使用 notifyItemRemoved 或 notifyDataSetChanged 在 Android 中使用回收视图

我正在创建一个卡的列表，以显示使用回收视图，其中每卡有一个按钮，以删除该卡从名单。

当我使用 ()删除回收视图中的卡，它删除项目和动画罚款，但列表中的数据没有正确更新。

如果不是这样，我切换到 NotifyDataSetChanged ()，然后在清单中的项目被删除和更新正确，但是卡片不动画。

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

下面是我正在使用的一段代码:

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);
}
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最佳答案

As @pskink suggested it was supposed to be (index+1) in my case with notifyItemRemoved(index+1), probably because i am reserving the top index i.e. position=0 for a header.

小开

Use notifyItemRangeChanged(position, getItemCount()); after notifyItemRemoved(position);
You don't need to use index, just use position. See code below.

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();
}
小开

my mistake , notifyItemChanged(position) is helpless,the item of position can be removed ,and the item of position+1 is fine,but the items start from position+2,you will get an Exception, please use notifyItemRangeChanged(position,getItemCount()); after notifyItemRemoved(position);

like this:

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

Tried

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

and working like a charm.

小开

You can use getAdapterPosition() from the RecyclerView.ViewHolder

getLayoutPosition() provides the exact position of item in the layout and code is

holder.removeButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Position for remove
int modPosition= holder.getAdapterPosition();
//remove item from dataset
numbers.remove(modPosition);
//remove item from recycler view
if(numbers.isEmpty())
notifyDataSetChanged ()
else
notifyItemRemoved(modPosition);
                

}
});
小开 
**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;
}
小开

In my case I use Content Provider and a Custom RecyclerView Adapter with Cursor. This line of code is where you notify:

getContext().getContentResolver().notifyChange(uri, null);

Assuming In your recyclerView adapter (Delete Button):

Uri currentUri = ContentUris.withAppendedId(DatabaseContract.ToDoEntry.CONTENT_URI_TODO, id);
int rowsDeleted = mContext.getContentResolver().delete(currentUri, null, null);
if (rowsDeleted == 0) {
Log.d(TAG, "onClick: Delete failed");
} else {
Log.d(TAG, "onClick: Delete Successful");
}

And in your Database Provider:

case TODO_ID:
selection = DatabaseContract.ToDoEntry._ID + "=?";
selectionArgs = new String[] {String.valueOf(ContentUris.parseId(uri))};
rowsDeleted = database.delete(DatabaseContract.ToDoEntry.TODO_TABLE_NAME, selection, selectionArgs);
if (rowsDeleted != 0){
getContext().getContentResolver().notifyChange(uri, null);
}
return rowsDeleted;
小开

Use this it is working perfectly.

        issues.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, issues.size());

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