在Android中使用notifyItemRemoved或notifyDataSetChanged与RecyclerView

Question

我正在创建一个使用RecyclerView显示的卡片列表,其中每张卡片都有一个按钮,可以从列表中删除该卡片.

当我使用notifyItemRemoved()删除RecyclerView中的卡时,它会删除项目和动画,但列表中的数据未正确更新.

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,但然后卡片不动画.

有人有使用notifyItemRemoved()的经验,并知道为什么它的行为与notifyDataSetChanged不同？

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);
}

Answer 1

使用notifyItemRangeChanged(position,getItemCount()); 在notifyItemRemoved(position)之后;
您不需要使用索引,只需使用位置.见下面的代码.

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();
}

Answer 2

试着

public void removeItem(int position) {
    this.taskLists.remove(position);
    notifyItemRemoved(position);
    notifyItemRangeChanged(position, getItemCount() - position);
}

和魅力一样工作.

Answer 3

我的错误, notifyItemChanged(位置)很无奈,位置项可以删除,位置项+ 1很好,但是项目从位置+ 2开始,你会得到一个例外,请使用notifyItemRangeChanged(position,getItemCount) ()); 在notifyItemRemoved(position)之后;

像这样:

public void removeData(int position) {
    yourdatalist.remove(position);
    notifyItemRemoved(position);
    notifyItemRangeChanged(position,getItemCount());
}

Answer 4

正如 @pskink 所建议的，在我的情况下，它应该是 (index+1) ，可能是因为我为标头notifyItemRemoved(index+1)保留了顶部索引 ie 。position=0