Android RecyclerView的Item點擊事件實現(xiàn)整理

更新時間：2017年01月19日 08:44:10 投稿：lqh

這篇文章主要介紹了Android RecyclerView的Item點擊事件實現(xiàn)整理的相關資料,需要的朋友可以參考下

自從開始使用RecyclerView代替ListView，會發(fā)現(xiàn)有很多地方需要學習。前一段時間的學習記錄有：

RecyclerView的滾動事件研究 - DevWiki
RecyclerView的ViewHolder和Adapter的封裝優(yōu)化 - DevWiki
RecyclerView問題記錄 - DevWiki

實現(xiàn) RecyclerView的Item的點擊事件有三種方式：

在創(chuàng)建 ItemView時添加點擊監(jiān)聽
當 ItemView attach RecyclerView時實現(xiàn)
通過RecyclerView已有的方法addOnItemTouchListener()實現(xiàn)

1.在創(chuàng)建ItemView時添加點擊監(jiān)聽

思路是：因為ViewHolder我們可以拿到每個Item的根布局，所以如果我們?yōu)楦季衷O置單獨的OnClick監(jiān)聽并將其開放給Adapter，那不就可以在組裝RecyclerView時就能夠設置ItemClickListener，只不過這個Listener不是設置到RecyclerView上而是設置到Adapter。具體實現(xiàn)代碼如下：

public class SampleAdapter extends RecyclerView.Adapter<SampleAdapter.SampleViewHolder> { 
 
  private List<DataBean> mDatas; 
  private OnItemClickListener mListener; // Item點擊事件 
 
  public DataBean getItem(int position) { 
    return mDatas == null ? null : mDatas.get(position); 
  } 
 
  @Override 
  public SampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent,false); 
    return new SampleViewHolder(itemView); 
  } 
 
  @Override 
  public void onBindViewHolder(SampleViewHolder holder, int position) { 
 
  } 
 
  @Override 
  public int getItemCount() { 
    return mDatas == null ? 0 : mDatas.size(); 
  } 
 
  class SampleViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener { 
 
    public SampleViewHolder(View itemView) { 
      super(itemView); 
      // TODO:初始化View 
      ... 
 
      itemView.setOnClickListener(this); 
      itemView.setOnLongClickListener(this); 
    } 
 
    @Override 
    public void onClick(View v) { 
      if (mListener != null) { 
        mListener.onItemClick(SampleAdapter.this, v, getLayoutPosition()); 
      } 
    } 
 
    @Override 
    public boolean onLongClick(View v) { 
      if (mListener != null) { 
        mListener.onItemLongClick(SampleAdapter.this, v, getLayoutPosition()); 
        return true; 
      } 
      return false; 
    } 
  } 
}

2.當ItemView attach RecyclerView時實現(xiàn)

該實現(xiàn)方法是在閱讀國外的一篇博客時發(fā)現(xiàn)的,原文鏈接如下：Getting your clicks on RecyclerView
實現(xiàn)的代碼如下：

public class ItemClickSupport { 
 
  private static final int KEY = 0x99999999; 
  private final RecyclerView mRecyclerView; 
  private OnItemClickListener mOnItemClickListener; 
  private OnItemLongClickListener mOnItemLongClickListener; 
 
  private View.OnClickListener mOnClickListener = new View.OnClickListener() { 
    @Override 
    public void onClick(View v) { 
      if (mOnItemClickListener != null) { 
        RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v); 
        mOnItemClickListener.onItemClicked(mRecyclerView, v, holder.getAdapterPosition()); 
      } 
    } 
  }; 
 
  private View.OnLongClickListener mOnLongClickListener = new View.OnLongClickListener() { 
    @Override 
    public boolean onLongClick(View v) { 
      if (mOnItemLongClickListener != null) { 
        RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v); 
        return mOnItemLongClickListener.onItemLongClicked(mRecyclerView, v, holder.getAdapterPosition()); 
      } 
      return false; 
    } 
  }; 
 
  private RecyclerView.OnChildAttachStateChangeListener mAttachListener = new RecyclerView.OnChildAttachStateChangeListener() { 
 
    @Override 
    public void onChildViewAttachedToWindow(View view) { 
      if (mOnItemClickListener != null) { 
        view.setOnClickListener(mOnClickListener); 
      } 
      if (mOnItemLongClickListener != null) { 
        view.setOnLongClickListener(mOnLongClickListener); 
      } 
    } 
 
    @Override 
    public void onChildViewDetachedFromWindow(View view) { 
    } 
  }; 
 
  /** 
   * ItemClickSupport的私有構(gòu)造方法 
   */ 
  private ItemClickSupport(RecyclerView recyclerView) { 
    mRecyclerView = recyclerView; 
    mRecyclerView.setTag(KEY, this); 
    // 為RecyclerView設置OnChildAttachStateChangeListener事件監(jiān)聽 
    mRecyclerView.addOnChildAttachStateChangeListener(mAttachListener); 
  } 
 
  /** 
   * 為RecyclerView設置ItemClickSupport 
   */ 
  public static ItemClickSupport addTo(RecyclerView view) { 
    ItemClickSupport support = (ItemClickSupport) view.getTag(KEY); 
    if (support == null) { 
      support = new ItemClickSupport(view); 
    } 
    return support; 
  } 
 
  /** 
   * 為RecyclerView移除ItemClickSupport 
   */ 
  public static ItemClickSupport removeFrom(RecyclerView view) { 
    ItemClickSupport support = (ItemClickSupport) view.getTag(KEY); 
    if (support != null) { 
      support.detach(view); 
    } 
    return support; 
  } 
 
  /** 
   * 為RecyclerView設置點擊事件監(jiān)聽 
   */ 
  public ItemClickSupport setOnItemClickListener(OnItemClickListener listener) { 
    mOnItemClickListener = listener; 
    return this; 
  } 
 
  /** 
   * 為RecyclerView設置長按事件監(jiān)聽 
   */ 
  public ItemClickSupport setOnItemLongClickListener(OnItemLongClickListener listener) { 
    mOnItemLongClickListener = listener; 
    return this; 
  } 
 
  /** 
   * 為RecyclerView移除OnChildAttachStateChangeListener事件監(jiān)聽 
   */ 
  private void detach(RecyclerView view) { 
    view.removeOnChildAttachStateChangeListener(mAttachListener); 
    view.setTag(KEY, null); 
  } 
 
  /** 
   * RecyclerView的點擊事件監(jiān)聽接口 
   */ 
  public interface OnItemClickListener { 
    void onItemClicked(RecyclerView recyclerView, View itemView, int position); 
  } 
 
  /** 
   * RecyclerView的長按事件監(jiān)聽接口 
   */ 
  public interface OnItemLongClickListener { 
    boolean onItemLongClicked(RecyclerView recyclerView, View itemView, int position); 
  } 
}

上面的代碼中給RecyclerView設置了OnChildAttachStateChangeListener事件監(jiān)聽，當子View attach RecyclerView時設置事件監(jiān)聽。

private RecyclerView.OnChildAttachStateChangeListener mAttachListener = new RecyclerView.OnChildAttachStateChangeListener() { 
 
 @Override 
  public void onChildViewAttachedToWindow(View view) { 
    if (mOnItemClickListener != null) { 
      view.setOnClickListener(mOnClickListener); 
    } 
    if (mOnItemLongClickListener != null) { 
      view.setOnLongClickListener(mOnLongClickListener); 
    } 
  } 
  
  @Override 
  public void onChildViewDetachedFromWindow(View view) {} 
};

使用時只需要調(diào)用addTo(RecycleView view)方法得到ItemClickSupport對象，然后調(diào)用setOnItemClickListener()方法和setOnItemLongClickListener()方法設置ItemView的點擊事件和長按事件監(jiān)聽即可。

3.通過RecyclerView已有的方法addOnItemTouchListener()實現(xiàn)

3.1、查看源碼

查看RecyclerView源碼可以看到,RecyclerView預留了一個Item的觸摸事件方法：

/** 
 * Add an {@link OnItemTouchListener} to intercept touch events before they are dispatched 
 * to child views or this view's standard scrolling behavior. 
 * 
 * <p>Client code may use listeners to implement item manipulation behavior. Once a listener 
 * returns true from 
 * {@link OnItemTouchListener#onInterceptTouchEvent(RecyclerView, MotionEvent)} its 
 * {@link OnItemTouchListener#onTouchEvent(RecyclerView, MotionEvent)} method will be called 
 * for each incoming MotionEvent until the end of the gesture.</p> 
 * 
 * @param listener Listener to add 
 * @see SimpleOnItemTouchListener 
 */ 
public void addOnItemTouchListener(OnItemTouchListener listener) { 
  mOnItemTouchListeners.add(listener); 
}

通過注釋我們可知,此方法是在滾動事件之前調(diào)用，需要傳入一個OnItemTouchListener對象。OnItemTouchListener的代碼如下：

public static interface OnItemTouchListener {  
  
  public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e); 
  
  public void onTouchEvent(RecyclerView rv, MotionEvent e); 
  
  public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept); 
}

此接口還提供了一個實現(xiàn)類，且官方推薦使用該實現(xiàn)類SimpleOnItemTouchListener：

/** 
 * An implementation of {@link RecyclerView.OnItemTouchListener} that has empty method bodies and 
 * default return values. 
 * 
 * You may prefer to extend this class if you don't need to override all methods. Another 
 * benefit of using this class is future compatibility. As the interface may change, we'll 
 * always provide a default implementation on this class so that your code won't break when 
 * you update to a new version of the support library. 
 */ 
public static class SimpleOnItemTouchListener implements RecyclerView.OnItemTouchListener { 
  <span style="font-family:'Microsoft YaHei';">  
</span>  @Override 
  public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) { 
    return false; 
  } 
  
  @Override 
  public void onTouchEvent(RecyclerView rv, MotionEvent e) { 
  } 
  
  @Override 
  public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) { 
  } 
}

在觸摸接口中，當觸摸時會回調(diào)一個MotionEvent對象，通過使用GestureDetectorCompat來解析用戶的操作。

3.2、了解GestureDetector的工作原理

對于觸摸屏，其原生的消息無非按下、抬起、移動這幾種，我們只需要簡單重載onTouch或者設置觸摸偵聽器setOnTouchListener即可進行處理。不過，為了提高我們的APP的用戶體驗，有時候我們需要識別用戶的手勢，Android給我們提供的手勢識別工具GestureDetector就可以幫上大忙了。

GestureDetector的工作原理是，當我們接收到用戶觸摸消息時，將這個消息交給GestureDetector去加工，我們通過設置偵聽器獲得GestureDetector處理后的手勢。

GestureDetector提供了兩個偵聽器接口，OnGestureListener處理單擊類消息，OnDoubleTapListener處理雙擊類消息。
OnGestureListener的接口有這幾個：

// 單擊，觸摸屏按下時立刻觸發(fā)  
abstract boolean onDown(MotionEvent e);  
// 抬起，手指離開觸摸屏時觸發(fā)(長按、滾動、滑動時，不會觸發(fā)這個手勢)  
abstract boolean onSingleTapUp(MotionEvent e);  
// 短按，觸摸屏按下后片刻后抬起，會觸發(fā)這個手勢，如果迅速抬起則不會  
abstract void onShowPress(MotionEvent e);  
// 長按，觸摸屏按下后既不抬起也不移動，過一段時間后觸發(fā)  
abstract void onLongPress(MotionEvent e);  
// 滾動，觸摸屏按下后移動  
abstract boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY);  
// 滑動，觸摸屏按下后快速移動并抬起，會先觸發(fā)滾動手勢，跟著觸發(fā)一個滑動手勢  
abstract boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY);  
OnDoubleTapListener的接口有這幾個：

// 雙擊，手指在觸摸屏上迅速點擊第二下時觸發(fā)  
abstract boolean onDoubleTap(MotionEvent e);  
// 雙擊的按下跟抬起各觸發(fā)一次  
abstract boolean onDoubleTapEvent(MotionEvent e);  
// 單擊確認，即很快的按下并抬起，但并不連續(xù)點擊第二下  
abstract boolean onSingleTapConfirmed(MotionEvent e);

有時候我們并不需要處理上面所有手勢，方便起見，Android提供了另外一個類SimpleOnGestureListener實現(xiàn)了如上接口，我們只需要繼承SimpleOnGestureListener然后重載需要的手勢即可。

3.3、實現(xiàn)點擊事件監(jiān)聽

了解了GestureDetector的工作原理之后，便開始實現(xiàn)RecycleView的Item的點擊事件。首先寫一個SimpleRecycleViewItemClickListener類繼承SimpleOnItemTouchListener，構(gòu)造時傳入Item點擊回調(diào)OnItemClickListener，并覆寫父類的boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e)方法，具體代碼如下：

/** 
 * RecyclerView的Item點擊事件監(jiān)聽 
 * 
 * @author liyunlong 
 * @date 2016/11/21 9:42 
 */ 
public class SimpleRecycleViewItemClickListener extends RecyclerView.SimpleOnItemTouchListener { 
 
  private OnItemClickListener mListener; 
  private GestureDetectorCompat mGestureDetector; 
 
  public SimpleRecycleViewItemClickListener(OnItemClickListener listener) { 
    this.mListener = listener; 
  } 
 
  @Override 
  public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) { 
    if (mGestureDetector == null) { 
      initGestureDetector(rv); 
    } 
    if (mGestureDetector.onTouchEvent(e)) { // 把事件交給GestureDetector處理 
      return true; 
    } else { 
      return false; 
    } 
  } 
 
  /** 
   * 初始化GestureDetector 
   */ 
  private void initGestureDetector(final RecyclerView recyclerView) { 
    mGestureDetector = new GestureDetectorCompat(recyclerView.getContext(), new GestureDetector.SimpleOnGestureListener() { // 這里選擇SimpleOnGestureListener實現(xiàn)類，可以根據(jù)需要選擇重寫的方法 
 
      /** 
       * 單擊事件 
       */ 
      @Override 
      public boolean onSingleTapUp(MotionEvent e) { 
        View childView = recyclerView.findChildViewUnder(e.getX(), e.getY()); 
        if (childView != null && mListener != null) { 
          mListener.onItemClick(childView, recyclerView.getChildLayoutPosition(childView)); 
          return true; 
        } 
        return false; 
      } 
 
      /** 
       * 長按事件 
       */ 
      @Override 
      public void onLongPress(MotionEvent e) { 
        View childView = recyclerView.findChildViewUnder(e.getX(), e.getY()); 
        if (childView != null && mListener != null) { 
          mListener.onItemLongClick(childView, recyclerView.getChildLayoutPosition(childView)); 
        } 
      } 
 
      /** 
       * 雙擊事件 
       */ 
      @Override 
      public boolean onDoubleTapEvent(MotionEvent e) { 
        int action = e.getAction(); 
        if (action == MotionEvent.ACTION_UP) { 
          View childView = recyclerView.findChildViewUnder(e.getX(), e.getY()); 
          if (childView != null && mListener != null) { 
            mListener.onItemDoubleClick(childView, recyclerView.getChildLayoutPosition(childView)); 
            return true; 
          } 
        } 
        return false; 
      } 
 
    }); 
 
  } 
 
  /** 
   * RecyclerView的Item點擊事件監(jiān)聽接口 
   * 
   * @author liyunlong 
   * @date 2016/11/21 9:43 
   */ 
  public interface OnItemClickListener { 
 
    /** 
     * 當ItemView的單擊事件觸發(fā)時調(diào)用 
     */ 
    void onItemClick(View view, int position); 
 
    /** 
     * 當ItemView的長按事件觸發(fā)時調(diào)用 
     */ 
    void onItemLongClick(View view, int position); 
 
    /** 
     * 當ItemView的雙擊事件觸發(fā)時調(diào)用 
     */ 
    void onItemDoubleClick(View view, int position); 
  } 
 
 
  /** 
   * RecyclerView的Item點擊事件監(jiān)聽實現(xiàn) 
   * 
   * @author liyunlong 
   * @date 2016/11/21 10:05 
   */ 
  public class SimpleOnItemClickListener implements OnItemClickListener { 
 
    @Override 
    public void onItemClick(View view, int position) { 
 
    } 
 
    @Override 
    public void onItemLongClick(View view, int position) { 
 
    } 
 
    @Override 
    public void onItemDoubleClick(View view, int position) { 
 
    } 
  } 
}

在GestureDetectorCompat的手勢回調(diào)中我們覆寫：

boolean onSingleTapUp(MotionEvent e)：單擊事件回調(diào)
void onLongPress(MotionEvent e)：長按事件回調(diào)
boolean onDoubleTapEvent(MotionEvent e)：雙擊事件回調(diào)

如果我們只需要監(jiān)聽單擊事件，而不需要監(jiān)聽長按事件和雙擊事件，構(gòu)造SimpleRecycleViewItemClickListener時只需要傳入SimpleOnItemClickListener即可，如果需要處理其它的手勢監(jiān)聽，也可以覆寫對應的手勢回調(diào)方法。

4.三種方法對比

以上三種方式分別是：