此篇博客代码引用开源项目BaseRecyclerViewAdapterHelper，GitHub地址：https://github.com/CymChad/BaseRecyclerViewAdapterHelper
最近还是在做小的项目demo，进度有点缓慢，刚刚缕清思路。recyclerview的整体是撸下来了，包括适配器，学会了一丢丢东西。写写笔记来巩固一下。
关于recyclerview的点击事件，网上有很多方法，我当时大概查了一下，有在适配器上添加的，有的改recyclerview的源码。我当时也是翻了很久，感觉还是那个开源项目写的比较好一点，毕竟在GitHub上面是star数目超过9k的。
先上代码吧：
public abstract class SimpleClickListener implements RecyclerView.OnItemTouchListener {
private GestureDetectorCompat mGestureDetector;
private RecyclerView recyclerView;
protected BaseQuickAdapter baseQuickAdapter;
public static String TAG = "SimpleClickListener";
private boolean mIsPrepressed = false;
private boolean mIsShowPress = false;
private View mPressedView = null;
@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
Log.i(TAG,">>>>onInterceptTouchEvent e"+e.getActionMasked());
if (recyclerView == null) {
this.recyclerView = rv;
this.baseQuickAdapter = (BaseQuickAdapter) recyclerView.getAdapter();
mGestureDetector = new GestureDetectorCompat(recyclerView.getContext(), new ItemTouchHelperGestureListener(recyclerView));
}else if (recyclerView!=rv){
this.recyclerView = rv;
this.baseQuickAdapter = (BaseQuickAdapter) recyclerView.getAdapter();
mGestureDetector = new GestureDetectorCompat(recyclerView.getContext(), new ItemTouchHelperGestureListener(recyclerView));
}
if (!mGestureDetector.onTouchEvent(e) && e.getActionMasked() == MotionEvent.ACTION_UP && mIsShowPress) {
if (mPressedView!=null){
BaseViewHolder vh = (BaseViewHolder) recyclerView.getChildViewHolder(mPressedView);
if (vh == null ||!isHeaderOrFooterView(vh.getItemViewType())) {
mPressedView.setPressed(false);
}
}
mIsShowPress = false;
mIsPrepressed = false;
}
return false;
}
@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
Log.i(TAG,">>>>onTouchEvent e"+e.getActionMasked());
mGestureDetector.onTouchEvent(e);
}
@Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
Log.i(TAG,">>>>onRequestDisallowInterceptTouchEvent disallowIntercept"+disallowIntercept);
}
private class ItemTouchHelperGestureListener extends GestureDetector.SimpleOnGestureListener {
private RecyclerView recyclerView;
ItemTouchHelperGestureListener(RecyclerView recyclerView) {
this.recyclerView = recyclerView;
}
@Override
public boolean onDown(MotionEvent e) {
mIsPrepressed = true;
mPressedView = recyclerView.findChildViewUnder(e.getX(), e.getY());
super.onDown(e);
return false;
}
@Override
public void onShowPress(MotionEvent e) {
Log.i(TAG,">>>>onShowPress e"+e);
if (mIsPrepressed && mPressedView != null) {
// mPressedView.setPressed(true);
mIsShowPress = true;
}
super.onShowPress(e);
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
Log.i(TAG,">>>>onSingleTapUp e"+e);
if (mIsPrepressed && mPressedView != null) {
if (recyclerView.getScrollState()!=RecyclerView.SCROLL_STATE_IDLE){
return false;
}
final View pressedView = mPressedView;
BaseViewHolder vh = (BaseViewHolder) recyclerView.getChildViewHolder(pressedView);
if (isHeaderOrFooterPosition(vh.getLayoutPosition())) {
return false;
}
Set<Integer> childClickViewIds = vh.getChildClickViewIds();
Set<Integer> nestViewIds = vh.getNestViews();
if (childClickViewIds != null && childClickViewIds.size() > 0) {
for (Integer childClickViewId : childClickViewIds) {
View childView = pressedView.findViewById(childClickViewId);
if (childView != null) {
if (inRangeOfView(childView, e) && childView.isEnabled()) {
if (nestViewIds!=null&&nestViewIds.contains(childClickViewId)){
return false;
}
setPressViewHotSpot(e, childView);
childView.setPressed(true);
onItemChildClick(baseQuickAdapter, childView, vh.getLayoutPosition() - baseQuickAdapter.getHeaderLayoutCount());
resetPressedView(childView);
return true;
} else {
childView.setPressed(false);
}
}
}
setPressViewHotSpot(e,pressedView);
mPressedView.setPressed(true);
for (Integer childClickViewId : childClickViewIds) {
View childView = pressedView.findViewById(childClickViewId);
if (childView!=null){
childView.setPressed(false);
}
}
onItemClick(baseQuickAdapter, pressedView, vh.getLayoutPosition() - baseQuickAdapter.getHeaderLayoutCount());
} else {
setPressViewHotSpot(e,pressedView);
mPressedView.setPressed(true);
if (childClickViewIds != null && childClickViewIds.size() > 0) {
for (Integer childClickViewId : childClickViewIds) {
View childView = pressedView.findViewById(childClickViewId);
if (childView!=null){
childView.setPressed(false);
}
}
}
onItemClick(baseQuickAdapter, pressedView, vh.getLayoutPosition() - baseQuickAdapter.getHeaderLayoutCount());
}
resetPressedView(pressedView);
}
return true;
}
private void resetPressedView(final View pressedView) {
if (pressedView!=null){
pressedView.postDelayed(new Runnable() {
@Override
public void run() {
if (pressedView!=null){
pressedView.setPressed(false);
}
}
}, 100);
}
mIsPrepressed = false;
mPressedView = null;
}
@Override
public void onLongPress(MotionEvent e) {
Log.i(TAG,">>>>onLongPress e"+e);
boolean isChildLongClick =false;
if (recyclerView.getScrollState()!=RecyclerView.SCROLL_STATE_IDLE){
return ;
}
if (mIsPrepressed && mPressedView != null) {
mPressedView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
BaseViewHolder vh = (BaseViewHolder) recyclerView.getChildViewHolder(mPressedView);
if (!isHeaderOrFooterPosition(vh.getLayoutPosition())) {
Set<Integer> longClickViewIds = vh.getItemChildLongClickViewIds();
Set<Integer> nestViewIds = vh.getNestViews();
if (longClickViewIds != null && longClickViewIds.size() > 0) {
for (Integer longClickViewId : longClickViewIds) {
View childView = mPressedView.findViewById(longClickViewId);
if (inRangeOfView(childView, e) && childView.isEnabled()) {
if (nestViewIds!=null&&nestViewIds.contains(longClickViewId)){
isChildLongClick=true;
break;
}
setPressViewHotSpot(e, childView);
onItemChildLongClick(baseQuickAdapter, childView, vh.getLayoutPosition() - baseQuickAdapter.getHeaderLayoutCount());
childView.setPressed(true);
mIsShowPress = true;
isChildLongClick = true;
break;
}
}
}
if (!isChildLongClick){
onItemLongClick(baseQuickAdapter, mPressedView, vh.getLayoutPosition() - baseQuickAdapter.getHeaderLayoutCount());
setPressViewHotSpot(e,mPressedView);
mPressedView.setPressed(true);
if (longClickViewIds != null) {
for (Integer longClickViewId : longClickViewIds) {
View childView = mPressedView.findViewById(longClickViewId);
childView.setPressed(false);
}
}
mIsShowPress = true;
}
}
}
}
}
private void setPressViewHotSpot(final MotionEvent e,final View mPressedView) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
/**
* when click Outside the region ,mPressedView is null
*/
if (mPressedView !=null && mPressedView.getBackground() != null) {
mPressedView.getBackground().setHotspot(e.getRawX(), e.getY()-mPressedView.getY());
}
}
}
/**
* Callback method to be invoked when an item in this AdapterView has
* been clicked.
*
* @param view The view within the AdapterView that was clicked (this
* will be a view provided by the adapter)
* @param position The position of the view in the adapter.
*/
public abstract void onItemClick(BaseQuickAdapter adapter, View view, int position);
/**
* callback method to be invoked when an item in this view has been
* click and held
*
* @param view The view whihin the AbsListView that was clicked
* @param position The position of the view int the adapter
* @return true if the callback consumed the long click ,false otherwise
*/
public abstract void onItemLongClick(BaseQuickAdapter adapter, View view, int position);
public abstract void onItemChildClick(BaseQuickAdapter adapter, View view, int position);
public abstract void onItemChildLongClick(BaseQuickAdapter adapter, View view, int position);
public boolean inRangeOfView(View view, MotionEvent ev) {
int[] location = new int[2];
if (view==null||!view.isShown()){
return false;
}
view.getLocationOnScreen(location);
int x = location[0];
int y = location[1];
if (ev.getRawX() < x
|| ev.getRawX() > (x + view.getWidth())
|| ev.getRawY() < y
|| ev.getRawY() > (y + view.getHeight())) {
return false;
}
return true;
}
private boolean isHeaderOrFooterPosition(int position) {
/**
* have a headview and EMPTY_VIEW FOOTER_VIEW LOADING_VIEW
*/
if (baseQuickAdapter==null){
if (recyclerView!=null){
baseQuickAdapter= (BaseQuickAdapter) recyclerView.getAdapter();
}else {
return false;
}
}
int type = baseQuickAdapter.getItemViewType(position);
return (type == EMPTY_VIEW || type == HEADER_VIEW || type == FOOTER_VIEW || type == LOADING_VIEW);
}
private boolean isHeaderOrFooterView(int type) {
return (type == EMPTY_VIEW || type == HEADER_VIEW || type == FOOTER_VIEW || type == LOADING_VIEW);
}}
在这里我大概说一下具体思路啊，首先这个类实现了RecyclerView.OnItemTouchListener，里面最重要的是onInterceptTouchEvent方法，主要用于拦截点击事件，返回的是false，因为我们要把点击事件让onTouchEvent方法处理。同时要初始化recyclerView、baseQuickAdapter、mGestureDetector实例。
后边还复写了onTouchEvent方法，可以看出在这个方法里，我们返回的是GestureDetectorCompat的实体类的点击方法。整体上就是利用GestureDetectorCompat手势监听处理点击事件。
下面先说一下各个方法的作用
OnDown(MotionEvent e)：用户按下屏幕就会触发；
onShowPress(MotionEvent e)：如果是按下的时间超过瞬间，而且在按下的时候没有松开或者是拖动的，那么onShowPress就会执行，具体这个瞬间是多久，我也不清楚呃……
onLongPress(MotionEvent e)：长按触摸屏，超过一定时长，就会触发这个事件 触发顺序： onDown->onShowPress->onLongPress
onSingleTapUp(MotionEvent e)：从名子也可以看出,一次单独的轻击抬起操作,也就是轻击一下屏幕，立刻抬起来，才会有这个触发，
当然,如果除了Down以外还有其它操作,那就不再算是Single操作了,所以也就不会触发这个事件
触发顺序：
点击一下非常快的（不滑动）Touchup：
onDown->onSingleTapUp->onSingleTapConfirmed
点击一下稍微慢点的（不滑动）Touchup：
onDown->onShowPress->onSingleTapUp->onSingleTapConfirmed
onFling() ：滑屏，用户按下触摸屏、快速移动后松开，由1个MotionEvent ACTION_DOWN, 多个ACTION_MOVE, 1个ACTION_UP触发
明白了这些方法名就可以继续分析代码了。
1.首先来看OnDown方法，这个在用户刚刚按下的时候就会触发，这个方法里可以找到点击的view，另外将控件被按下的标识mIsPrepressed至为true。
2.onShowPress方法按下控件超过瞬间被触发，
3.接下来看最重要的方法onSingleTapUp这个是轻击事件。
先从大概分析，首先排除三种可能性：
①当前view是否被点击且点击的view是否为空
②点前的点击事件是否是由于recyclerview的滚动而造成的点击效果
③当前点击的是否是recyclerview的底部或顶部控件，这要解释一下头部和底部并不是根据position为0来划分的，而是由item的type来决定的，如果想要深入了解这个的话，可以查看这个框架的viewholder。
这里解释一下为什么要排除，举个栗子QQ空间，假如是由于recyclerview组成的。最上面的你的背景墙很有可能就是recyclerview的头部，这个点击和下面的item的点击效果是不一样的。
以上效果排除以后才能算是真正得用户点击事件。
这里面还要针对item的布局做出不一样的效果，
①item中有可以点击的子view而且用户点击的也是子view
②item当中有点击的子view，但是用户点击范围不在这个子view当中
③item当中不包含可以点击的子view，直接出发item的点击
来看代码
Set<Integer> childClickViewIds = vh.getClickableItemIds();//获取item中可以点击的id
Set<Integer> nestViewIds = vh.getNestIds();//item中嵌套recyclerview
关于viewholder的这两个方法大家可以查看一下源码，这里不在赘述。
当item当中有可以点击的的子view时
for (Integer childClickViewId : childClickViewIds) {
View childView = pressedView.findViewById(childClickViewId);
if (childView != null) {
if (inRangeOfView(childView, e) && childView.isEnabled()) {//判断是否在点击范围内，且是否可以点击
if (nestViewIds != null && nestViewIds.contains(childClickViewId)) {
return false;//如果子view是recyclerview的话，不消耗
}
setPressViewHotSpot(e, childView);//修改childview的状态
childView.setPressed(true);
onItemChildClick(WXAdapter, childView, vh.getLayoutPosition());//执行itemchild点击
// onItemChildClick(WXAdapter, childView, vh.getLayoutPosition() - WeiXinAdapter.getHeaderLayoutCount());//设置点击事件
resetPressedView(childView);//重置childview的状态
return true;
} else {
childView.setPressed(false);//若点击范围不在child范围之类
}
}
}
注释已经写好了，大体就是遍历childview，查看点击范围是否属于childview的范围内，另外假如nestViewIds包含childview的id,也就是说子view如果也是recyclerview的时候，对点击事件不予处理。接下来最重要的一步就是实现onItemChildClick方法，里面可以处理点击逻辑事件。我感觉假如要处理的话，应该在添加一个手势检测吧。
假如执行完上面的一系列操作以后，childview的pressed仍然为false的话，说明用户点击不针对childview，则完成itemonclcik方法
/*后续为item维度点击*/
setPressViewHotSpot(e, pressedView);
mPressedView.setPressed(true);
for (Integer childClickViewId : childClickViewIds) {
View childView = pressedView.findViewById(childClickViewId);
if (childView != null) {
childView.setPressed(false);//将子view全都取消点击
}
}
onItemClick(WXAdapter, pressedView, vh.getLayoutPosition());//执行item点击
后面的代码跟前面逻辑是一样，只不过处理的是没有点击view的item，综上看来，我总觉得代码还是有重复性的，不知道是后来维护没有维护好，还是怎么回事，
for (Integer childClickViewId : childClickViewIds) {`}
循环遍历view的这段代码在最后的逻辑判断当中是没有必要的，因为前面已经判断过了。也许纯粹个人想法，没有看到其深奥之处。
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