建设网站答题赚钱,网页设计公司企业组织结构图,旅游网站建设设计公司,建设银行官方个人网站之前发过一个databinding版的通用adapter#xff0c;能实现一般需求#xff0c;不过功能比较简陋#xff0c;实际开发中大家更倾向于使用BRVAH等功能丰富的第三方框架。现在给出一个基于BRVAH的databinding版通用Adapter。BaseAdapterabstract class BaseAdapter(private va…之前发过一个databinding版的通用adapter能实现一般需求不过功能比较简陋实际开发中大家更倾向于使用BRVAH等功能丰富的第三方框架。现在给出一个基于BRVAH的databinding版通用Adapter。BaseAdapterabstract class BaseAdapter(private val brId: Int, layoutId: Int, dataList: MutableList?): BaseQuickAdapter(layoutId, dataList) {...}构造函数比较长两个泛型T代表item的model类型即dataList的bean类型TBinding代表itemLayout对应生成的XXXBinding类比如itemLayout是fruit_item.xml对应的就是FruitItemBinding。三个个参数dataList和layoutId应该不用解释brId则对应itemLayout里相应variable的变量名比如variable的name是fruitbrId就是BR.fruit。数据绑定override fun onItemViewHolderCreated(viewHolder: BaseViewHolder, viewType: Int) {DataBindingUtil.bind(viewHolder.itemView)}final override fun convert(helper: BaseViewHolder, item: T) convert(helper, item, helper.layoutPosition)//final override fun convert(helper: BaseViewHolder, item: T, payloads: List) convert(helper, item, helper.layoutPosition, payloads)protected open fun convert(holder: BaseViewHolder, item: T, position: Int) {holder.getBinding()?.apply {setVariable(brId, item)executePendingBindings()}}//protected open fun convert(holder: BaseViewHolder, item: T, position: Int, payloads: List) {}重写onItemViewHolderCreated方法传入泛型TBinding并在convert方法里执行绑定。这里暴露了一个重载方法convert(holder: BaseViewHolder, item: T, position: Int)。用过BRVAH的程序猿都知道默认的convert方法里并不提供当前item对应的position这点不方便导致该框架被问的最多的问题之一就是“如何在convert方法里获取position” -_-! 这里直接在原来的convert方法里调用新增的重载方法并传入当前的position这样在子类里我们重写convert方法时就可以直接获得当前的position了。同时原convert方法被设置为final类型以确保其在子类中不被重写。点击监听扩展BRVAH默认的setOnItemClickListener有一点不好就是不提供当前的item只能通过dataList[position]或adpter.getItem(position) as T来获取。前者可能需要我们将dataList设置为全局变量后者更是需要做强制类型转换都不是很方便。现在我们丢掉自带监听重新实现一个能提供当前item的点击监听方法。private var onItemClickListener: ((BaseAdapter, View, Int, T) - Unit)? nullprivate var onItemLongClickListener: ((BaseAdapter, View, Int, T) - Boolean)? nullprivate var onItemChildClickListener: ((BaseAdapter, View, Int, T) - Unit)? nullprivate var onItemChildLongClickListener: ((BaseAdapter, View, Int, T) - Boolean)? nullprotected open fun setOnItemClick(view: View, position: Int, item: T) {onItemClickListener?.invoke(this, view, position, item)}protected open fun setOnItemLongClick(view: View, position: Int, item: T): Boolean {return onItemLongClickListener?.invoke(this, view, position, item) ?: false}protected open fun setOnItemChildClick(view: View, position: Int, item: T) {onItemChildClickListener?.invoke(this, view, position, item)}protected open fun setOnItemChildLongClick(view: View, position: Int, item: T): Boolean {return onItemChildLongClickListener?.invoke(this, view, position, item) ?: false}fun setOnItemClickListener(listener: (BaseAdapter, View, Int, T) - Unit) {onItemClickListener listener}fun setOnItemLongClickListener(listener: (BaseAdapter, View, Int, T) - Boolean) {onItemLongClickListener listener}fun setOnItemChildClickListener(listener: (BaseAdapter, View, Int, T) - Unit) {onItemChildClickListener listener}fun setOnItemChildLongClickListener(listener: (BaseAdapter, View, Int, T) - Boolean) {onItemChildLongClickListener listener}override fun bindViewClickListener(viewHolder: BaseViewHolder, viewType: Int) {onItemClickListener?.let {viewHolder.itemView.setOnClickListener { v -var position viewHolder.adapterPositionif (position RecyclerView.NO_POSITION) {returnsetOnClickListener}position - headerLayoutCountsetOnItemClick(v, position, getItem(position))}}onItemLongClickListener?.let {viewHolder.itemView.setOnLongClickListener { v -var position viewHolder.adapterPositionif (position RecyclerView.NO_POSITION) {returnsetOnLongClickListener false}position - headerLayoutCountsetOnItemLongClick(v, position, getItem(position))}}onItemChildClickListener?.let {for (id in getChildClickViewIds()) {viewHolder.itemView.findViewById(id)?.let { childView -if (!childView.isClickable) {childView.isClickable true}childView.setOnClickListener { v -var position viewHolder.adapterPositionif (position RecyclerView.NO_POSITION) {returnsetOnClickListener}position - headerLayoutCountsetOnItemChildClick(v, position, getItem(position))}}}}onItemChildLongClickListener?.let {for (id in getChildLongClickViewIds()) {viewHolder.itemView.findViewById(id)?.let { childView -if (!childView.isLongClickable) {childView.isLongClickable true}childView.setOnLongClickListener { v -var position viewHolder.adapterPositionif (position RecyclerView.NO_POSITION) {returnsetOnLongClickListener false}position - headerLayoutCountsetOnItemChildLongClick(v, position, getItem(position))}}}}}因为一并重写了长按和子控件的监听所以代码略有点长其实只需要看onItemClickListenersetOnItemClicksetOnItemClickListener和bindViewClickListener这四个方法就行了。首先private var onItemClickListener: ((BaseAdapter, View, Int, T) - Unit)? null这里onItemClickListener是一个函数对象(在kotlin里万物皆可定义为对象)具体实现在setOnItemClickListener时指定。setOnItemClick相比框架的原版方法多了一个参数item: T,以便暴露当前的item。然后重写BRVAH的bindViewClickListener方法将原版的setOnItemLongClick方法换成我们修改版的并传入当前item。这里顺便提一下为什么不用接口来实现监听。在java里我们通常使用接口来实现监听回调但在kotlin里更推荐将监听接口直接定义为函数对象因为kotlin接口不支持转换为lambda表达式而函数对象可以(kotlin调用java接口也可以)。如果要通过接口实现同时又不舍得放弃lambda则只能将接口写在外面的java类中。(不想多此一举的话还是选择函数对象吧)实现类adapterclass FruitAdapter (layoutId: Int, brId: Int, itemList: MutableList) : BaseAdapter(layoutId, brId, itemList)一行代码就搞定了如果需要执行其他操作就跟用BRVAH一样重写convert方法override fun convert(holder: BaseViewHolder, item: Fruit, position: Int) {super.convert(holder, item, position) //别忘了调用父类方法否则不会执行绑定...}同时BaseQuickAdapter的其他功能都被保留扩展阅读
