在Android中使用notifyItemRemoved或notifyDataSetChanged与RecyclerView
我正在创build一个使用RecyclerView显示的卡片列表,其中每张卡片都有一个button来从列表中删除该卡片。
当我使用notifyItemRemoved()删除RecyclerView中的卡时,它删除项目和animation罚款,但列表中的数据不正确更新。
如果不是这样,我切换到notifyDataSetChanged()然后列表中的项目被删除并正确更新,但然后卡不animation。
有没有人有使用notifyItemRemoved()的经验,知道为什么它的行为不同于notifyDataSetChanged?
以下是我正在使用的一些代码:
private List<DetectedIssue> issues = new ArrayList<DetectedIssue>(); @Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { // - get element from your dataset at this position // - replace the contents of the view with that element if(position >0){ RiskViewHolder riskHolder = (RiskViewHolder)holder; final int index = position - 1; final DetectedIssue anIssue = issues.get(index); riskHolder.button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { try { int index = issues.indexOf(anIssue); issues.remove(anIssue); notifyItemRemoved(index); //notifyDataSetChanged(); } catch (SQLException e) { e.printStackTrace(); } } }); } } @Override public int getItemCount() { return (issues.size()+1); }
使用notifyItemRangeChanged(position,getItemCount()); notifyItemRemoved(position)之后;
你不需要使用索引,只是使用位置。 看下面的代码。
private List<DetectedIssue> issues = new ArrayList<DetectedIssue>(); @Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { // - get element from your dataset at this position // - replace the contents of the view with that element if(position >0){ RiskViewHolder riskHolder = (RiskViewHolder)holder; riskHolder.button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { try { issues.remove(position); notifyItemRemoved(position); //this line below gives you the animation and also updates the //list items after the deleted item notifyItemRangeChanged(position, getItemCount()); } catch (SQLException e) { e.printStackTrace(); } } }); } } @Override public int getItemCount() { return issues.size(); }
试着
public void removeItem(int position) { this.taskLists.remove(position); notifyItemRemoved(position); notifyItemRangeChanged(position, getItemCount() - position); }
并像魅力一样工作。
我的错误, notifyItemChanged(position)是无奈的,位置的项目可以被移除,位置+ 1的项目是罚款,但项目从位置+2开始,你会得到一个exception,请使用notifyItemRangeChanged(position,getItemCount ()); notifyItemRemoved(position)之后;
喜欢这个:
public void removeData(int position) { yourdatalist.remove(position); notifyItemRemoved(position); notifyItemRangeChanged(position,getItemCount()); }
作为@pskinkbuild议它应该是(index + 1)在我的情况下notifyItemRemoved(index+1)
,可能是因为我保留顶部索引,即position=0
的头。
您可以使用RecyclerView.ViewHolder
getLayoutPosition()
getLayoutPosition()
在布局和代码中提供项目的确切位置
holder.removeButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Position for remove int modPosition= holder.getLayoutPosition(); //remove item from dataset numbers.remove(modPosition); //remove item from recycler view notifyItemRemoved(modPosition); } });
**my solution looks like this** this way is unnecessary to use the heavy method: //notifyItemRangeChanged(xx,xx) /** * * recyclerView的item中的某一个view,获取其最外层的viewParent,也就是item对应的layout在adapter中的position * * @param recyclerView * @param view:can be the deep one inside the item,or the item itself . * @return */ public static int getParentAdapterPosition(RecyclerView recyclerView, View view, int parentId) { if (view.getId() == parentId) return recyclerView.getChildAdapterPosition(view); View viewGroup = (View) view.getParent(); if (viewGroup != null && viewGroup.getId() == parentId) { return recyclerView.getChildAdapterPosition(viewGroup); } //recursion return getParentAdapterPosition(recyclerView, viewGroup, parentId); } //wherever you set the clickListener . holder.setOnClickListener(R.id.rLayout_device_item, deviceItemClickListener); holder.setOnLongClickListener(R.id.rLayout_device_item, deviceItemLongClickListener); @Override public boolean onLongClick(View v) { final int position = ViewUtils.getParentAdapterPosition(rVDevicesList, v, R.id.rLayout_device_item); return true; }
您应该在ViewHolder类中添加删除侦听器
button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { onCancel(getAdapterPosition()); } }); private void onCancel(int position) { if (position >= issues.size()) return; issues.remove(position); notifyItemRemoved(position); }