RecyclerView实现Item点击事件处理

RecyclerView并没有像ListView那样提供了OnItemClick，OnItemLongClick等事件回调接口，所以，我们需要自己去实现。

为了后面的几种方式都可以用同一的回调接口来实现Click和LongClick事件，我们先定义一个回调事件接口。

public static interface OnItemClickListener {
        void onItemClick(View view);
        void onItemLongClick(View view);
    }

1 . 通过Adapter来处理

在Adapter的onCreateViewHolder和onBindViewHolder函数添加如下代码

    @Override
    public ListViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        ListViewHolder viewHolder = new ListViewHolder(
                mInflater.inflate(R.layout.list_item, parent, false));
        viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mItemClickListener.onItemClick(V);
            }
        });
        viewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                mItemClickListener.onItemLongClick(v);
                return true;
            }
        });

        return viewHolder;
    }
    
    @Override
    public void onBindViewHolder(ListViewHolder holder, final int position) {
        if (mData != null) {
            holder.mIndex.setText(Integer.toString(position));
            holder.mTitle.setText(mData.get(position).getTitle());
            holder.itemView.setTag(mData.get(position).getId());
        }
    }

其中，mItemClickListener为注册进来的Click回调监听，一般为对应的Activity或Fragment。在onBindViewHolder中，我们对ItemView设置了Tag属性，将数据的ID设置进去，在Activity或Fragment中可以通过获取view的Tag来获取当前点击item的Id值。另外，在中，可以直接通过RecyclerView.getChildAdapterPosition获取到当前点击的Item的列表索引。

    mListAdapter.setOnViewItemClickListener(new ListAdapter.OnItemClickListener()     {
        @Override
        public void onItemClick(View view) {
            int position = mRecyclerView.getChildAdapterPosition(view);
            Toast.makeText(this, "onItemClick : " + position, Toast.LENGTH_SHORT).show();
        }
        @Override
        public void onItemLongClick(View view) {
            int position = mRecyclerView.getChildAdapterPosition(view);
            Toast.makeText(this, "onItemLongClick : " + position, Toast.LENGTH_SHORT).show();
        }
    }

2 . 通过OnItemTouchListener来监听touch事件并转化为点击事件

创建类RecyclerViewItemTouchListener继承RecyclerView.SimpleOnItemTouchListener

public class RecyclerViewItemTouchListener extends RecyclerView.SimpleOnItemTouchListener {
    private OnItemClickListener mClickListener;
    private GestureDetectorCompat mGestureDetector;

    public RecyclerViewItemTouchListener(final RecyclerView recyclerView,
                                         OnItemClickListener listener) {
        this.mClickListener = listener;
        mGestureDetector = new GestureDetectorCompat(recyclerView.getContext(),
                new GestureDetector.SimpleOnGestureListener() {
                    @Override
                    public boolean onSingleTapUp(MotionEvent e) {
                        View childView = recyclerView.findChildViewUnder(e.getX(), e.getY());
                        if (childView != null && mClickListener != null) {
                            mClickListener.onItemClick(childView);
                        }
                        return true;
                    }

                    @Override
                    public void onLongPress(MotionEvent e) {
                        View childView = recyclerView.findChildViewUnder(e.getX(), e.getY());
                        if (childView != null && mClickListener != null) {
                            mClickListener.onItemLongClick(childView);
                        }
                    }
                });
    }

    @Override
    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
        mGestureDetector.onTouchEvent(e);
        return false;
    }
}

在Activity或Fragment中添加OnItemTouchListener。

    mRecyclerView.addOnItemTouchListener(new RecyclerViewItemTouchListener(mRecyclerView, new RecyclerViewItemTouchListener.OnItemClickListener() {

        @Override
        public void onItemClick(View view) {                
        }

        @Override
        public void onItemLongClick(View view, int position) {
        }
        });

3 . 通过OnChildAttachStateChangeListener在Item在Attach时添加点击事件
创建RecyclerViewClickSupport类，继承RecyclerView.OnChildAttachStateChangeListener

public class RecyclerViewClickSupport implements RecyclerView.OnChildAttachStateChangeListener {

    private View.OnClickListener mItemClickListener = null;
    private View.OnLongClickListener mItemLongClickListener = null;
    private RecyclerView mRecyclerView = null;

    public RecyclerViewClickSupport(RecyclerView view, View.OnClickListener listener,
                                    View.OnLongClickListener listener2){
        mRecyclerView = view;
        mItemClickListener = listener;
        mItemLongClickListener = listener2;
        view.addOnChildAttachStateChangeListener(this);
    }

    @Override
    public void onChildViewAttachedToWindow(View view) {
        if (mItemClickListener != null){
            view.setOnClickListener(mItemClickListener);
        }
        if (mItemLongClickListener != null){
            view.setOnLongClickListener(mItemLongClickListener);
        }
    }

    @Override
    public void onChildViewDetachedFromWindow(View view) {

    }

}

在Activity或Fragment中添加RecyclerViewClickSupport实现对RecyclerView的Item的点击事件的监听。

    mRCClickSupport = new RecyclerViewClickSupport(mRecyclerView, new View.OnClickListener() {
        @Override
        public void onClick(View v) {
        }
    }, new View.OnLongClickListener() {
        @Override
        public boolean onLongClick(View v) {
            return false;
        }
    });

以上的三种实现方式中，其中:

• 方式二没有办法对item的子view进行事件监听，而且因为没有为item真正的添加Click事件监听，所以Item的Click按下效果出不来。
• 方法一和方法三，更建议使用方法一，毕竟Adapter对Item的数据以及布局都有处理。
• 方法三可以封装为独立的类，但如果要处理子view，难免还要加入布局相关的代码，这样就进一个降低了代码的耦合。