AndroidRecyclerView的Item点击事件实现整理

AndroidRecyclerView的Item点击事件实现整理,第1张

概述自从开始使用RecyclerView代替ListView,会发现有很多地方需要学习。前一段时间的学习记录有:

自从开始使用RecyclerVIEw代替ListVIEw,会发现有很多地方需要学习。前一段时间的学习记录有:

RecyclerVIEw的滚动事件研究 - DevWiki
RecyclerVIEw的VIEwHolder和Adapter的封装优化 - DevWiki
RecyclerVIEw问题记录 - DevWiki

实现 RecyclerVIEw的Item的点击事件有三种方式:

在创建 ItemVIEw时添加点击监听 当 ItemVIEw attach RecyclerVIEw时实现 通过RecyclerVIEw已有的方法addOnItemtouchListener()实现

1.在创建ItemVIEw时添加点击监听

      思路是:因为VIEwHolder我们可以拿到每个Item的根布局,所以如果我们为根布局设置单独的OnClick监听并将其开放给Adapter,那不就可以在组装RecyclerVIEw时就能够设置ItemClickListener,只不过这个Listener不是设置到RecyclerVIEw上而是设置到Adapter。具体实现代码如下:

public class SampleAdapter extends RecyclerVIEw.Adapter<SampleAdapter.SampleVIEwHolder> {    private List<DataBean> mDatas;   private OnItemClickListener mListener; // Item点击事件    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,getLayoutposition());         return true;       }       return false;     }   } } 

2.当ItemVIEw attach RecyclerVIEw时实现

      该实现方法是在阅读国外的一篇博客时发现的,原文链接如下:Getting your clicks on RecyclerVIEw
实现的代码如下:

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,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,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的私有构造方法    */   private ItemClickSupport(RecyclerVIEw recyclerVIEw) {     mRecyclerVIEw = recyclerVIEw;     mRecyclerVIEw.setTag(KEY,this);     // 为RecyclerVIEw设置OnChildAttachStatechangelistener事件监听     mRecyclerVIEw.addOnChildAttachStatechangelistener(mAttachListener);   }    /**    * 为RecyclerVIEw设置ItemClickSupport    */   public static ItemClickSupport addTo(RecyclerVIEw vIEw) {     ItemClickSupport support = (ItemClickSupport) vIEw.getTag(KEY);     if (support == null) {       support = new ItemClickSupport(vIEw);     }     return support;   }    /**    * 为RecyclerVIEw移除ItemClickSupport    */   public static ItemClickSupport removeFrom(RecyclerVIEw vIEw) {     ItemClickSupport support = (ItemClickSupport) vIEw.getTag(KEY);     if (support != null) {       support.detach(vIEw);     }     return support;   }    /**    * 为RecyclerVIEw设置点击事件监听    */   public ItemClickSupport setonItemClickListener(OnItemClickListener Listener) {     mOnItemClickListener = Listener;     return this;   }    /**    * 为RecyclerVIEw设置长按事件监听    */   public ItemClickSupport setonItemLongClickListener(OnItemLongClickListener Listener) {     mOnItemLongClickListener = Listener;     return this;   }    /**    * 为RecyclerVIEw移除OnChildAttachStatechangelistener事件监听    */   private voID detach(RecyclerVIEw vIEw) {     vIEw.removeOnChildAttachStatechangelistener(mAttachListener);     vIEw.setTag(KEY,null);   }    /**    * RecyclerVIEw的点击事件监听接口    */   public interface OnItemClickListener {     voID onItemClicked(RecyclerVIEw recyclerVIEw,VIEw itemVIEw,int position);   }    /**    * RecyclerVIEw的长按事件监听接口    */   public interface OnItemLongClickListener {     boolean onItemLongClicked(RecyclerVIEw recyclerVIEw,int position);   } } 

      上面的代码中给RecyclerVIEw设置了OnChildAttachStatechangelistener事件监听,当子VIEw attach RecyclerVIEw时设置事件监听。

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) {} }; 

      使用时只需要调用addTo(RecycleVIEw vIEw)方法得到ItemClickSupport对象,然后调用setonItemClickListener()方法和setonItemLongClickListener()方法设置ItemVIEw的点击事件和长按事件监听即可。

3.通过RecyclerVIEw已有的方法addOnItemtouchListener()实现

3.1、查看源码

查看RecyclerVIEw源码可以看到,RecyclerVIEw预留了一个Item的触摸事件方法:

/**  * 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); } 

      通过注释我们可知,此方法是在滚动事件之前调用,需要传入一个OnItemtouchListener对象。OnItemtouchListener的代码如下:

public static interface OnItemtouchListener {      public boolean onIntercepttouchEvent(RecyclerVIEw rv,MotionEvent e);     public voID ontouchEvent(RecyclerVIEw rv,MotionEvent e);     public voID onRequestdisallowIntercepttouchEvent(boolean disallowIntercept); } 

此接口还提供了一个实现类,且官方推荐使用该实现类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 >  </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) {   } } 

      在触摸接口中,当触摸时会回调一个MotionEvent对象,通过使用GestureDetectorCompat来解析用户的 *** 作。

3.2、了解GestureDetector的工作原理

      对于触摸屏,其原生的消息无非按下、抬起、移动这几种,我们只需要简单重载ontouch或者设置触摸侦听器setontouchListener即可进行处理。不过,为了提高我们的APP的用户体验,有时候我们需要识别用户的手势,AndroID给我们提供的手势识别工具GestureDetector就可以帮上大忙了。

       GestureDetector的工作原理是,当我们接收到用户触摸消息时,将这个消息交给GestureDetector去加工,我们通过设置侦听器获得GestureDetector处理后的手势。

      GestureDetector提供了两个侦听器接口,OnGestureListener处理单击类消息,OnDoubleTapListener处理双击类消息。
OnGestureListener的接口有这几个:

// 单击,触摸屏按下时立刻触发  abstract boolean onDown(MotionEvent e);  // 抬起,手指离开触摸屏时触发(长按、滚动、滑动时,不会触发这个手势)  abstract boolean onSingleTapUp(MotionEvent e);  // 短按,触摸屏按下后片刻后抬起,会触发这个手势,如果迅速抬起则不会  abstract voID onShowPress(MotionEvent e);  // 长按,触摸屏按下后既不抬起也不移动,过一段时间后触发  abstract voID onLongPress(MotionEvent e);  // 滚动,触摸屏按下后移动  abstract boolean onScroll(MotionEvent e1,MotionEvent e2,float distanceX,float distanceY);  // 滑动,触摸屏按下后快速移动并抬起,会先触发滚动手势,跟着触发一个滑动手势  abstract boolean onFling(MotionEvent e1,float veLocityX,float veLocityY);  OnDoubleTapListener的接口有这几个:
// 双击,手指在触摸屏上迅速点击第二下时触发  abstract boolean onDoubleTap(MotionEvent e);  // 双击的按下跟抬起各触发一次  abstract boolean onDoubleTapEvent(MotionEvent e);  // 单击确认,即很快的按下并抬起,但并不连续点击第二下  abstract boolean onSingleTapConfirmed(MotionEvent e);  

有时候我们并不需要处理上面所有手势,方便起见,AndroID提供了另外一个类SimpleOnGestureListener实现了如上接口,我们只需要继承SimpleOnGestureListener然后重载需要的手势即可。

3.3、实现点击事件监听

      了解了GestureDetector的工作原理之后,便开始实现RecycleVIEw的Item的点击事件。首先写一个SimpleRecycleVIEwItemClickListener类继承SimpleOnItemtouchListener,构造时传入Item点击回调OnItemClickListener,并覆写父类的boolean onIntercepttouchEvent(RecyclerVIEw rv,MotionEvent e)方法,具体代码如下:

/**  * RecyclerVIEw的Item点击事件监听  *  * @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)) { // 把事件交给GestureDetector处理       return true;     } else {       return false;     }   }    /**    * 初始化GestureDetector    */   private voID initGestureDetector(final RecyclerVIEw recyclerVIEw) {     mGestureDetector = new GestureDetectorCompat(recyclerVIEw.getContext(),new GestureDetector.SimpleOnGestureListener() { // 这里选择SimpleOnGestureListener实现类,可以根据需要选择重写的方法        /**        * 单击事件        */       @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;       }        /**        * 长按事件        */       @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));         }       }        /**        * 双击事件        */       @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点击事件监听接口    *    * @author liyunlong    * @date 2016/11/21 9:43    */   public interface OnItemClickListener {      /**      * 当ItemVIEw的单击事件触发时调用      */     voID onItemClick(VIEw vIEw,int position);      /**      * 当ItemVIEw的长按事件触发时调用      */     voID onItemLongClick(VIEw vIEw,int position);      /**      * 当ItemVIEw的双击事件触发时调用      */     voID onItemDoubleClick(VIEw vIEw,int position);   }     /**    * RecyclerVIEw的Item点击事件监听实现    *    * @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的手势回调中我们覆写:

boolean onSingleTapUp(MotionEvent e):单击事件回调 voID onLongPress(MotionEvent e):长按事件回调 boolean onDoubleTapEvent(MotionEvent e):双击事件回调

      如果我们只需要监听单击事件,而不需要监听长按事件和双击事件,构造SimpleRecycleVIEwItemClickListener时只需要传入SimpleOnItemClickListener即可,如果需要处理其它的手势监听,也可以覆写对应的手势回调方法。

4.三种方法对比

以上三种方式分别是:

在创建ItemVIEw时添加点击监听 当ItemVIEw attach RecyclerVIEw时实现 通过RecyclerVIEw已有的方法addOnItemtouchListener()实现

从以上三种方式的实现过程可知:

三种均可实现ItemVIEw的点击事件和长按事件的监听。

第一种和第二种方式可以很方便对ItemVIEw中的子VIEw进行监听。

第三种方式可以很方便获取用户点击的坐标。

第二种方式和第三种方式可以写在单独的类中,相对于第一种写在Adapter的方式可使代码更独立整洁。

综上所述:

      如果你只想监听ItemVIEw的点击事件或长按事件,三种方式均可。

      如果你想监听ItemVIEw中每个子VIEw的点击事件,采用第一种或者第二种比较方便。

感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!

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