我有一个问题，我一直在努力。我正在使用带有ViewHolder的ExpandableListView。我知道ExpandableListView重用了Views，这就是我认为我遇到的问题。
我在列表中有3个视图，如果我选择1然后选择2然后选择3，那么一切都很好，它会显示正确的子视图。虽然当我首先选择3时，所有其他子视图对于相同的groupPosition是相同的。如果我先选择2，那么3是正确的，但是1显示第三个子视图。
我希望将它们全部修复为正确的groupPosition，以便它们不会发生变化。
这是我的ExpandableListView适配器：
public class MenuListAdapter extends BaseExpandableListAdapter
{
private Context context;
private ArrayList<ListData> listData = new ArrayList<ListData>();
/**
* Constructor for the class.
*
* @param refContext This is a reference to the context of the ExpandableListAdapter being used in.
* @param refListData This is a reference to the ArrayList of ListData that will display the item data of the menu in the list.
*/
public MenuListAdapter(Context refContext, ArrayList<ListData> refListData)
{
context = refContext;
listData = refListData;
}
private static class ViewHolder
{
TextView title;
TextView description;
ImageView image;
ImageButton addItem;
}
@Override
public int getGroupCount()
{
return listData.size();
}
@Override
public int getChildrenCount(int groupPosition)
{
return 1; // There will only ever be 1 child in the group.
}
@Override
public Object getGroup(int groupPosition)
{
return groupPosition;
}
@Override
public Object getChild(int groupPosition, int childPosition)
{
return null;
}
@Override
public long getGroupId(int groupPosition)
{
return groupPosition;
}
@Override
public long getChildId(int groupPosition, int childPosition)
{
return childPosition;
}
@Override
public boolean hasStableIds()
{
return true; // Stops child views from resetting
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent)
{
final ViewHolder holder;
if(convertView == null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.listview_item, parent, false);
holder = new ViewHolder();
holder.title = (TextView) convertView.findViewById(R.id.titleTextView);
holder.image = (ImageView) convertView.findViewById(R.id.imageImageView);
holder.addItem = (ImageButton) convertView.findViewById(R.id.addItemImageButton);
/* The contents of the item View is set for every View in the list. */
holder.title.setText(listData.get(groupPosition).getTitle());
holder.image.setImageBitmap(listData.get(groupPosition).getImageBitmap());
holder.image.setTag(listData.get(groupPosition).getImageRes()); // Sets tag for image resource.
holder.image.setFocusable(false);// Enables the group view to be in focus in order to still be able to select the image and group.
holder.image.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
Integer imageResource = (Integer) holder.image.getTag(); // Get image resource from tag.
int resource = imageResource.intValue(); // Creates primitive image resource from object Integer.
Intent imageIntent = new Intent(context, ImageActivity.class);
imageIntent.putExtra("image_resource", resource); // Adds image resource as Extra to Intent.
context.startActivity(imageIntent);
}
});
holder.addItem.setFocusable(false); // Enables the group view to be in focus in order to still be able to select the button and group.
holder.addItem.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
/* AlertDialog that allows the user to select how many items they want of the item they selected. */
AlertDialog.Builder alertBuilder = new AlertDialog.Builder(context);
AlertDialog alertDialog;
LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View customView = layoutInflater.inflate(R.layout.item_quantity, null);
final NumberPicker quantityPicker = (NumberPicker) customView.findViewById(R.id.quantityPicker);
quantityPicker.setMinValue(1);
quantityPicker.setMaxValue(10);
quantityPicker.setDescendantFocusability(NumberPicker.FOCUS_BLOCK_DESCENDANTS); // Stops keyboard from appearing.
alertBuilder.setTitle("Select quantity");
alertBuilder.setView(customView);
alertBuilder.setPositiveButton("Confirm", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
int quantityAmount = quantityPicker.getValue(); // Gets value from NumberPicker.
/* Update checkout data. */
MainActivity mainActivity = (MainActivity) context;
mainActivity.updateCheckout(holder.title.getText().toString(), quantityAmount); // Updates checkout with added order.
dialog.cancel(); // Cancels AlertDialog.
Toast.makeText(context, "Order added to checkout!", Toast.LENGTH_SHORT).show();
}
});
alertBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which)
{
dialog.cancel(); // Cancels AlertDialog.
}
});
alertDialog = alertBuilder.create(); // Creates the AlertDialog View.
alertDialog.show(); // Shows the AlertDialog View.
}
});
convertView.setTag(holder);
}
else
{
holder = (ViewHolder) convertView.getTag();
}
return convertView;
}
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent)
{
final ViewHolder holder;
if(convertView == null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.listview_desc_item, parent, false);
holder = new ViewHolder();
holder.description = (TextView) convertView.findViewById(R.id.descriptionTextView);
holder.description.setText(listData.get(groupPosition).getDescription()); // Sets description of item View.
System.out.println("Group position: " + groupPosition);
System.out.println("Child position: " + childPosition);
convertView.setTag(holder);
}
else
{
holder = (ViewHolder) convertView.getTag();
}
return convertView;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition)
{
return false;
}
}
有人可以帮我解决这个问题。
答案 0 :(得分：3)
问题是视图回收，您只是在第一次通知视图时更新视图试试这个
if(convertView == null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.listview_desc_item, parent, false);
holder = new ViewHolder();
convertView.setTag(holder);
}
holder = (ViewHolder) convertView.getTag();
holder.description = (TextView) convertView.findViewById(R.id.descriptionTextView);
holder.description.setText(listData.get(groupPosition).getDescription());
System.out.println("Group position: " + groupPosition);
System.out.println("Child position: " + childPosition);
答案 1 :(得分：0)
有几个问题：
您正在null返回getChild()。
您将返回群组位置，而不是支持该群组的Object。
getChildrenCount()返回1.这只会返回一个孩子的项目。您应该返回总孩子数。
如果你看getChild()给你父母和孩子的位置。您应该使用适应该模式的数据结构。
以下是ExpandableListView我前段时间Context的实施方式example。它可以更好。例如，不需要将{{1}}传递给构造函数。