轉載請註明出處：http://write.blog.csdn.net/postedit/40423361

在上一篇部落格Android-RecylerView初識中提到，RecyclerView不再負責Item檢視的佈局及顯示，所以RecyclerView也沒有為Item開放OnItemClick等點選事件，這就需要開發者自己實現。部落格最下面有Demo程式執行動畫。

在調研過程中，發現有同學修改RecyclerView原始碼來實現Item的點選監聽，但認為這不是一個優雅的解決方案，最終決定在RecyclerView.ViewHolder上做文章。

思路是：因為ViewHolder我們可以拿到每個Item的根佈局，所以如果我們為根佈局設定單獨的OnClick監聽並將其開放給Adapter，那不就可以在組裝RecyclerView時就能夠設定ItemClickListener，只不過這個Listener不是設定到RecyclerView上而是設定到Adapter。

我們首先看ViewHolder的程式碼：

public class MyViewHolder extends ViewHolder implements OnClickListener,OnLongClickListener{

	public ImageView iv;
	public TextView tv;
	private MyItemClickListener mListener;
	private MyItemLongClickListener mLongClickListener;
	
	public MyViewHolder(View rootView,MyItemClickListener listener,MyItemLongClickListener longClickListener) {
		super(rootView);
		iv = (ImageView)rootView.findViewById(R.id.item_iv);
		tv = (TextView)rootView.findViewById(R.id.item_tv);
		this.mListener = listener;
		this.mLongClickListener = longClickListener;
		rootView.setOnClickListener(this);
		rootView.setOnLongClickListener(this);
	}

	/**
	 * 點選監聽
	 */
	@Override
	public void onClick(View v) {
		if(mListener != null){
			mListener.onItemClick(v,getPosition());
		}
	}

	/**
	 * 長按監聽
	 */
	@Override
	public boolean onLongClick(View arg0) {
		if(mLongClickListener != null){
			mLongClickListener.onItemLongClick(arg0, getPosition());
		}
		return true;
	}

}</span>
 

下面要考慮的就是怎樣把listener傳遞進來。Demo中設定了監聽點選事件的Interface：MyItemClickListener:

public interface MyItemClickListener {
	public void onItemClick(View view,int postion);
}

上面提到過，listener是設定到Adapter上的，所以Adapter就需要對外開放相關方法：

@Override
	public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
		View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent,false);
		MyViewHolder vh = new MyViewHolder(itemView,mItemClickListener,mItemLongClickListener);
		return vh;
	}

	/**
	 * 設定Item點選監聽
	 * @param listener
	 */
	public void setOnItemClickListener(MyItemClickListener listener){
		this.mItemClickListener = listener;
	}
	
	public void setOnItemLongClickListener(MyItemLongClickListener listener){
		this.mItemLongClickListener = listener;
	}

最後就是組裝RecyclerView時根據需求設定點選監聽了：

/**
	 * 初始化RecylerView
	 */
	private void initView(){
		mRecyclerView = (RecyclerView)findViewById(R.id.recyclerView);
		MyLayoutManager manager = new MyLayoutManager(this);
		manager.setOrientation(LinearLayout.HORIZONTAL);//預設是LinearLayout.VERTICAL
		mRecyclerView.setLayoutManager(manager);
		mRecyclerView.setItemAnimator(new DefaultItemAnimator());
	}
	
	private void initData(){
		this.mData = new ArrayList<MyItemBean>();
		for(int i=0;i<20;i++){
			MyItemBean bean = new MyItemBean();
			bean.tv = "Xmy"+i;
			mData.add(bean);
		}
		this.mAdapter = new MyAdapter(mData);
		this.mRecyclerView.setAdapter(mAdapter);
		RecyclerView.ItemDecoration decoration = new MyDecoration(this);
		this.mRecyclerView.addItemDecoration(decoration);
		this.mAdapter.setOnItemClickListener(this);
		this.mAdapter.setOnItemLongClickListener(this);
	}

@Override
	public void onItemClick(View view, int postion) {
		MyItemBean bean = mData.get(postion);
		if(bean != null){
			Toast.makeText(this, bean.tv, Toast.LENGTH_SHORT).show();
		}
	}

	@Override
	public void onItemLongClick(View view, int postion) {
		MyItemBean bean = mData.get(postion);
		if(bean != null){
			Toast.makeText(this, "LongClick "+bean.tv, Toast.LENGTH_SHORT).show();
		}
	}