Question

我有一个自定义适配器类，它扩展了ArrayAdapter。我在我的活动中将适配器设置为listview。在我的objects列表中，我有8个对象。在listview显示加载时的5个对象（当我滚动listview时，它还有3个数据要显示）。滚动listview后，最后3个对象显示为与前3个对象相同。这是我试过的代码。

适配器

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if (convertView == null) {
        final MenuItem listItem = objects.get(position);
        holder = new Holder();
        LayoutInflater inflater = (LayoutInflater) this.context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.menu_list_item, parent);

        holder.textViewItemName = (TextView) convertView.findViewById(R.id.textViewItemName);
        holder.textViewItemName.setText(listItem.getItemName());

        holder.textViewPrice = (TextView) convertView.findViewById(R.id.textViewPrice);
        holder.textViewPrice.setText("$ ".concat(String.valueOf(listItem.getItemPrice())));

        holder.imageView = (ImageView) convertView.findViewById(R.id.imageViewItem);


        holder.buttonPlus = (ButtonRectangle) convertView.findViewById(R.id.buttonPlus);
        holder.cartQtyTextView = (TextView) convertView.findViewById(R.id.textViewCartQty);

        // Check & Set
        if (holder.buttonPlus != null) {
            holder.buttonPlus.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int i = 0;
                    if (holder.cartQtyTextView != null) {
                        holder.cartQtyTextView.setText("" + ++i);
                    }
                }
            });
        }
        holder.buttonPlus.setBackgroundColor(Color.WHITE);
        holder.buttonPlus.setTextColor(Color.parseColor("#333333"));

        holder.buttonMinus = (ButtonRectangle) convertView.findViewById(R.id.buttonMinus);

        // Check & Set
        if (holder.buttonMinus != null) {
            holder.buttonMinus.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int i = 0;
                    if (holder.cartQtyTextView != null) {
                        holder.cartQtyTextView.setText("" + --i);
                    }
                }
            });
        }
        holder.buttonMinus.setBackgroundColor(Color.WHITE);
        holder.buttonMinus.setTextColor(Color.parseColor("#333333"));
        convertView.setTag(holder);
    } else {
        holder = (Holder) convertView.getTag();
    }

    return convertView;
}

活动

listViweMenu.destroyDrawingCache();
listViweMenu.setVisibility(ListView.INVISIBLE);
listViweMenu.setVisibility(ListView.VISIBLE);
menuListAdapter.notifyDataSetChanged();
List<uk.co.bapos.android.baposwaiter.data.models.menu.MenuItem> itemsList
            = MenuItemController.fetchAllCategoryItems(this, String.valueOf(new ArrayList<>(menuItemData.entrySet()).get(position).getValue()));
listDataMenu.clear();
listDataMenu.addAll(itemsList);

我该如何解决这个问题？

Answer 1

您正在调用getTag（），setTag（）并将数据设置在错误的位置。试试这个：

ArrayAdapter adapter = myAdapter();//pass arraylist or data to adapter here
listview.setAdapter(adapter);

获取所有id的视图后，使用setTag（），如果view不为null，请使用getTag（）返回所有id。只有在将数据设置到视图之后。

活动：

{{1}}

Answer 2

试试这个。

LayoutInflater inflater = (LayoutInflater) this.context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
convertView = inflater.inflate(R.layout.menu_list_item, parent);
//initializing your view elements
 convertView.setTag(holder);
}
else{
holder = (Holder) convertView.getTag();
}
// do other stuff after if-else, setting the values to view elements

Answer 3

@Override public View getView(int position, View convertView, ViewGroup parent) 
 { 
if (convertView == null) 
  { 
    final MenuItem listItem = objects.get(position); 
    holder = new Holder(); LayoutInflater inflater = (LayoutInflater) this.context .getSystemService(Context.LAYOUT_INFLATER_SERVICE); convertView = inflater.inflate(R.layout.menu_list_item, parent);
    holder.textViewItemName = (TextView)convertView.findViewById(R.id.textViewItemName);
    holder.textViewPrice = (TextView) convertView.findViewById(R.id.textViewPrice);
    holder.imageView = (ImageView) convertView.findViewById(R.id.imageViewItem); 
    holder.buttonPlus = (ButtonRectangle) convertView.findViewById(R.id.buttonPlus); 
    holder.cartQtyTextView = (TextView) convertView.findViewById(R.id.textViewCartQty);
    holder.buttonMinus = (ButtonRectangle) convertView.findViewById(R.id.buttonMinus);  

   convertView.setTag(holder); }
   else 
     { 
   holder = (Holder) convertView.getTag();
    }
   holder.textViewItemName.setText(listItem.getItemName()); 
   holder.textViewPrice.setText("$ ".concat(String.valueOf(listItem.getItemPrice()))); // Check & Set if (holder.buttonPlus != null) { 
   holder.buttonPlus.setOnClickListener(new View.OnClickListener() 
  {

     @Override public void onClick(View v)
 {
 int i = 0; if (holder.cartQtyTextView != null) 
{ 
 holder.cartQtyTextView.setText("" + ++i); 
 } 
} 
  });
 } 

 holder.buttonPlus.setBackgroundColor(Color.WHITE);   
 holder.buttonPlus.setTextColor(Color.parseColor("#333333"));

 // Check & Set if (holder.buttonMinus != null)
 { 
 holder.buttonMinus.setOnClickListener(new View.OnClickListener() 
 { 
 @Override public void onClick(View v)
 {
  int i = 0; if (holder.cartQtyTextView != null) 
 { 
  holder.cartQtyTextView.setText("" + --i); 
  } 
 } }); } 
  holder.buttonMinus.setBackgroundColor(Color.WHITE);    
  holder.buttonMinus.setTextColor(Color.parseColor("#333333")); 
  return convertView; 
}

在android listview中滚动时如何修复重复项？

3 个答案: