_fragment, container, false);
   }

   @Override
   public void onViewCreated(View view, Bundle savedInstanceState) {
      mRecyclerView = view.findViewById(idOfTheRecycler);
      mRecyclerView .setAdapter(new CustomRecyclerAdapter(this));
   }

我用这个方法从RecyclerView开始一个Intent:

@Override
 public void onBindViewHolder(ViewHolder viewHolder, int i) {

    final MyClass myClass = mList.get(i);
    viewHolder.txtViewTitle.setText(myclass.name);
   ...
    viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
      @Override
       public void onClick(View v){
             Intent detailIntent = new Intent(mContext, type.class);                                                            
             detailIntent.putExtra("MyClass", myclass);
             mContext.startActivity(detailIntent);
       }
}
);

伙计们,在你们的主要活动中使用这个代码。非常有效的方法

RecyclerView recyclerView = (RecyclerView) findViewById(R.id.users_list);            
UsersAdapter adapter = new UsersAdapter(users, this);
recyclerView.setAdapter(adapter);
adapter.setOnCardClickListner(this);

下面是适配器类。

public class UsersAdapter extends RecyclerView.Adapter<UsersAdapter.UserViewHolder> {
        private ArrayList<User> mDataSet;
        OnCardClickListner onCardClickListner;


        public UsersAdapter(ArrayList<User> mDataSet) {
            this.mDataSet = mDataSet;
        }

        @Override
        public UserViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.user_row_layout, parent, false);
            UserViewHolder userViewHolder = new UserViewHolder(v);
            return userViewHolder;
        }

        @Override
        public void onBindViewHolder(UserViewHolder holder, final int position) {
            holder.name_entry.setText(mDataSet.get(position).getUser_name());
            holder.cardView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    onCardClickListner.OnCardClicked(v, position);
                }
            });
        }

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

        @Override
        public void onAttachedToRecyclerView(RecyclerView recyclerView) {
            super.onAttachedToRecyclerView(recyclerView);
        }


        public static class UserViewHolder extends RecyclerView.ViewHolder {
            CardView cardView;
            TextView name_entry;

            public UserViewHolder(View itemView) {
                super(itemView);
                cardView = (CardView) itemView.findViewById(R.id.user_layout);
                name_entry = (TextView) itemView.findViewById(R.id.name_entry);
             }
        }

        public interface OnCardClickListner {
            void OnCardClicked(View view, int position);
        }

        public void setOnCardClickListner(OnCardClickListner onCardClickListner) {
            this.onCardClickListner = onCardClickListner;
        }
    }

在此之后,您将在您的活动中获得这个覆盖方法。

@Override
    public void OnCardClicked(View view, int position) {
        Log.d("OnClick", "Card Position" + position);
    }

而不是实现接口视图。OnClickListener内部视图持有人或创建和接口和实现接口在您的活动.. 我使用这段代码简单的OnClickListener实现。

public static class SimpleStringRecyclerViewAdapter
            extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {

        // Your initializations goes here...
        private List<String> mValues;

        public static class ViewHolder extends RecyclerView.ViewHolder {

            //create a variable mView
            public final View mView;

            /*All your row widgets goes here
            public final ImageView mImageView;
            public final TextView mTextView;*/

            public ViewHolder(View view) {
                super(view);
                //Initialize it here
                mView = view;

                /* your row widgets initializations goes here
                mImageView = (ImageView) view.findViewById(R.id.avatar);
                mTextView = (TextView) view.findViewById(android.R.id.text1);*/
            }
        }

        public String getValueAt(int position) {
            return mValues.get(position);
        }

        public SimpleStringRecyclerViewAdapter(Context context, List<String> items) {

            mBackground = mTypedValue.resourceId;
            mValues = items;
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.list_item, parent, false);
            view.setBackgroundResource(mBackground);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(final ViewHolder holder, int position) {
            holder.mBoundString = mValues.get(position);
            holder.mTextView.setText(mValues.get(position));

            //Here it is simply write onItemClick listener here
            holder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Context context = v.getContext();
                    Intent intent = new Intent(context, ExampleActivity.class);

                    context.startActivity(intent);
                }
            });
        }

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

我喜欢这样,我正在用它

内部

public Adapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)

Put

View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_image_and_text, parent, false);
v.setOnClickListener(new MyOnClickListener());

在任何你想要的地方创建这个类

class MyOnClickListener implements View.OnClickListener {
    @Override
    public void onClick(View v) {
       int itemPosition = recyclerView.indexOfChild(v);
       Log.e("Clicked and Position is ",String.valueOf(itemPosition));
    }
}

我以前读过有一个更好的方法,但我喜欢这个方法,简单,不复杂。